Caffeine in Tea Samples

 

S.No. Contents II Page No.
I. Introduction 4
II. Theory 6
III. Experiment 8
IV. Observation 10
V. Result 11
VI. Bibliography 12

Introduction

Tea is the most commonly and widely used soft beverage in the household. It acts as a stimulant for central nervous system and skeletal muscles. That is why tea removes fatigue, tiredness and headache. It also increases the capacity of thinking. It is also used for lowering body temperature. The principal constituent of tea, which is responsible for all these properties, is the alkaloid-caffeine. The amount of caffeine in tea leavers varies from sample to sample.

Originally it was thought that caffeine is responsible for the taste and flavour of tea. But pure caffeine has been found to be a tasteless while substance. Therefore, the taste and flavour of tea is due to some other substance present in it. There is a little doubt that the popularity of the xanthenes beverages depends on their stimulant action, although most people are unaware of any stimulation. The degree to which an individual is stimulated by given amount of caffeine varies from individual to individual.

For example, some people boast their ability to drink several cups of coffee in evening and yet sleep like a long, on the other hand there are people who are so sensitive to caffeine that even a single cup of coffee will cause a response boarding on the toxic.

The xanthene beverages also create a medical problem. They are dietary of a stimulant of the CNS. Often the physicians face the question whether to deny caffeine-containing beverages to patients or not. In fact children are more susceptible than adults to excitation by xanthenes.

For this reason, tea and coffee should be excluded from their diet. Even cocoa is of doubtful value. It has a high tannin content may be as high as 50 mg per cup.

After all our main stress is on the presence of caffeine in xanthene beverages and so in this project we will study and observe the quantity of caffeine varying in different samples of tea leaves.

Theory

The most important methylated alkaloid that occurs naturally is caffeine. Its molecular formula is CsH10N4O2. Its IUPAC name is 1, 3, 7-trimethylxanthene and common name is 1-methylated thiobromine.

Purely it is white, crystalline solid in the form of needles. Its melting point is 1230c. It is the main active principle component of tea leaves. It is present in tea leaves up to 3% and can be extracted by first boiling the tea leaves with water which dissolves many glycoside compounds in addition to caffeine. The clear solution is then treated with lead acetate to precipitate the glycoside compounds in the form of lead complex. The clear filtrate is then extracted with extracts caffeine because it is more soluble in it then water.

Uses of Caffeine :

1. In medicine, it is used to stimulate, central nervous system and to increase flow of urine.

2.  Because of its stimulating effects, caffeine has been used to relieve fatigue. But it is dangerous and one may collapse if not consumes it under certain limit.

3.  Caffeine is also used in analgesic tablets, as it is believed to be a pain reliever. It is also beneficial in migraines.

Effects of Caffeine

1. It is psycho – stimulant.

2.  It improves physical and mental ability.

3.  Its effect in learning is doubtful but intellectual performance may improve where it has been used to reduce fatigue or boredom.

4.When administered internally, it stimulates heart and nervous system and also acts as diuretic. On the contrary their excessive use is harmful to digestion and their long use leads to mental retardation.

Procedure

  1. First of all, 50 grams of tea leaves were taken as sample and 150 ml of water was added to it in a beaker.
  2. Then the beaker was heated up to extreme boiling.
  3. The solution was filtered and lead acetate was added to the filtrate, leading to the formation of a curdy brown coloured precipitate.
  4. We kept on adding lead acetate till no more precipitate has been formed.
  5. Again solution was filtered.
  6. Now the filtrate so obtained was heated until it had become 50 ml.
  7. Then the solution left was allowed to cool.
  8. After that, 20 ml. of chloroform was added to it.
  9. Soon after, two layers appeared in the separating funnel.
  10. We separated the lower layer.
  11. The solution then exposed to atmosphere in order to allow chloroform to get evaporated.
  12. The residue left behind was caffeine.
  13. Then we weighed it and recorded the observations.
  14. Similar procedure was performed with different samples of tealeaves and quantity of caffeine was observed in them

OBSERVATION

I. Red Label Tea (Brooke Bond)

Weight of china dish 46.60gms
Weight of china dish with precipitate 47.20gms.
Amount of caffeine 0.60gms
2.Yellow Label Tea (Lipton)
Weight of china dish 46.60gms
Weight of china dish with precipitate 47.15gms.
Amount of caffeine 0.55gms

3.Green Label Tea (Lipton)

Weight of china dish 46.60gms.
Weight of china dish with precipitate 47.05gms.
Amount of caffeine 0.45gms.

1. Quantity of caffeine in Red label tea is 60mg. /sample of 50 gm.

2. Quantity of caffeine in yellow label tea  is  55mg./sample  of 50 gm.

3. Quantity of caffeine in green label tea is 45mg./sample of 50 gm.

Graphically plotting various tea samples in accordance with the amount of caffeine present in them we present a stunning find:

60 mg 55 mg 45 mg
RED LABEL YELLOW LABEL GREEN LABEL

RESULT

Order of quantities of caffeine in different samples of tealeaves

Heel Label > Yellow Label > ten Label

BIBLIOGRAPHY

  • NCERT CHEMISTRY XII
  • ENCARTA ENCYCLOPEDIA 2009

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Caesin Present In Different Samples Of Milk – Chemistry Project

 

S.No. Contents II Page No.
I. Introduction
II. Requirements
III. Theory
IV. Procedure
V. Observation
VI. Conclusion
VII. Bibliography

Introduction

Milk is a complete diet as it contains in its Minerals, Vitamins, Proteins, Carbohydrates, Fats And Water. Average composition of milk from different sources is given below:

Source Water Mineral Protein Fats Carbohydrate
of milk (%) s (%) ns(%) (%) (%)
Cow 87.1 0.7 3.4 3.9 4.9
Human 87.4 0.2 1.4 4.0 4.9
Goat 87.0 0.7 3.3 4.2 4.8
Sheep 82.6 0.9 5.5 6.5 4.5

Casein is a major protein constituent in milk & is a mixed phosphor-protein. Casein has isoelectric pH of about 4.7 and can be easily separated around this isoelectric pH. It readily dissolves in dilute acids and alkalis. Casein is present in milk as calcium caseinate in the form of micelles. These micelles have negative charge and on adding acid to milk the negative charges are neutralized.

Ca2+-Caseinate +2CH3COOH(aq)-Caesin+(CH3COO)2Ca

REQUIREMENTS

>                 Beakers (250 ml)

>                 Filter-paper

>                 Glass rod

>                 Weight box

>                 Filtration flask

>                 Buchner funnel

>                 Test tubes

>                 Porcelain dish

>                 Different samples of milk

>                 1 % acetic acid solution

>                 Ammonium sulphate solution

Theory

Natural milk is an opaque white fluid. Secreted by the mammary glands of female mammal . The main constituents of natural milk are Protein, Carbohydrate, Mineral, Vitamins, Fats and Water and is a complete balanced diet. Fresh milk is sweetish in taste. However, when it is kept for long time at a temperature of 5 degree it becomes sour because of bacteria present in air . These bacteria convert lactose of milk into lactic acid which is sour in taste.    In acidic condition casein of milk starts separating out as a precipitate. When the acidity in milk is sufficient and the temperature is around 36 degree, it forms a semi-solid mass, called curd.

PROCEDURE

1. A clean dry beaker has been taken, followed by putting 20 ml of cow’s milk into it and adding 20 ml of saturated ammonium sulphate solution slowly and with stirring. Fat along with Caesin was precipitate out.

2. The solution was filtered and transferred the precipitates in another beaker. Added about 30 ml of water to the precipitate. Only Caesin dissolves in water forming milky solution leaving fat undissolved.

3. The milky solution was heated to about 40oC and add 1% acetic acid solution drop-wise, when casein got precipitated.

4. Filtered the precipitate, washed with water and the precipitate was allowed to dry.

5. Weighed the dry solid mass in a previously weighed watch glass.

6. The experiment was repeated with other samples of milk.

OBSERVATIONS

CONCLUSION

Different samples of milk contain different percentage of Caesin.

BIBLIOGRAPHY

  • NCERT CHEMISTRY XII
  • ENCARTA ENCYCLOPEDIA 2009

You can find other Chemistry Projects here.

Making Biodiesel From French Fries Oil

 

BD21295_INTRODUCTION

BD21300_TODAY

BD21300_PROPERTIES

BD21300_USES

BD21300_SAFETY

BD21300_COMPARISON TO PETROL FUELS

BD21300_CAN BIODIESEL BE PRODUCED

BD21300_PROBLEMS FACED

BD21295_PROCEDURE

BD21295_OBSERVATIONS

BD21295_PRECAUTIONS

BD21295_RESULT AND DISCUSSION

BD21295_BIBLIOGRAPHY

INTRODUCTION

Need for biodiesel:

In this advancing age, the importance of fuels is tremendous. The world runs on fuels such as petroleum and diesel. Every year, billions of tones of coal and natural gas are extracted and used up. But these, being natural resources, are nearing depletion levels. The search is on for alternative sources of fuel. This is where Biodiesel comes into the picture. Biodiesel has been around for about 100 years or so. But it is not used widely like petrol and diesel.

However, the petroleum industries were able to make inroads in fuel markets because their fuel was much cheaper to produce than the biomass alternatives. The result, for many years, was a near elimination of the biomass fuel production infrastructure.

Only recently, have environmental impact concerns and a decreasing price differential made biomass fuels such as biodiesel a growing alternative.

What is biodiesel?

imag12

Biodiesel is a renewable fuel that can be manufactured from algae, vegetable oils, animal fats or recycled restaurant greases; it can be produced locally in most countries.

Biodiesel refers to a diesel-equivalent processed fuel derived from biological sources (such as vegetable oils) which can be used in unmodified diesel-engine vehicles.

Chemically, transesterified biodiesel comprises a mix of mono-alkyl esters of long chain fatty acids.

It is distinguished from the straight vegetable oils (SVO) or waste vegetable oils (WVO) used as fuels in some diesel vehicles.

It is safe, biodegradable, non-toxic and reduces air pollutants, such as particulates, carbon monoxide and hydrocarbons.

Properties:

image12

  1. Biodiesel is a liquid which varies in color — between golden and dark brown — depending on the production feedstock.
  2. Biodiesel uncontaminated with starting material can be regarded as non-toxic.
  3. It is practically immiscible with water, has a high boiling point and low vapor pressure. Typical methyl ester biodiesel has a flash point of ~ 150 °C (300 °F).
  4. Biodiesel has a density of ~ 0.88 g/cm³, less than that of water..
  5. Biodiesel has about 5–8% less energy density , but better lubricity and more complete combustion can make the energy output of a diesel engine only 2% less per volume when compared to petro-diesel — or about 35 MJ/L
  6. The flash point of biodiesel (>150 °C) is significantly higher than that of petroleum diesel (64 °C) or gasoline (−45 °C). The gel point of biodiesel varies depending on the proportion of different types of esters contained.
  7. However, most biodiesel, including that made from soybean oil, has a somewhat higher gel and cloud point than petroleum diesel. In practice this often requires the heating of storage tanks, especially in cooler climates.

Uses:

images[4]

  1. Biodiesel can be used in pure form (B100) or may be blended with petroleum diesel at any concentration in most modern diesel engines.
  2. Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines. Biodiesel can also be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems.
  3. Biodiesel can also be used as a heating fuel in domestic and commercial boilers.

Safety:

Existing oil boilers may contain rubber parts and may require conversion to run on biodiesel, but the conversion process is usually relatively simple– involving the exchanging of rubber parts for synthetic ones due to biodiesel being a strong solvent.

Biodiesel will degrade natural rubber gaskets and hoses in vehicles. They should be replaced with FKM, which is nonreactive to biodiesel. However, this is more likely to occur where methanol used to catalyse the transesterification process has not been properly removed afterwards.

One should not burn B100 (pure 100% biodiesel) in an existing home heater without breaking it in, as biodiesel will dissolve coagulated heating oil, which can break off in chunks and cause problems.

The presence of water is a problem because:

  • Water reduces the heat of combustion of the bulk fuel. This means more smoke, harder starting, less power.
  • Water causes corrosion of vital fuel system components: fuel pumps, injector pumps, fuel lines, etc.
  • Water & microbes cause the paper element filters in the system to fail ( rot), which in turn results in premature failure of the fuel pump due to ingestion of large particles.
  • Water freezes to form ice crystals near 0 °C (32 °F). These crystals provide sites for nucleation and accelerate the gelling of the residual fuel.
  • Water accelerates the growth of microbe colonies, which can plug up a fuel system. Biodiesel users who have heated fuel tanks, therefore, face a year-round microbe problem.

When compared to petroleum fuels:

imag6

Biodiesel typically produces about 60% less net-lifecycle carbon dioxide emissions, as it is itself produced from atmospheric carbon dioxide via photosynthesis in plants.

However, the smog forming hydrocarbon emissions are 35% greater, and the Nitrogen Oxide emissions are also greater than those from petroleum-based diesel.

Some vehicle manufacturers are positive about the use of biodiesel, citing lower engine wear as one of the fuel’s benefits.

Biodiesel’s higher lubricity index compared to petrodiesel is an advantage and can contribute to longer fuel injector life.

Biodiesel is a better solvent than standard diesel, as it ‘cleans’ the engine, removing deposits in the fuel lines. It has been known to break down deposits of residue in the fuel lines of vehicles that have previously been run on petrodiesel.

However, this may cause blockages in the fuel injectors if an engine has been previously run on petroleum diesel for years.

Conversion to Biodiesel:

images[5]

Some operational problems were reported due to the high viscosity of vegetable oils compared to petroleum diesel fuel, which result in poor atomization of the fuel in the fuel spray and often leads to deposits and coking of the injectors, combustion chamber and valves.

Attempts to overcome these problems included heating of the vegetable oil, blending it with petroleum-derived diesel fuel or ethanol, pyrolysis and cracking of the oils.

Some International standards were set in order to regulate the quality of Biodiesel produced around the world.The standards ensure that the following important factors in the fuel production process are satisfied:

  • Complete reaction.
  • Removal of glycerin.
  • Removal of catalyst.
  • Removal of alcohol.
  • Absence of free fatty acids.
  • Low sulfur content.

Basic industrial tests to determine whether the products conform to the standards typically include gas chromatography, a test that verifies only the more important of the variables above.

Tests that are more complete are more expensive. Fuel meeting the quality standards is very non-toxic, with a toxicity rating (LD50) of greater than 50 mL/kg.

Importance of Biodiesel today:

Biodiesel is used by millions of car owners in Europe (particularly Germany).

Research sponsored by petroleum producers has found petroleum diesel better for car engines than biodiesel. This has been disputed by independent bodies, including for example the Volkswagen environmental awareness division, who note that biodiesel reduces engine wear.

Pure biodiesel produced ‘at home’ is in use by thousands of drivers who have not experienced failure, however, the fact remains that biodiesel has been widely available at gas stations for less than a decade, and will hence carry more risk than older fuels.

Many municipalities have started using 5% biodiesel (B5) in snow-removal equipment and other systems.

Biodiesel sold publicly is held to high standards set by national standards bodies.

Global biodiesel production reached 3.8 million tons in 2005. Approximately 85% of biodiesel production came from the European Union.

In the United States, biodiesel is the only alternative fuel to have successfully completed the Health Effects Testing requirements (Tier I and Tier II) of the Clean Air Act (1990).

Biodiesel is considered readily biodegradable under ideal conditions and non-toxic.

A University of Idaho study compared biodegradation rates of biodiesel, neat vegetable oils, biodiesel and petroleum diesel blends, and neat 2-D diesel fuel.

Using low concentrations of the product to be degraded (10 ppm) in nutrient and sewage sludge amended solutions, they demonstrated

mphasentrenner

Separation of droplets and solids at phase separation profiles

that biodiesel degraded at the same rate as a dextrose control and 5 times as quickly as petroleum diesel over a period of 28 days, and that biodiesel blends doubled the rate of petroleum diesel degradation through co-metabolism.

The same study examined soil degradation using 10 000 ppm of biodiesel and petroleum diesel, and found biodiesel degraded at twice the rate of petroleum diesel in soil.

In all cases, it was determined biodiesel also degraded more completely than petroleum diesel, which produced poorly degradable undetermined intermediates.

Toxicity studies for the same project demonstrated no mortalities and few toxic effects on rats and rabbits with up to 5000 mg/kg of biodiesel.

Petroleum diesel showed no mortalities at the same concentration either, however toxic effects such as hair loss and urinary discolouring were noted with concentrations of >2000 mg/l in rabbits.

Since biodiesel is more often used in a blend with petroleum diesel, there are fewer formal studies about the effects on pure biodiesel in unmodified engines and vehicles in day-to-day use.

Can Biodiesel be produced?

image4

Chemically, transesterified biodiesel comprises a mix of mono-alkyl esters of long chain fatty acids.

The most common form uses methanol to produce methyl esters as it is the cheapest alcohol available, though ethanol can be used to produce an ethyl ester biodiesel and higher alcohols such as isopropanol and butanol have also been used. Using alcohols of higher molecular weights improves the cold flow properties of the resulting ester, at the cost of a less efficient transesterification reaction.

A lipid transesterification production process is used to convert the base oil to the desired esters. Any Free fatty acids (FFAs) in the base oil are either converted to soap and removed from the process, or they are esterified (yielding more biodiesel) using an acidic catalyst.

After this processing, unlike straight vegetable oil, biodiesel has combustion properties very similar to those of petroleum diesel, and can replace it in most current uses.

A byproduct of the transesterification process is the production of glycerol. For every 1 tonne of biodiesel that is manufactured, 100 kg of glycerol are produced. Originally, there was a valuable market for the glycerol, which assisted the economics of the process as a whole. However, with the increase in global biodiesel production, the market price for this crude glycerol (containing 20% water and catalyst residues) has crashed.

  • Raw material needed for production of Biodiesel:

imag2

A variety of oils can be used to produce biodiesel. These include:

  1. Virgin oil feedstock; rapeseed and soybean oils are most commonly used, soybean oil alone accounting for about ninety percent of all fuel stocks; It also can be obtained from field pennycress and Jatropha[22] other crops such as mustard, flax, sunflower, canola, palm oil, hemp, and even algae show promise.
  2. Waste vegetable oil (WVO);
  3. Animal fats including tallow, lard, yellow grease, chicken fat,[22] and the by-products of the production of Omega-3 fatty acids from fish oil.
  4. Sewage. A company in New Zealand has successfully developed a system for using sewage waste as a substrate for algae and then producing bio-diesel.

Problems faced:

bio4

Worldwide production of vegetable oil and animal fat is not yet sufficient to replace liquid fossil fuel use.

Furthermore, some environmental groups object to the vast amount of farming and the resulting over-fertilization, pesticide use, and land use conversion that they say would be needed to produce the additional vegetable oil.

  • Many advocates suggest that waste vegetable oil is the best source of oil to produce biodiesel. However, the available supply is drastically less than the amount of petroleum-based fuel that is burned for transportation and home heating in the world.
  • It is important to note that one gallon of waste oil is not equivalent to one gallon of biodiesel
  • Although it is economically profitable to use WVO to produce biodiesel, it is even more profitable to convert WVO into other products such as soap. Therefore, most WVO that is not dumped into landfills is used for these other purposes.
  • Animal fats are similarly limited in supply, and it would not be efficient to raise animals simply for their fat. However, producing biodiesel with animal fat that would have otherwise been discarded could replace a small percentage of petroleum diesel usage.
  • Advantages of Biodiesel:

Biodiesel feedstock plants utilize photosynthesis to convert solar energy into chemical energy. The stored chemical energy is released when it is burned, therefore plants can offer a sustainable oil source for biodiesel production.

Most of the carbon dioxide emitted when burning biodiesel is simply recycling that which was absorbed during plant growth. So the net production of greenhouse gases is small. However, Biodiesel produces more NOx emissions than standard diesel fuel.

At the tailpipe, biodiesel emits 4.7% more CO2 than petroleum diesel”. However, if “biomass carbon [is] accounted for separately from fossil-derived carbon”, one can conclude that biodiesel reduces emissions of carbon monoxide (CO) by approximately 50% and carbon dioxide by 78% on a net lifecycle basis because the carbon in biodiesel emissions is recycled from carbon that was in the atmosphere, rather than the carbon introduced from petroleum that was sequestered in the earth’s crust.

Biodiesel contains fewer aromatic hydrocarbons:

benzofluoranthene: 56% reduction; Benzopyrenes: 71% reduction.

Biodiesel can reduce by as much as 20% the direct (tailpipe) emission of particulates, small particles of solid combustion products, on vehicles with particulate filters, compared with low-sulfur (<50 ppm) diesel.

Particulate emissions as the result of production are reduced by around 50%, compared with fossil-sourced diesel.

Biodiesel has a higher cetane rating than petrodiesel, which can improve performance and clean up emissions compared to crude petro-diesel (with cetane lower than 40).

Laboratory Synthesis of Bioediesel

Aim: Making Biodiesel from French fries oil

Procedure:

  • Examine the container of waste fryer oil and note its appearance. Depending upon the oil, it may also be more or less solidified, because frying oils vary widely from “lard” which is an animal fat, to lighter oils such as corn or soy oil.
  • Waste material in the used oil must be removed. For this purpose, a filter made of a piece of cloth may be used. Filter out about 200ml of the oil. Examine the filtered oil and note down its appearance.
  • Carefully pour 1 mL of the oil into a graduated cylinder. Add enough isopropanol to it to make 10 mL, cover with a piece of parafilm and invert several times to mix. Pour the resulting solution into a 25 mL Erlenmeyer flask and cover it with parafilm, too.
  • Use a small piece of pH paper to measure the pH of the solution, and note the pH in your notebook as well.
  • A solution containing 1 gram of alkali per liter of water has been made and will be put in a buret. Use this buret to add 1 mL of this alkali solution to the contents of your 25 mL Erlenmeyer, cover and mix carefully by swirling. Measure the pH with pH paper. Repeat as often as necessary to cause the pH to change to around 8 or 9. Note the total volume of alkali needed.
  • The concentration of the titrant was chosen so that the number of ml of titrant equals the number of extra grams of alkali needed to neutralize the free fatty acids. To this must be added the amount of alkali needed to catalyze the reaction.
  • If the alkali used is to be sodium hydroxide, this will be 3.5 g of NaOH per liter of oil. If potassium hydroxide is to be used, we will need 9.0 g of KOH per liter of oil.

Add the required amount of alkali.

  • Measure the amount of methanol you will need in a graduated cylinder. You’ll be assigned an amount from 10% to 20% of the oil by volume. Add that amount to a 250 mL Erlenmeyer flask and immediately cover it with a piece of parafilm so it doesn’t evaporate.
  • Carefully slide a stirring bar down the side of the flask, add the alkali from your weighing boat, and cover with the parafilm. Put the flask on the stirrer and start it mixing to dissolve the alkali. It will take a few minutes to dissolve.
  • Using a graduated cylinder, measure 200 mL of filtered oil and add it to the 250 mL flask while stirring. Re-cover with parafilm, and let it stir for 1 hour.Remove from the stirrer and pour your mix into a separatory funnel and cap. Be careful not to let the stirring bar drop into the separatory funnel. Let the mixture settle at least overnight.
  • Use the separatory funnel to drain as much of the glycerin as you can into a graduated cylinder. It tends to coat the sides of the funnel, so it may take several minutes to get it out. Note how much you have. If there is a soap layer, drain it into a separate graduated cylinder and note its volume as well. Pour the biodiesel from the top of the funnel into another graduated cylinder and note its volume.

rueckspf

Intelligent micro fine filtration

  • Use pH paper to check the pH of both the top biodiesel layer and the bottom glycerin layer. If there was a soap layer, check its pH as well.
  • Fryer oils will have a specific gravity generally around 0.94-0.96, while biodiesel will have a specific gravity in the 0.86-0.89 range. We generally consider biodiesel specific gravities above 0.9 to be incompletely transesterified. you can weigh a small amount of the biodiesel using a volumetric flask to calculate the density, and from that the specific gravity.
  • Viscosity is also an important property since most applications such as diesel engines and oil furnaces use a pump to spray the fuel into the combustion chamber. Biodiesel must have a viscosity similar to petroleum diesel to be useful in the same equipment.

Precautions

  • The chemicals should be handled with care to avoid any mishaps.
  • Sodium hydroxide and potassium hydroxide can cause chemical burns, either from the solid form or the alcohol solutions. Therefore these must be used with caution.
  • Place the esters and the glycerin in the containers provided.
  • Any excess or left over vegetable oil can be put back into the Waste Fryer Oil container.
  • Any excess alcohol or lye can be thrown away.

Result and Conclusion

The oil sample thus obtained is put in a small oil lamp. It is observed that the lamp burns well with less smoke. Therefore the synthesis of biodiesel has been completed successfully.

The biodiesel produced was found to be releasing very less smoke. Therefore it is less polluting. It can even be used in the common diesel engines. This will greatly reduce the emission of CO2 and other poisonous gases as exhaust from automobiles. Mass production of biodiesel from waste oil will also reduce the amount of waste oil that is dumped in pits causing a lot of pollution.

Making_Biodiesel[1]

BIBLIOGRAPHY

  • www.franken filtertechnik kg.com/
  • www.biodiesel.com/

You can find other Chemistry Projects here.

Avogadro Experimental Calculation – Chemistry Project

CONTENTS

INTRODUCTION 1)

USES OF AVOGADRO CONSTANT 3)

METHODS USED TO OBTAIN AVOGADRO CONSTANT 4)

PROCEDURE 8)

OBSERVATIONS 10)

PRECAUTIONS 11)

BIBLIOGRAPHY 12)

Amedeo Avogadro

Amedeo Avogadro

In chemistry and physics, the Avogadro constant (symbols: L, NA), also called Avogadro’s number, is the number of “elementary entities” (usually atoms or molecules) in one mole, that is, the number of atoms in exactly 12 grams of carbon-12.The 2006 CODATA recommended value is:

NA = 6.02214179(30) mol-1

The Avogadro constant is named after the early nineteenth century Italian scientist Amedeo Avogadro, who, in 1811, first proposed that the volume of a

1) gas at a given pressure and temperature is proportional to the number of atoms or molecules regardless of the nature of the gas. The French physicist Jean Perrin in 1909 proposed naming the constant in honour of Avogadro.

The value of the Avogadro constant was first indicated by Johann Josef Loschmidt who, in 1865, estimated the average diameter of the molecules in air by a method that is equivalent to calculating the number of particles in a given volume of gas. This latter value, the number density of particles in an ideal gas, is now called the Loschmidt constant in his honour, and is approximately proportional to the Avogadro constant.

Jean Perrin originally proposed the name “Avogadro’s number” (N) to refer to the number of molecules in one gram-molecule of oxygen. The change in name to “Avogadro constant” (NA) came with the introduction of the mole as a separate base unit in the International System of Units (SI) in 1971, which recognized amount of substance as an independent dimension of measurement. With this recognition, the Avogadro constant was no longer a pure number but a physical quantity associated with a unit of measurement, the reciprocal mole (mol−1) in SI units.

2) Because of its role as a scaling factor, the Avogadro constant provides the link between a number of useful physical constants when moving between the atomic scale and the macroscopic scale. For example, it provides the relationship between:

The gas constant R and the Boltzmann constant kB:

R = kB NA = 8.314472(15) J mol-1 K-1

The Faraday constant F and the elementary charge e:

F = NAe = 96485.3389(83) C mol-1

The Avogadro constant also enters into the definition of the unified atomic mass unit, u:

1u = Mu = 1.660538782(83) x 10-24 g

NA

where Mu is the molar mass constant.

Coulometry

Coulometry

The earliest accurate method to measure the value of the Avogadro constant was based on coulometry. The principle is to measure the Faraday constant, F,

4) which is the electric charge carried by one mole of electrons, and to divide by the elementary charge, e, to obtain the Avogadro constant.

NA = Fe

The classic experiment is that of Bowers and Davis at NIST, and relies on dissolving silver metal away from the anode of an electrolysis cell, while passing a constant electric current I for a known time t. If m is the mass of silver lost from the anode and Ar the atomic weight of silver, then the Faraday constant is given by:

F = \frac{A_{\rm r}M_{\rm u}It}{m}

Their value for the conventional Faraday constant is F90 = 96 485.39(13) C/mol, which corresponds to a value for the Avogadro constant of 6.022 1449(78) × 1023 mol−1: both values have a relative standard uncertainty of 1.3 × 10–6.

Electron mass method (CODATA)

Electron around nucleus

5) The CODATA value for the Avogadro constant is determined from the ratio of the molar mass of the electron Ar(e)Mu to the rest mass of the electron me:

N_{\rm A} = \frac{A_{\rm r}({\rm e})M_{\rm u}}{m_{\rm e}}

m_{\rm e} = \frac{2R_{\infty}h}{c\alpha^2}

The “relative atomic mass” of the electron, Ar(e), is a directly-measured quantity, and the molar mass constant, Mu, is a defined constant in the SI system. The electron rest mass, however, is calculated from other measured constants.

The main limiting factor in the precision to which the value of the Avogadro constant is known is the uncertainty in the value of the Planck constant, as all the other constants which contribute to the calculation are known much more precisely.

http://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Silicon-unit-cell-labelled-3D-balls.png/200px-Silicon-unit-cell-labelled-3D-balls.png

X Ray Electron mass method (CODATA)

 

Ball-and-stick model of the unit cell of silicon.

One modern method to calculate the Avogadro constant is to use ratio of the molar volume, Vm, to the unit cell volume, Vcell, for a single crystal of silicon:

6)

N_{\rm A} = \frac{8V_{\rm m}({\rm Si})}{V_{\rm cell}}

The factor of eight arises because there are eight silicon atoms in each unit cell.

The unit cell volume can be obtained by X-ray crystallography; as the unit cell is cubic, the volume is the cube of the length of one side. The isotope proportional composition of the sample used must be measured and taken into account.

Silicon occurs with three stable isotopes – 28Si, 29Si, 30Si – and the natural variation in their proportions is greater than other uncertainties in the measurements.

The atomic weight Ar for the sample crystal can be calculated, as the relative atomic masses of the three nuclides are known with great accuracy. This, together with the measured density ρ of the sample, allows the molar volume Vm to be found by:

V_{\rm m} = \frac{A_{\rm r}M_{\rm u}}{\rho}

where Mu is the molar mass constant. The 2006 CODATA value for the molar volume of silicon.

As of the 2006 CODATA recommended values, the relative uncertainty in determinations of the Avogadro constant by the X-ray crystal density method is 1.2 × 10–7, about two and a half times higher than that of the electron mass method.

PROCEDURE

Materials

  • Direct current source (battery or power supply)
  • Insulated wires and possibly alligator clips to connect the cells
  • 2 Electrodes (e.g., strips of copper, nickel, zinc, or iron)
  • 250-ml beaker of 0.5 M H2SO4 (sulphuric acid)
  • Water
  • Alcohol (e.g., methanol or isopropyl alcohol)
  • Small beaker of 6 M HNO3 (nitric acid)
  • Ammeter or multimeter
  • Stopwatch
  • Analytical balance capable of measuring to nearest 0.0001 gram

Obtain two copper electrodes. Clean the electrode to be used as the anode by immersing it in 6 M HNO3 in a fume hood for 2-3 seconds. Remove the electrode promptly or the acid will destroy it. Do not touch the electrode with your fingers. Rinse the electrode with clean tap water. Next, dip the electrode into a beaker of alcohol. Place the electrode onto a paper towel. When the electrode is dry, weigh it on an analytical balance to the nearest 0.0001 gram.

The apparatus looks superficially like this diagram of an electrolytic cell

Notice that we are using two beakers connected by an ammeter rather than

8) having the electrodes together in a solution. Take beaker with 0.5 M H2SO4 and place an electrode in each beaker. Before making any connections be sure the power supply is off and unplugged. The power supply is connected to the ammeter in series with the electrodes. The positive pole of the power supply is connected to the anode. The negative pin of the ammeter is connected to the anode. The cathode is connected to the positive pin of the ammeter. Finally, the cathode of the electrolytic cell is connected to the negative post of the battery or power supply. Remember, the mass of the anode will begin to change as soon as you turn the power on, so have your stopwatch ready!

You need accurate current and time measurements. The amperage should be recorded at one minute (60 sec) intervals. Be aware that the amperage may vary over the course of the experiment due to changes in the electrolyte solution, temperature, and position of the electrodes. The amperage used in the calculation should be an average of all readings. Allow the current to flow for a minimum of 1020 seconds (17.00 minutes). Measure the time to the nearest second or fraction of a second. After 1020 seconds turn off the power supply record the last amperage value and the time.

Now you retrieve the anode from the cell, dry it as before by immersing it in alcohol and allowing it to dry on a paper towel, and weigh it. If you wipe the anode you will remove copper from the surface and invalidate your work!

OBSERVATIONS

The following observations were made:

Anode mass lost: 0.3554 grams (g)
Current(average): 0.601 amperes (amp)
Time of electrolysis: 1802 seconds (s)

Remember:
one ampere = 1 coulomb/second or one amp.s = 1 coul
charge of one electron is 1.602 x 10-19 coulomb

  1. Find the total charge passed through the circuit.
    (0.601 amp)(1 coul/1amp-s)(1802 s) = 1083 coul
  2. Calculate the number of electrons in the electrolysis.
    (1083 coul)(1 electron/1.6022 x 1019coul) = 6.759 x 1021 electrons
  3. Determine the number of copper atoms lost from the anode.
    The electrolysis process consumes two electrons per copper ion formed. Thus, the number of copper (II) ions formed is half the number of electrons.
    Number of Cu2+ ions = ½ number of electrons measured
    Number of Cu2+ ions = (6.752 x 1021 electrons)(1 Cu2+ / 2 electrons)
    Number of Cu2+ ions = 3.380 x 1021 Cu2+ ions
  4. Calculate the number of copper ions per gram of copper from the number of copper ions above and the mass of copper ions produced.
    The mass of the copper ions produced is equal to the mass loss of the anode. (The mass of the electrons is so small as to be negligible, so the mass of the copper (II) ions is the same as the mass of copper atoms.)
    mass loss of electrode = mass of Cu2+ ions = 0.3554 g
    3.380 x 1021 Cu2+ ions / 0.3544g = 9.510 x 1021 Cu2+ ions/g = 9.510 x 1021 Cu atoms/g

 

  1. Calculate the number of copper atoms in a mole of copper, 63.546 grams.
    Cu atoms/mole of Cu = (9.510 x 1021 copper atoms/g copper)(63.546 g/mole copper)
    Cu atoms/mole of Cu = 6.040 x 1023 copper atoms/mole of copper
    This is  my measured value of Avogadro’s number!
  2. Calculate percent error.
    Absolute error: |6.02 x 1023 – 6.04 x 1023 | = 2 x 1021
    Percent error: (2 x 10 21 / 6.02 x 10 23)(100) = 0.3 %

Precautions

  • The chemicals should be handled with care to avoid any mishaps.
  • Do not switch on the battery before you have setup the entire circuit.
  • Be accurate while starting and stopping the stopwatch.
  • Do not wipe the anode.

BIBLIOGRAPHY

  1. http://www.iupac.org/goldbook/A00543.pdf
  2. http://gemini.tntech.edu/%7Etfurtsch/scihist/avogadro.htm
  3. http://www.americanscientist.org/issues/pub/2007/2/an-exact-value-for-avogadros-number
  4. http://www.inrim.it/Nah/Web_Nah/home.htm

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Antacid for neutralizing stomach acid – Chemistry Project

 

S.No. Contents II Page No.
I. Objective
II. Introduction
III. Experiment
IV. Material required
V. Procedure
VI. Observation
VII. Result
VIII. Precaution
IX. Bibliography

OBJECTIVE

The purpose of this experiment was to determine which antacid could neutralize the most stomach acid.

I became interested in this idea when I saw some experiments on medicines and wanted to find out some scientific facts about medicines.

The information gained from this experiment will help people know which antacid they should look for in the stores. It will also let them know which antacid will give them the most comfort. This could also save consumers money and provide better health.

INTRODUCTION

Digestion in the stomach results from the action of the gastric fluid, which includes secretions of digestive enzymes, mucus, and hydrochloric acid. The acidic environment of the stomach makes it possible for inactive forms of digestive enzymes to be converted into active forms (i.e. pepsinogen into pepsin), and acid is also needed to dissolve minerals and kill bacteria that may enter the stomach along with food. However, excessive acid production (hyperacidity) results in the unpleasant symptoms of heartburn and may contribute to ulcer formation in the stomach lining. Antacids are weak bases (most commonly bicarbonates, hydroxides, and carbonates) that neutralize excess stomach acid and thus alleviate symptoms of heartburn. The general neutralization reaction is:

Antacid (weak base) + HCl (stomach acid) —> salts + H20 + C02

The hydrochloric acid solution used in this experiment (0.1 M) approximates the acid conditions of the human stomach, which is typically 0.4 to 0.5% HQ by mass (pH ~ 1).Antacids help people who have or get heartburn.

ACIDS

Acids are a group of chemicals, usually in liquid form. They can be recognized by their sour taste and their ability to react with other substances. Acids are confirmed as an acid by their pH. The pH of acids ranges from 0-6.9 (below 7). The two main acids are: mineral acid and organic acid. The three well known acids that are sulphuric acid (H2S04), nitric acid (HN03), and hydrochloric acid (HCl).

STOMACH ACID

Stomach acid is very dangerous. If a person was to have an ulcer and the stomach acid was to escape it would irritate their other organs. Stomach acid is highly acidic and has a pH of 1.6. Stomach acid is hydrochloric acid produced by the stomach. If there is too much stomach acid it can cause heartburn. Heartburn is when stomach acid is produced in abnormal amounts or location. One of the symptoms of heartburn is a burning feeling in the chest or abdomen.

SOME FOODS CONTAINING ACIDS

Almost all foods and drinks and even medicines have ingredients that are different acids. Here are some examples: Aspirin (acetylsalicylic acid), Orange juice (ascorbic acid/Vitamin C), Sour Milk (lactic acid), Soda Water (carbonic acid), Vinegar (acetic acid), Apples (malic acid), and Spinach (oxalic acid).

ANTACID

An antacid is any substance that can neutralize an acid. All antacids are bases. A base is any substance that can neutralize an acid. The pH of a base is 7.1-14(above 7). All antacids have chemical in them called a buffer. When an antacid is mixed with an acid the buffer tries to even out the acidity and that is how stomach acid gets neutralized. In an antacid it is not the name brand that tells how well it works it is something called an active ingredient. Not all antacids have a different active ingredient. Some have one of the same active ingredients and some have all of the same active ingredients. Almost all the antacids that have the same active ingredient work the same amount as the other. The active ingredient of most of the antacids is bases of calcium, magnesium, aluminium.

ACTION MECHANISM

Antacids perform neutralization reaction, i.e. they buffer gastric acid, raising the pH to reduce acidity in the stomach. When gastric hydrochloric acid reaches the nerves in the gastrointestinal mucosa, they signal pain to the central nervous system. This happens when these nerves are exposed, as in peptic ulcers. The gastric acid may also reach ulcers in the oesophagus or the duodenum.

Other mechanisms may contribute, such as the effect of aluminium ions inhibiting smooth muscle cell contraction and delaying gastric emptying.

Antacids are commonly used to help neutralize stomach acid. Antacids are bases with a pH above 7.0 that chemically react with acids to neutralize them. The action of antacids is based on the fact that a base reacts with acid to form salt and water.

INDICATIONS

Antacids are taken by mouth to relieve heartburn, the major symptom of gastro oesophageal reflux disease, or acid indigestion. Treatment with antacids alone is asymptotic and only justified for minor symptoms. Peptic ulcers may require H2– receptor antagonists or proton pump inhibitors.

The usefulness of many combinations of antacids is not clear, although the combination of magnesium and aluminium salts may prevent alteration of bowel habits.

SIDE EFFECTS

  • Aluminium hydroxide: may lead to the formation of insoluble aluminium phosphate complexes, with a risk for hypophosphate and osteomalacia. Although aluminium has a low gastrointestinal absorption, accumulation may occur in the presence of renal insufficiency. Aluminium containing drugs may cause constipation.
  • Magnesium hydroxide: has a laxative property. Magnesium may accumulate in patients with renal failure leading to hypo magnesia, with cardiovascular and neurological complications.
  • Calcium: compounds containing calcium may increase calcium output in the urine, which might be associated to renal stones. Calcium salts may cause constipation.
  • Carbonate: regular high doses may cause alkalosis, which in turn may result in altered excretion of other drugs, and kidney stones.

PROBLEMS WITH REDUCED STOMACH ACIDITY

Reduced stomach acidity may result in an impaired ability to digest and absorb certain nutrients, such as iron and the B vitamins. Since the low pH of the stomach normally kills ingested bacteria, antacids increase the vulnerability to infection. It could also result in the reduced bioavailability of some drugs. For example, the bioavailability of ketocanazole (antifungal), is reduced at high intragastric pH (low acid content).

EXPERIMENT

The constants in this study were:

–   Type of acid

–   Consistency of procedures

The variables in the study were:

-Different types of antacid used

The responding variable was:

–  The amount of stomach acid each antacid could neutralize measured in ml.

MATERIAL REQUIRED

  • Burette
  • Pipette
  • Titration flask
  • Measuring flask
  • Beaker
  • Weighing machine
  • Concentrated Sulphuric acid
  • Methyl Orange
  • Antacid samples

PROCEDURE

  • Prepare half litre of N/10 HCl solution by diluting 10 ml of the concentrated acid to 1 litre.
  • Prepare N/10 sodium carbonate solution by weighing exactly 1.325 g of anhydrous sodium carbonate and then dissolving it in water to prepare exactly 0.25 litre of solution.
  • Standardize the HCl solution by titrating it against the standard sodium carbonate solution using methyl orange as indicator.
  • Take 20 ml of standardized HCl in the conical flask, use methyl orange as indicator and see the amount of base used for neutralization.
  • Powder the various sample of antacids tablets and weigh 10 mg of each.
    • Take 20 ml of standardized HCl solution in the conical flask; add the weighed samples to it.
    • Add two drops of methyl orange and warm the flask till most of the powder dissolves. Filter off the insoluble material.
    • Titrate the solution against the standardized Na2C03 solution till a permanent red tinge appears.
    • Note the amount of base used for titration and note the reduction in the amount of base used.
    • Repeat the experiment with different antacids.

OBSERVATIONS

Volume of N/10 sodium carbonate solution taken—20.0 ml

S. No. Initial burette Final burette Volume of acid
readings readings used (in ml)
1 0.0 ml 15 ml 15.0
2 0.0 ml 14 ml 14.0
3 0.0 ml 15 ml 15.0

Concordant reading—15.0 ml Applying normality equation

N1V1(acid) N2V2(base)

N (15) — (1/10) 20

Normality of HCl solution, N1 — 0.133 N

2. Neutralization of standardized HCl solution used

3. Analysis of antacid tablets

Weight of the antacid tablet powder— 10 mg Volume of HCl solution added— 20.0 ml

S. No. Antacid Initial reading of burette Final reading of burette Volume of Na2C03
1 Gelusil 0.0 ml 15.0 ml 15 ml
2 Aciloc 150 0.0 ml 22.0 ml 22 ml
3 Fantac 20 0.0 ml 25.0 ml 25 ml
4 Pantop 20 0.0 ml 20.0 ml 20 ml
5 Ocid 10 0.0 ml 7.0 ml 7 ml

RESULT

The most effective antacid out of the taken samples is acid 10.

PRECAUTIONS

  • All apparatus should be clean and washed properly.
  • Burette and pipette must be rinsed with the respective solution to be put in them.
  • Air bubbles must be removed from the burette and jet.
  • Last drop from the pipette should not be removed by blowing.
  • The flask should not be rinsed with any of the solution, which are being titrated.

Bibliography

  • Website : http:/ /www.encarta.com
  • NCERT Chemistry-12
  • Comprehensive Practical Chemistry -12

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Analysis Of Vegetables And Fruit Juices – Chemistry Project

 

S.No. Contents II Page No.
I. Introduction  
II. Material Requirement  
III. Experimental Procedure  
IV. Conclusion  
V. Bibliography  

INTRODUCTION

Fruits and vegetable are always a part of balanced diet. That means fruits vegetables provide our body with the essential nutrients, i.e. Carbohydrates, proteins, vitamins and minerals. Again their presence in these is being indicated by some of our general observations, like -freshly cut apples become reddish black after some time. Explanation for it is that iron present in apple gets oxidised to iron oxide. So, we can conclude that fruits and vegetables contain complex organic compounds, for e.g., anthocin, chlorophyll, esters(flavouring compounds), carbohydrates, vitamins and can be tested in any fruits or vegetable by extracting out its juice and then subtracting it to various tests which are for detection of different classes of organic compounds. Detection of minerals in vegetables or fruits means detection of elements other than carbon, hydrogen and oxygen.

MATERIAL REQUIRED

  • Test Tubes
  • Burner
  • Litmus paper
  • Laboratory reagents
  • Various fruits
  • Vegetables juices

CHEMICAL REQUIREMENTS

  • pH indicator
  • Iodine solution
  • Fehling solution A and Fehling solution B
  • Ammonium chloride solution
  • Ammonium hydroxide
  • Ammonium oxalate
  • Potassium sulphocyanide solution

PROCEDURE

The juices are made dilute by adding distilled water to it, in order to remove colour and to make it colourless so that colour change can be easily watched and noted down. Now test for food components are taken down with the solution.

TEST, OBSERVATION & INFERENCE

Test Observation Inference
ORANGE TEST:
Test for acidity:
Take 5ml of orange juice in a test tube and dip a pH paper in it. If pH is less than 7 the juice is acidic else the juice is basic. The pH comes out to be 6. Orange juice is acidic.
Test for Starch:
Take 2 ml of juice in a test tube and add few drops of iodine solution. It turns blue black in colour than the starch is present. Absence of blue black in colour. Orange juice is acidic.
Test for Carbohydrates (FEHLING’S TEST):
Take 2 ml of juice and 1 ml of Fehling solution A & B and boil it. Red precipitates indicates the presence of producing sugar like maltose, glucose , fructose & Lactose. No red coloured precipitates obtained. Carbohydrates absent.
Test for Iron:
Take 2 ml of juice add drop of conc. Nitric acid. Boil the solution cool and add 2-3 drops of potassium sulphocyanide solution .Blood red colours shows the presence of iron. Absence of blood red colour. Iron is absent.
Test for Calcium:
Take 2 ml of juice add Ammonium chloride and ammonium hydroxide solution. Filter the solution and to the filtrate add 2 ml of Ammonium Oxalate solution. white ppt or milkiness indicates the presence of calcium. Yellow precipitate is obtained. Calcium is present.

CONCLUSION

From the table given behind it can be conducted that most of the fruits & vegetable contain carbohydrate & vegetable contain carbohydrate to a small extent. Proteins are present in small quantity. Therefore one must not only depend on fruits and vegetables for a balance diet.

BIBLIOGRAPHY

NCERT Chemistry Part 1 & Part 2

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Amount of Acetic Acid In Vinegar – Chemistry Project

Measuring the Amount of Acetic Acid In Vinegar

 

S.No. Contents II Page No.
I. Introduction  
II. Materials And Equipments  
III. Theory  
V. Experimental Procedure
VI. Experiment 1  
VII. Experiment 2  
VIII. Experiment 3  
IX. Result  
X Precaution  
XI. Bibliography  

Introduction

Vinegar is a solution made from the fermentation of ethanol (CH3CH2OH), which in turn was previously fermented from sugar. The fermentation of ethanol results in the production of acetic acid (CH3COOH). There are many different types of vinegar, each starting from a different original sugar source (e.g., rice, wine, malt, etc.). The amount of acetic acid in vinegar can vary, typically between 4 to 6% for table vinegar, but up to three times higher (18%) for pickling vinegar.

In this project, we will determine the amount of acid in different vinegar using titration, a common technique in chemistry. Titration is a way to measure the unknown amount of a chemical in a solution (the titrant) by adding a measured amount of a chemical with a known concentration (the titrating solution). The titrating solution reacts with the titrant, and the endpoint of the reaction is monitored in some way. The concentration of the titrant can now be calculated from the amount of titrating solution added, and the ratio of the two chemicals in the chemical equation for the reaction.

To measure the acidity of a vinegar solution, we can add enough hydroxyl ions to balance out the added hydrogen ions from the acid. The hydroxyl ions will react with the hydrogen ions to produce water. In order for a titration to work, we need three things:

  1. a titration solution (contains hydroxyl ions with a precisely known concentration),
  2. a method for delivering a precisely measured volume of the titrating solution, and
  3. a means of indicating when the endpoint has been reached.

For the titrating solution, we’ll use a dilute solution of sodium hydroxide (NaOH). Sodium hydroxide is a strong base, which means that it dissociates almost completely in water. So for every NaOH molecule that we add to the solution, we can expect to produce a hydroxyl ion.

To dispense an accurately measured volume of the titrating solution, we will use a burette. A burette is a long tube with a valve at the bottom and graduated markings on the outside to measure the volume contained in the burette. The burette is mounted on a ring stand, directly above the titrant solution (as shown in the picture).

Solutions in the burette tend to creep up the sides of the glass at the surface of the liquid. This is due to the surface tension of water. The surface of the liquid thus forms a curve, called a meniscus. To measure the volume of the liquid in the burette, always read from the bottom of the meniscus.

In this experiment, we will use an indicator solution called phenolphthalein. Phenolphthalein is colourless when the solution is acidic or neutral. When the solution becomes slightly basic, phenolphthalein turns pinkish, and then light purple as the solution becomes more basic. So when the vinegar solution starts to turn pink, we know that the titration is complete.

Materials and Equipment

To do this experiment we will need the following materials and equipment:

.     Vinegar, three different types.

.     Distilled water

.     Small funnel

.     0.5% Phenolphthalein solution in alcohol (pH indicator solution)

.     0.1 M sodium hydroxide solution

.     125 mL Conical flask

.     25 or 50 mL burette

.     10 mL graduated cylinder

.     Ring stand

.     Burette clamp

Theory

Required amount of sodium hydroxide (NaOH) can be calculated using the following formula:

W = Molarity x Molar mass x Volume(cm )
=
1000

Molar mass of NaOH = 40 g/mol =   0.5 x 40 x 500 ~        1000 =    10 g

The acetic acid content of a vinegar may be determined by titrating a vinegar sample with a solution of sodium hydroxide of known molar concentration (Molarity).

CH3COOH(aq) + NaOH(aq)     CH3COONa(aq) + H2O(l) (acid) + (base) — > (salt) + (water)

At the end point in the titration stoichiometry between the both solution lies in a 1:1 ratio.

MCH3COOHVCH3COOH      1

MNaOHVNaOH                         1

Strength of acid in vinegar can be determined by the following formula:

Strength of acetic acid = MCH COOH x 60

Indicator:- Phenolphthalein End Point:- Colourless to pink

Experimental Procedure

Performing the Titration

  1. Pour 1.5 ml of vinegar in an Conical flask.
    1. Add distilled water to dissolve the vinegar so that the volume of the solution becomes 20 mL.
    2. Add 3 drops of 0.5% phenolphthalein solution.
      1. Use the burette clamp to attach the burette to the ring stand. The opening at the bottom of the burette should be just above the height of the Conical flask we use for the vinegar and phenolphthalein solution.
      2. Use a funnel to fill the burette with a 0.1 M solution of sodium hydroxide.
      3. Note the starting level of the sodium hydroxide solution in the burette. Put the vinegar solution to be titrated under the burette.
      4. Slowly drip the solution of sodium hydroxide into the vinegar solution. Swirl the flask gently to mix the solution, while keeping the opening underneath the burette.
      5. At some point we will see a pink colour in the vinegar solution when the sodium hydroxide is added, but the colour will quickly

disappear as the solution is mixed. When this happens, slow the burette to drop-by-drop addition.

  1. When the vinegar solution turns pink and remains that colour even with mixing, the titration is complete. Close the tap (or pinch valve) of the burette.
  2. Note the remaining level of the sodium hydroxide solution in the burette. Remember to read from the bottom of the meniscus.
  3. Subtract the initial level from the remaining level to figure out how much titrating solution we have used.
  4. For each vinegar that we test, repeat the titration at least three times.

EXPERIMENT – 1

I.   Take the household vinegar in the conical flask and do the titration with sodium hydroxide (NaOH) as mentioned.

OBSERVATIONS

S.no Volume of vinegar solution Burette Reading Volume of NaOH solution used
Initial (in mL) Final (in mL)
1. 20 0 27 27
2. 20 0 27 27
3. 20 0 27 27

Concordant volume = 27 mL

CALCULATIONS

We know that,

M CH 3 COOH VCH 3 COOH _ M NaOH VNaOH Continue reading “Amount of Acetic Acid In Vinegar – Chemistry Project”

Adulterants in Food – Chemistry Project

Study of  the Adulterants in Food

 

S.No. Contents Page No.
I. Objective
II. Theory
III. Experiment 1
IV. Experiment 2
V. Experiment 3
VI. Result
VII. Conclusion
VIII. Bibliography

Objective

The Objective of this project is to study some of the common food adulterants present in different food stuffs.

Adulteration in food is normally present in its most crude form; prohibited substances are either added or partly or wholly substituted. Normally the contamination/adulteration in food is done either for financial gain or due to carelessness and lack in a proper hygienic condition of processing, storing, transportation and marketing. This ultimately results that the consumer is either cheated or often become a victim of diseases. Such types of adulteration are quite common in developing countries or backward countries. It is equally important for the consumer to know the common adulterants and their effect on health.

THEORY

The increasing number of food producers and the outstanding amount of import foodstuffs enables the producers to mislead and cheat consumers. To differentiate those who take advantage of legal rules from the ones who commit food adulteration is very difficult. The consciousness of consumers would be crucial. Ignorance and unfair market behaviour may endanger consumer health and misleading can lead to poisoning. So we need simple screening, tests for their detection.

In the past few decades, adulteration of food has become one of the serious problems. Consumption of adulterated food causes serious diseases like cancer, .diarrhoea., , .asthma., .ulcers., etc. Majority of fats, oils and butter are paraffin wax, castor oil and hydrocarbons. Red chilli powder is mixed with brick powder and pepper is mixed with dried papaya seeds. These adulterants can be easily identified by simple chemical tests.

Several agencies .have been set up by the Government of India to remove adulterants from food stuff.

AGMARK – Acronym for agricultural marketing. This organization certifies food products for their quality. Its objective is to promote the Grading and Standardization of agricultural and allied commodities.

EXPERIMENT 1

AIM

To detect the presence of adulterants in fat, oil and butter.

REQUIREMENTS

Test-tube, acetic anhydride, conc. H2SO4, acetic acid, conc. HNO3.

PROCEDURE

Common adulterants present in ghee and oil are paraffin wax, hydrocarbons, dyes and argemone oil. These are detected as follows :

(i)           Adulteration of paraffin wax and hydrocarbon in vegetable ghee
Heat small amount of vegetable ghee with acetic anhydride. Droplets
of oil floating on the surface of unused acetic anhydride indicates the
presence of wax or hydrocarbons.

(ii)          Adulteration of dyes in fat

Heat 1mL of fat with a mixture of 1mL of conc. sulphuric acid and 4mL of acetic acid. Appearance of pink or red colour indicates presence of dye in fat.

(iii)        Adulteration of argemone oil in edible oils

To small amount of oil in a test-tube, add few drops of conc. HNO3 and shake. Appearance of red colour in the acid layer indicates presence of argemone oil.

EXPERIMENT 2

AIM

To detect the presence of adulterants in sugar

REQUIREMENTS

Test-tubes, dil. HCl.

PROCEDURE

Sugar is usually contaminated with washing soda and other insoluble substances which are detected as follows :

(i)           Adulteration of various insoluble substances in sugar

Take small amount of sugar in a test-tube and shake it with little water. Pure sugar dissolves in water but insoluble impurities do not dissolve.

(ii)         Adulteration of chalk powder, washing soda in sugar

To small amount of sugar in a test-tube, add few drops of dil. HCl. Brisk effervescence of CO2 shows the presence of chalk powder or washing soda in the given sample of sugar.

EXPERIMENT 3

AIM

To detect the presence of adulterants in samples of chilli powder, turmeric powder and pepper

REQUIREMENTS

Test-tubes, conc. HCl, dil. HNO3, KI solution

PROCEDURE

Common adulterants present in chilli powder, turmeric powder and pepper are red coloured lead salts, yellow lead salts and dried papaya seeds respectively. They are detected as follows :

(i)           Adulteration of red lead salts in chilli powder

To a sample of chilli powder, add dil. HNO3. Filter the solution and add 2 drops of potassium iodide solution to the filtrate. Yellow ppt. indicates the presence of lead salts in chilli powder.

(ii)         Adulteration of yellow lead salts to turmeric powder

To a sample of turmeric powder add conc. HCl. Appearance of magenta colour shows the presence of yellow oxides of lead in turmeric powder.

(iii)        Adulteration of brick powder in red chilli powder

Add small amount of given red chilli powder in beaker containing water. Brick powder settles at the bottom while pure chilli powder floats over water.

(iv)        Adulteration of dried papaya seeds in pepper

Add small amount of sample of pepper to a beaker containing water and stir with a glass rod. Dried papaya seeds being lighter float over water while pure pepper settles at the bottom.

RESULT

EXPERIMENT PROCEDURE OBSERVATION
Adulteration of paraffin wax and hydrocarbon in vegetable ghee. Heat small amount of vegetable ghee with acetic anhydride. Droplets of oil floating on the surface of unused acetic anhydride indicate the presence of wax or hydrocarbon Appearance of oil floating on the surface.
Adulteration of dyes in fat Heat 1mL of fat with a mixture of 1mL of conc. H2SO4 and 4mL of acetic acid. Appearance of pink colour.
Adulteration of argemone oil in edible oils To small amount of oil in a test tube, add few drops of conc. HNO3 & shake. No red colour observed
Adulteration of various insoluble substances in sugar. Take small amount of sugar in a test tube and shake it with little water. Pure sugar dissolves in water but insoluble impurities do not dissolve.
Adulteration of chalk powder, washing soda in sugar. To small amount of sugar in a test tube, add a few drops of dil. HCl. No brisk effervescence

observed.

Adulteration of yellow lead salts to turmeric powder. To sample of turmeric powder, add conc. HCl. Appearance of magenta colour.
Adulteration of red lead salts in chilli powder. To a sample of chilli powder, add dil. HNO3. Filter the solution and add 2 drops of KI solution to the filtrate. No yellow ppt.
Adulteration of brick powder in chilli powder. Add small amount of given red chilli powder in a beaker containing water. Brick powder settles at the bottom while pure chilli powder floats over water.
Adulteration of dried papaya seeds in pepper. Add small amount of sample of pepper to beaker containing water and stir with a glass rod. Dried papaya seeds being lighter float over water while pure pepper settles at the bottom.

CONCLUSION

Selection of wholesome and non-adulterated food is essential for daily life to make sure that such foods do not cause any health hazard. It is not possible to ensure wholesome food only on visual examination when the toxic contaminants are present in ppm level. However, visual examination of the food before purchase makes sure to ensure absence of insects, visual fungus, foreign matters, etc. Therefore, due care taken by the consumer at the time of purchase of food after thoroughly examining can be of great help. Secondly, label declaration on packed food is very important for knowing the ingredients and nutritional value. It also helps in checking the freshness of the food and the period of best before use. The consumer should avoid taking food from an unhygienic place and food being prepared under unhygienic conditions. Such types of food may cause various diseases. Consumption of cut fruits being sold in unhygienic conditions should be avoided. It is always better to buy certified food from a reputed shop.

BIBLIOGRAPHY

  • NCERT CHEMISTRY XII
  • ENCARTA ENCYCLOPEDIA

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Chemistry

Sample Certificate
Sample Acknowledgment

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