AIM- To compare the solubility of some common salts in water?
Objective
The goal of this project is to measure the solubilities of some common
chemicals: table salt (NaCl), Epsom salts (MgSO4), and sugar
(sucrose, C12H22O11).
Introduction
A good part of the substances we deal with in daily life, such as milk,
gasoline, shampoo, wood, steel and air are mixtures. When the
mixture is homogenous, that is to say, when its components are
intermingled evenly, it is called a solution. There are various types of
solutions, and these can be categorized by state (gas, liquid, or solid).
The chart below gives some examples of solutions in different states.
Many essential chemical reactions and natural processes occur in
liquid solutions, particularly those containing water (aqueous solutions)
because so many things dissolve in water. In fact, water is sometimes
referred to as the universal solvent. The electrical charges in water
molecules help dissolve different kinds of substances. Solutions form
when the force of attraction between solute and solvent is greater than
the force of attraction between the particles in the solute. Two
examples of such important processes are the uptake of nutrients by
plants, and the chemical weathering of minerals. Chemical weathering
begins to take place when carbon dioxide in the air dissolves in
rainwater. A solution called carbonic acid is formed. The process is
then completed as the acidic water seeps into rocks and dissolves
underground limestone deposits. Sometimes, the dissolving of soluble
minerals in rocks can even lead to the formation of caves.
Types of Solutions
Example
State of Solute
State of Solvent
State of Solution
Air, natural gas
gas
gas
gas
Alcohol in water, antifreeze
liquid
liquid
liquid
Brass, steel
solid
solid
solid
Carbonated water, soda
gas
liquid
liquid
Sea water, sugar solution
solid
liquid
liquid
Hydrogen in platinum
gas
solid
solid
If one takes a moment to consider aqueous solutions, one quickly
observes that they exhibit many interesting properties. For example,
the tap water in your kitchen sink does not freeze at exactly 0°C. This
is because tap water is not pure water; it contains dissolved solutes.
Some tap water, commonly known ashard water, contains mineral
solutes such as calcium carbonate, magnesium sulfate, calcium
chloride, and iron sulfate. Another interesting solution property is
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
exhibited with salt and ice. Have you ever had the chore of throwing
salt on an icy sidewalk? When the ice begins to melt, the salt dissolves
in the water and forms salt water. What happens to the freezing point
of water when salt is added to it? Even some organisms have evolved
to survive freezing water temperatures with natural "antifreeze."
Certain artic fish have blood containing a high concentration of a
specific protein. This protein behaves like a solute in a solution and
lowers the freezing point of the blood. Going to the other end of the
spectrum, one can also observe that the boiling point of a solution is
affected by the addition of a solute. Do eggs cook faster or slower
when salt is added to the pot of water? These two properties, namely
freezing-point depression and boiling-point elevation, are
called colligative properties (properties that depend on the number of
molecules, but not on their chemical nature). Exploring these
properties and others of aqueous solutions are just some of the many
ways that you could expand the scope of this project.
Finally, if you enjoy learning about solutions or other areas of
chemistry, consider a career in the physical sciences. One example is
working as ananalytical chemist. Such chemists analyze the chemical
composition of substances. They conduct many experiments to identify
special characteristics of substances for a wide variety of reasons.
Perhaps they are charged with testing municipal drinking water for its
purity, or perhaps they must test a forensic sample for evidence in a
trial. Whatever the reason, it is challenging work that requires precision
and creative thought.
In this project you will measure the aqueous solubility of some
common household chemicals: table salt (NaCl), Epsom salts
(MgSO4), and sugar (sucrose, C12H22O11). How much of each chemical
can dissolve in a given volume of water?
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:












Solution
Solute
Solvent
Soluble vs. insoluble
Chemical structure of water
Polar molecule
Force of attraction
Concentration of a solution
Dilute vs. concentrated
Sodium chloride (NaCl)
Magnesium sulfate (MgSO4)
Sucrose (C12H22O11)
Questions

What is a saturated solution?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com

What is the difference between a saturated solution and an
unsaturated solution?
Bibliography




Any basic physical science text will have a chapter on solutions or
solubility. Begin by reading a chapter on basic solution chemistry,
such as Chapter 4 in:
Haber-Schaim, U., R. Cutting, and H. G. Kirksey, 1999. Introductory
Physical Science, seventh edition, Belmont, MA: Science
Curriculum, Inc. (ISBN: 1-882057-18-X).
The Chem4Kids website is a good reference for basic chemistry
concepts. Here is a link to their webpage on solutions:
Andrew Rader Studios, 1997–2007. "Chem4Kids.com: Matter:
Solutions," Chem4Kids.com [accessed October 3,
2007]http://www.chem4kids.com/files/matter_solution.html.
This website has a collection of demonstration videos illustrating
various properties of solutions:
Maynard, J.H., 1998–2000. "General Chemistry Demonstrations:
Properties of Solutions," University of Wisconsin-Madison,
Chemistry Department, Demonstration Lab [accessed October 3,
2007]http://genchem.chem.wisc.edu/demonstrations/Gen_Chem_P
ages/11solutionspage/solutionsmain.htm.
The experimental procedure is based on:
o Gardner, R., 1999. Science Projects About Kitchen Chemistry.
Berkeley Heights, NJ: Enslow Publishers.
o Stretton, T., 2004. "Solubility of Compounds," Tom Stretton's
Chemistry Pages, Upper Canada District School Board
[accessed October 3, 2007]
http://www.ucdsb.on.ca/tiss/stretton/CHEM2/compound_solubi
lities.html.
o CBSE Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:











Distilled water
Metric liquid measuring cup (or graduated cylinder)
Three clean glass jars or beakers
Non-iodized table salt (NaCl)
Epsom salts (MgSO4)
Sugar (sucrose, C12H22O11)
Disposable plastic spoons
Thermometer
Three shallow plates or saucers
Oven
Electronic kitchen balance (accurate to 0.1 g)
Experimental Procedure
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Do your background research so that you are familiar with the terms,
concepts, and questions, above.
Determining Solubility: Method 1
1. Measure 100 mL of distilled water and pour into a clean, empty
beaker or jar.
2. Use the kitchen balance to weigh out the suggested amount (see
below) of the solute to be tested.
a. 50 g Non-iodized table salt (NaCl)
b. 50 g Epsom salts (MgSO4)
c. 250 g Sugar (sucrose, C12H22O11)
3. Add a small amount of the solute to the water and stir with a clean
disposable spoon until dissolved.
4. Repeat this process, always adding a small amount until the solute
will no longer dissolve.
5. Weigh the amount of solute remaining to determine how much was
added to the solution. Save your saturated solutions for the second
method.
Determining Solubility: Method 2
1. Label the underside of each saucer with tape, one for each solution.
2. Weigh the empty saucer and record the weight.
3. Pour in 10–15 mL of the appropriate saturated solution
(corresponding to the label on the saucer).
4. Weigh the saucer + solution and record the weight.
5. Repeat steps 2–4 for each of the three solutions.
6. Put the saucers in a warm place (e.g., an oven on low heat) and
allow the water to evaporate.
7. Re-weigh the saucers + dry crystals.
a. Tip: make sure all the water has evaporated by weighing each
saucer several times, with an interval back in the oven in
between, to make sure the weight is no longer changing.
Analyzing Your Results
1. To make sure that your results are reproducible, you should repeat
your solubility experiment at least three separate times for each
chemical.
2. For each solubility determined by Method 1, you will have the
original volume of water, the total mass of the solute, and the
remaining mass of the solute. You can calculate how much of the
solute was dissolved.
3. For each solubility determination by Method 2, you will have the
mass of the dry solid after evaporation, and the mass of the original
solution. You can calculate the mass of the water that evaporated.
4. Calculate the average solubility, in grams of solute per 100 mL of
water, as determined by each method.
5. More advanced students should also calculate the standard
deviation of the solubility, as determined by each method.
6. Compare the results of the two methods.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
7. Compare your results to published solubilities for the three
chemicals.
Variations



Let's say that instead of starting with pure water, you tried to
dissolve Epsom salts (MgSO4) in a saturated solution of NaCl. Do
you think this would work? How much MgSO4 would you expect to
dissolve? Would it be more, less or the same amount as in an equal
volume of distilled water? Design an experiment to find out.
You could also try the experiment above with the other five pair-wise
combinations of the three chemicals.
Another variation you could try is an experiment on the how fast
solutes dissolve. What can you do to increase the rate at which a
solute dissolves in a solvent? How much more quickly does the
solute dissolve, compared to when the solute is simply added to the
solvent?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects {Chemistry}~Charles's
Law: Volume vs. Temperature of a Gas at
Constant Pressure
Objective
The goal of this project is to measure the relationship between the
volume of a gas and its temperature, when the pressure of the gas is
held constant.
Introduction
This is a modern version of a classic experiment by Jacques Charles
(who was also interested in flying balloons). Charles studied the
volume of a sample of air—sealed in a glass tube with a U-shaped
curve—as he systematically changed the temperature by immersing
the tube in a water bath. The air was trapped by a column of mercury,
added to the open end of the tube. By changing the amount of mercury
in the tube, Charles could maintain a constant pressure on the trapped
air as the temperature was changed. Charles's apparatus was an
example of a manometer, a device used to measure pressure.
You can learn more about how manometers work, and even run a
simulated Charles's Law experiment by visiting the Chemistry Applet
website (see Bibliography). This would be excellent preparation for
doing the experiment on your own, so we highly recommend it. Note:
to calculate the volume of gas in the applets, you will need to know
that the inside diameter of the applet's manometer tube is 4.286
cm.
You can repeat Charles's experiments for yourself with an
inexpensive, modern apparatus based on a disposable plastic syringe
and a water bath. (Mercury is a dangerous neurotoxin, so we'll avoid
working with it.)
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:






pressure,
volume,
Charles's Law,
ideal gas,
atmospheric pressure,
manometer,
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


kelvins,
absolute zero.
Questions


What assumption is made about the pressure of the gas in this
experiment?
What is the relationship between the degrees Celsius and kelvins?
Bibliography


Here are the Chemistry Applet webpages mentioned in the
Introduction. These will really help your understanding of Charles's
Law if you take the time to do the virtual experiments! To calculate
the volume of gas in the applets, you will need to know that the
inside diameter of the applet's manometer tube is 4.286 cm.
o Blauch, D., 2004. "Gas Laws: Pressure", Department of
Chemistry, Davidson College. [accessed January 23,
2006]http://www.chm.davidson.edu/ChemistryApplets/GasLaw
s/Pressure.html,
o Blauch, D., 2004. "Gas Laws: Charles's Law", Department of
Chemistry, Davidson College. [accessed January 23,
2006]http://www.chm.davidson.edu/ChemistryApplets/GasLaw
s/CharlesLaw.html.
The Sizes.com website has an exhaustive index of units of
measure, including both degrees Celsius and kelvins:
o Editor, Sizes.com, 2000. "centigrade and Celsius temperature
scales" [accessed January 23,
2006]http://www.sizes.com/units/temperature_centigrade.htm
o Editor, Sizes.com, 2000. "kelvin" [accessed January 23,
2006]http://www.sizes.com/units/temperature_kelvin.htm
o CBSE Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:






35 ml syringe (available, for example, from Science First ("Gas Law
Demonstrator Kit", Science First, Buffalo,
NY.http://www.sciencefirst.com/vw_prdct_mdl.asp?prdct_mdl_cd=3
0170),
a homemade clamp to hold syringe underwater, which can be made
with:
o two sturdy chopsticks (or two sturdy wood dowels) longer than
the diameter of your cooking pot,
o two rubber bands,
o a weight (e.g., a can of soup);
small piece of wire,
thermometer (calibrated in °C, range at least 0–100°C),
water,
ice,
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


cooking pot, deeper than syringe is tall,
stove.
Experimental Procedure
Experimental Apparatus
Diagram showing how to set up syringe. The thin wire between the plunger tip and the inner syringe
wall allows air to escape from in front of the plunger in order to equalize pressure. It is removed
before starting the experiment. Diagram adapted from Gabel, 1996.
1.
2.
3.
4.
5.
6.
7.
Before starting the experiment, do your background research so that
you are knowledgeable about the terms, concepts and questions,
above.
With the plunger removed from the syringe, seal the tip of the
syringe with a tight-fitting cap. If a suitable cap is not available, you
can try epoxy or silicone sealant. Allow the epoxy or silicone the
recommended curing time before proceeding with the experiment.
(Note: if you seal the tip with the plunger in place, you will probably
not be able to remove the plunger unless you destroy the seal.
Why?)
When your sealed syringe is ready for use, insert the plunger to the
20 ml mark of the syringe along with a thin wire as shown in the
diagram above. The wire will allow air to escape from beneath the
plunger, equalizing the pressure in the syringe with the atmosphere.
Use the lower ring of the plunger as your indicator.
Hold the plunger in place and carefully withdraw the wire.
Make sure that the plunger can move freely in the syringe, and that
the tip of the syringe is well-sealed. Give the plunger a small
downward push, and verify that it springs back. If it does not, you
may need to lubricate the side of the plunger with a small amount of
silicone lubricant or you may not have sealed the tip of your syringe
properly.
When you are satisfied with the results of the previous step, record
the initial volume of air in the syringe and the ambient temperature.
You will be immersing the syringe into a water bath, and observing
the changes in volume of the gas as you change the temperature of
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
the water. Since the air in the syringe will make it buoyant, you need
a way to hold the syringe under the water. If you have a ringstand
and clamp, you're all set. Otherwise, you can put together a
homemade clamp with materials you'll probably have around the
house. Here's how:
a. Wrap a rubber band around the top of the syringe tube, just
below the finger flanges.
b. Insert the chopsticks (as noted in Materials & Equipment,
wood dowels can be substituted for chopsticks) through loops
of this rubber band, one on either side of the syringe. Slide the
syringe so that it is about 7–8 cm (3 in) in from the ends of the
chopsticks.
c. Wrap the second rubber band around the short ends of the
chopsticks. This will make a "V" shape, with the syringe held
tightly down near the point.
d. This second rubber band can also be used to hold the
thermometer upright in the water. Keep the bulb immersed in
the water, but not touching the side or bottom of the pot.
e. Place this assembly on the top of your cooking pot, so that the
chopsticks are supported by the rim of the pot and the syringe
sticks down into the pot.
f. To hold the syringe in place when the pot is filled with water,
place your weight (e.g., a can of soup) on top of the wide end
of the "V" made by the chopsticks.
g. Make any necessary adjustments to make the syringe and
thermometer stable, and make sure that you can read the
scale on the syringe.
Making the Measurements and Presenting Your Results
1.
2.
3.
4.
5.
6.
Remove the syringe and thermometer assembly from the pot and
set them aside.
Place the pot on the stove, but don't turn on the burner yet. Fill the
pot with ice cubes and enough water to immerse the syringe to
somewhere between the 30 and 35 ml marks.
Replace the syringe and thermometer assembly, and weight it down
securely.
Allow several minutes temperature in the water bath to stabilize and
for the temperature of the air in the syringe to equilibrate with the
water bath. Gentle stirring may help, but be careful not to break the
thermometer or knock your weight off your clamp.
Record the temperature of the water bath and the volume of the air
in the syringe. You may want to tap the plunger lightly to make sure
it is free to move. (If necessary, carefully (and briefly) lift the syringe
out of the water to read the volume. You may want to have an adult
help you with this part.)
Turn the burner on (no higher than medium heat) to gradually heat
the water. At regular intervals (e.g., every 10°C), turn the heat off
and allow the temperature to stabilize. Again, record the
temperature of the water bath and the volume of air in the syringe.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
7. Repeat the previous step up to 80 or 90°C. The pot will be quite full,
so it is best to avoid boiling the water.
8. As with any experiment, it is a good idea to repeat your
measurements to be sure that your results are consistent. We
suggest at least three separate trials. (Note that the temperatures
used do not need to be exactly the same from trial to trial!)
9. Make a graph of gas volume vs. temperature for all of your data
points. It's a good idea to use a different symbol for each of your
trials (if something was wrong with one particular trial, it may help
you understand what went wrong).
Questions
1. What is the relationship between volume and temperature in your
data set?
2. Can you extrapolate from your data to find the temperature that
corresponds to a gas volume of zero? How confident are you with
this result, and why?
3. Would your data look different if you used kelvins for the
temperature axis instead of degrees Celsius?
4. Was the assumption of constant pressure valid?
5. What are the possible sources of error in your experiment?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects
{Chemistry}~Measuring the Amount of Acid
in Vinegar by Titration with an Indicator
Solution
Objective
The goal of this project is to determine the amount of acid in different
types of vinegar using titration with a colored pH indicator to determine
the endpoint.
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 (Wikipedia contributors, 2007).
In this project, you will determine the amount of acid in different
vinegars usingtitration, 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. Let's go through the process with a
specific example: the titration of acetic acid. But before we go over
titration, here is a quick review of the chemistry of acids and bases.
It all has to do with hydrogen ions (abbreviated with the chemical
symbol H+). In water (H2O), a small number of the
molecules dissociate (split up). Some of the water molecules lose a
hydrogen and become hydroxyl ions (OH−). The "lost" hydrogen ions
join up with water molecules to form hydronium ions (H3O+). By
convention (and for simplicity in writing chemical equations),
hydronium ions are referred to as hydrogen ions H+. In pure water,
there are an equal number of hydrogen ions and hydroxyl ions. The
solution is neither acidic or basic.
An acid, like acetic acid, is a substance that donates hydrogen ions.
When acetic acid is dissolved in water, the balance between hydrogen
ions and hydroxyl ions is shifted. Now there are more hydrogen ions
than hydroxyl ions in the solution. This kind of solution is acidic.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
A base is a substance that accepts hydrogen ions. When a base is
dissolved in water, the balance between hydrogen ions and hydroxyl
ions shifts the opposite way. Because the base "soaks up" hydrogen
ions, the result is a solution with more hydroxyl ions than hydrogen
ions. This kind of solution is alkaline.
To measure the acidity of a vinegar solution, you 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, you 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, you'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 you add to the solution, you can expect to produce a
hydroxyl ion.
To dispense an accurately measured volume of the titrating solution,
you will use a buret. A buret is a long tube with a valve at the bottom
and graduated markings on the outside to measure the volume
contained in the buret. The buret is mounted on a ring stand, directly
above the titrant solution (as shown below).
The illustration shows a buret (filled with titration solution) mounted on a ring stand above a beaker
(containing the titrant solution) (G. Carboni, 2004).
Solutions in the buret 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
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
surface of the liquid thus forms a curve, called a meniscus. To
measure the volume of the liquid in the buret, always read from the
bottom of the meniscus. In the illustration below, I'd say that the fluid
level is 14.58 mL.
Always read the fluid level in the buret from the bottom of the meniscus (G. Carboni, 2004).
In this experiment, you will use an indicator solution called
pheonolphthalein. (I love to say that word: fee-nol-fthay-leen!)
Phenolphthalein is colorless 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 your vinegar solution starts to turn pink, you know that the
titration is complete.
Which type of vinegar do you think will have the most acetic acid? Find
out for yourself with this project.
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:









Vinegar
Acids and bases
o Acetic acid (CH3COOH)
o Sodium hydroxide (NaOH)
pH scale (see the Science Buddies Chemistry Resource, Acids,
Bases, and the pH Scale)
Indicator solutions (e.g., phenolphthalein)
Stoichiometry
Titration
Meniscus
Buret
Titrant
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Questions





What value of pH is neutral?
What range of pH values is acidic?
What range of pH values is basic?
How does a pH indicator work?
At what pH does phenolphthalein change from colorless to pinkish?
Bibliography






To get you started, here is a Wikipedia article on vinegar:
Wikipedia contributors, 2007. "Vinegar," Wikipedia, The Free
Encyclopedia [accessed July 24,
2006] http://en.wikipedia.org/w/index.php?title=Vinegar&oldid=1465
05883.
Here is a good introduction to acid-base chemistry:
o Carboni, G., 2004a. "Experiments with Acids and Bases," Fun
Science Gallery [accessed July 24,
2007]http://www.funsci.com/fun3_en/acids/acids.htm.
o This project is based on the vinegar titration experiment about
4/5 of the way down the page:
Carboni, G., 2004b. "Experiments with Acids and Bases: How
Acid Is That Vinegar?" Fun Science Gallery [accessed July 24,
2007]http://www.funsci.com/fun3_en/acids/acids.htm#11.
These webpages have a quick review of exponents and logarithms:
o U of MN, 2004a. "What Is an Exponent?" Math Review: Useful
Math for Everyone, University of Minnesota, School of Public
Health [accessed July 24,
2007] http://www.mclph.umn.edu/mathrefresh/exponents.html.
o U of MN, 2004b. "What Is a Logarithm?" Math Review: Useful
Math for Everyone, University of Minnesota, School of Public
Health [accessed July 24,
2007] http://www.mclph.umn.edu/mathrefresh/logs.html.
For more information about the pH scale, try these references:
o Environment Canada, 2002. "Kids' Corner pH Scale," The
Green Lane: Acid Rain, Environment Canada website
[accessed July 24,
2006] http://www.ec.gc.ca/acidrain/kids.html.
o Decelles, P., 2002. "The pH Scale," Virtually Biology Course,
Basic Chemistry Concepts, Johnson County Community
College [accessed July 24,
2006] http://staff.jccc.net/pdecell/chemistry/phscale.html.
For more information on titration techniques see Chemistry Lab
Techniques.
CBSE Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:

Vinegar, at least three different types
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Tip: it will be easier to see the indicator change color with
lighter-colored vinegars.
Distilled water
Small funnel (do not use for food after using it for chemistry)
The following items can be ordered from Science Kit & Boreal
Laboratories:
o Chemical safety goggles
o Lab apron
o Rubber (latex) gloves
o 0.5% Phenolphthalein solution in alcohol (pH indicator
solution)
o 0.1 M sodium hydroxide solution
 Sodium hydroxide is caustic, which means it will cause a
chemical burn on bare skin.
 You will have to order this chemical through your school.
 This solution is fairly dilute and relatively safe to use with
proper chemical safety precautions (chemical safety
goggles, lab coat or apron, and rubber gloves).
 Tip: since each molecule of sodium hydroxide (NaOH)
can produce one hydroxide ion (OH−), 0.1 N sodium
hydroxide is the same as 0.1 M.
o 125 mL Ehrlenmeyer flask
o 25 or 50 mL buret
o 10 mL graduated cylinder
o Ring stand
o Buret clamp
o



Experimental Procedure
Note: this project requires the use of a sodium hydroxide solution, which is caustic. You
will have to order this chemical through your school. Proper safety precautions should
be used when working with this solution, including:



Chemical safety goggles
Lab coat/apron
Gloves
Performing the Titration
1. Do your background research so that you are knowledgeable about
the terms, concepts, and questions, above.
2. Since you will be working with dilute sodium hydroxide, you should
take proper safety precautions:
a. Wear safety goggles for chemistry, an apron (or lab coat), and
a pair of rubber gloves.
b. If you spill sodium hydroxide on your skin, wash it off quickly
with lots of running water.
3. Pour 1.5 ml of vinegar in an Ehrlenmeyer flask.
a. These flasks are designed so that you can swirl the solution
inside without spilling it.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
4.
5.
6.
7.
8.
b. Tip: you can also use a regular beaker and a stirring rod to
keep the solution mixed as you titrate.
Dilute the vinegar with about 50 ml of distilled water.
Add 3 drops of 0.5% phenolphthalein solution.
a. Phenolphthalein solution is colorless at acidic pH, and turns
light purple at about pH 8.3.
b. The vinegar solution is acidic, so it should remain colorless.
Use the buret clamp to attach the buret to the ring stand. The
opening at the bottom of the buret should be just above the height of
the Ehrlenmeyer flask you use for the vinegar/water/phenolphthalein
solution.
Use a funnel to fill the buret with a 0.1 M solution of sodium
hydroxide.
Note the starting level of the sodium hydroxide solution in the buret.
Remember to read from the bottom of the meniscus. In the
illustration below, I'd say that the fluid level is 14.58 mL.
Always read the fluid level in the buret from the bottom of the meniscus. (G. Carboni, 2004)
9. Put the vinegar solution to be titrated under the buret. The
illustration below shows an example of the experimental setup at the
beginning of the titration.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
At the start of the vinegar titration, the phenolphthalein is colorless. (G. Carboni, 2004)
10.
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 buret. (Alternative is to use a beaker and
stirring rod—but be careful not to hit the buret with the stirring rod.)
11.
At some point you will see a pink color in the vinegar solution
when the sodium hydroxide is added, but the color will quickly
disappear as the solution is mixed. When this happens, slow the
buret to drop-by-drop addition.
12.
When the vinegar solution turns pink and remains that color
even with mixing, the titration is complete. Close the tap (or pinch
valve) of the buret. The illustration below shows how the solution
color changes at the endpoint of the titration.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
The endpoint of the titration is reached when the phenolphthalein in solution turns pinkish.
(G. Carboni, 2004)
13.
Note the remaining level of the sodium hydroxide solution in
the buret. Remember to read from the bottom of the meniscus.
14.
Subtract the initial level from the remaining level to figure out
how much titrating solution you have used.
15.
For each vinegar that you test, repeat the titration at least
three times. If you are careful with all of your volume
measurements, the results of your three repeated trials should
agree within 0.1 mL.
Analyzing Your Results
Here's how to figure out how much acetic acid was in each sample.
1. Determine the number of moles of sodium hydroxide used to titrate
the vinegar.
a. Multiply the volume of added sodium hydroxide (in liters) by
the concentration (in moles/liter).
b. For example, if you added 12.5 mL of sodium hydroxide, the
number of moles would be 0.0125 L × 0.1 moles/L = 0.00125
moles.
2. Determine the concentration of acetic acid in the vinegar.
a. The number of moles of sodium hydroxide equals the number
of moles of acetic acid in your vinegar sample (Ms).
b. The sample volume was 1.5 mL (Vs).
c. You can use a proportion to determine the number of moles of
acetic acid (Mx) in a standard volume (Vx = 1 L) of
vinegar: Ms/Vs = Mx/Vx.
d. Continuing with the previous example, the number of moles of
acetic acid would be 0.00125. Dividing by 0.0015 L gives
0.833 moles of acetic acid per liter, or a concentration of 0.833
M.
e. You can also calculate the concentration in terms of grams of
acetic acid per liter. To do this, multiply the molar
concentration of acetic acid by the molecular mass of acetic
acid, which is 60. In the case of our example, the
concentration would be 0.833 × 60 = 50 g/L, or 5.0%.
3. Repeat the calculations for each type of vinegar you tested. Which
vinegar had the highest concentration of acetic acid?
Variations




Measure the acidity of solutions such as beer or wine.
Measure the acidity of other beverages, such as: different fruit
juices, soda, sport drinks, coffee, or teas.
Measure the acidity of fermenting apple cider over time.
Measure the acidity of uncorked wine over time (check once a day
over the course of a week).
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects
{Chemistry}~Measuring Surface Tension of
Water with a Penny
Objective
The goal of this project is to investigate how added salt and added
detergent affect the surface tension of water.
Introduction
Water molecules—good old H2O—are made of one oxygen and two
hydrogen atoms. The single oxygen and two hydrogen atoms are held
together because they share electrons—this is called a covalent bond.
The hydrogen atoms don't line up on opposite sides of the oxygen
atom, as you might think. Instead they are at an angle of about 105° (if
they were on opposite sides of the oxygen atom the angle would, of
course, be 180°).
The oxygen atom tends to hold on to the shared electrons from the
hydrogen atoms more tightly, so each end of the water molecule ends
up with a partial charge. The oxygen portion of the molecule has a
partial negative charge, and the hydrogen ends of the molecule have a
partial positive charge. Another way of talking about the partial
charges is to say that water molecules are polarized. Like a magnet,
with a north and south pole, a water molecule has electrical poles. The
oxygen atom is the negative pole, and each hydrogen atom is a
positive pole.
These partial charges cause water molecules to interact with one
another. Because opposite charges attract, water molecules tend to
'stick' to one another. The partial positive charges of the hydrogen
atoms tend to align themselves with the partial negative charge of the
oxygen atoms of neighboring water molecules. You can see models of
this alignment in several of the references in the Bibliography section
(Wiseth, date unknown; Hipschman, 1995a; Kimball, 2006). This
tendency of water molecules to stick together due to the partial
positive and negative charges is called hydrogen bonding.
Hydrogen bonding between water molecules leads to many interesting
consequences at the visible, macroscopic level. For example: the
boiling point of water, its surface tension, and it's ability to dissolve
salts are all related to hydrogen bonding.
The boiling point of water, 100°C, is unusually high for a molecule with
such a low molecular weight. The boiling point is so high due to
hydrogen bonding. On average, each water molecule interacts with
about four others (each hydrogen atom interacts with the oxygen atom
of separate water molecules, and each oxygen atom interacts with the
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
hydrogen atoms of two more water molecules). In water vapor, the
molecules are too far apart for hydrogen bonding to occur, so boiling
water means breaking up all of the hydrogen bonds in liquid water.
Breaking those bonds takes energy, thus the high boiling point for
water.
Hydrogen bonds also give liquid water a high surface tension. The
water molecules on the surface have partners for hydrogen bonding
only within the liquid; above the water surface there are no more
molecules available for hydrogen bonding. This means that molecules
at the surface experience a net force pulling them inward. If you fill a
glass right up to the rim and then carefully add a few more drops of
water, you can see that the glass can be overfilled without spilling. The
surface tension of the water holds on to the 'extra' water as if there
were a skin on the surface of the water.
Water is an excellent solvent for charged (polar) molecules like table
salt, NaCl. In water, salt dissociates into positively charged sodium
(Na+) and negatively charged chloride (Cl−) ions. The partial positive
charge of the hydrogen ends of the water molecules surround the
negatively charged chloride ions, and the partial negative charge of the
oxygen ends of the water molecules surround the positively charged
sodium ions. What effect will dissolved salt ions have on hydrogen
bonds between water molecules?
Water behaves very differently when mixed with uncharged (nonpolar)
molecules. An example of a nonpolar molecule is cooking oil. You may
have heard the saying "oil and water don't mix," and this is why. Oil
molecules are uncharged. Water molecules, as you have learned, are
partially charged. The uncharged oil molecules disrupt the hydrogen
bonding between water molecules. So when you try to mix oil and
water, the oil ends up forming droplets within the water. The nonpolar
oil molecules stick together and the polar water molecules stick
together. Eventually, you get two layers, with the less dense oil floating
on top of the denser water.
Nonpolar substances are sometimes called 'hydrophobic' (meaning
'water fearing'), and polar molecules are sometimes called 'hydrophilic'
(meaning 'water loving') because of the two different interactions
illustrated by salt and cooking oil.
Liquid detergents have dual properties. One end of the molecule is
oily, and the other end is charged. In water, the oily ends of detergent
molecules stick together, with the charged ends sticking out, into the
water. Detergents can form small blobs in water (called micelles) and
can also disperse, like oils, into a layer on the surface of the water (for
illustrations, see Hipschman, 1995b). How do you think added
detergent will affect the surface tension of water?
One way to find out is to count how many drops of water you can 'pile
up' on top of a single penny. The Experimental Procedure section
shows you how to do this with plain water, salt water, and water with
detergent.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:








surface tension,
chemical structure of water,
covalent bond,
hydrogen bonds,
polar solvent,
non-polar solvent,
hydrophobic,
hydrophilic.
Questions




What happens to salt when it is dissolved in water?
How do you think adding salt to the water will affect the hydrogen
bonds between water molecules?
o What effect will this have on surface tension?
o Do you think salt water will have more or less surface tension
than plain tap water?
What happens to detergent when it is dissolved in water?
How will added detergent affect hydrogen bonds between water
molecules?
o What effect will this have on surface tension?
o Do you think water with added detergent will have more or less
surface tension than plain tap water?
Bibliography



This animation shows how hydrogen bonding occurs between water
molecules (requires Shockwave plug-in):
Wiseth, T., date unknown. "A Closer Look at Water," Northland
Community and Technical College [accessed February 14,
2007]http://www.northland.cc.mn.us/biology/Biology1111/animations
/hydrogenbonds.html.
These webpages about bubbles from San Francisco's Exploratorium
explain how hydrogen bonds make water a "sticky" fluid, and how
soap disrupts this "stickiness."
o Hipschman, R., 1995a. "Sticky Water," Exploratorium
[accessed February 14,
2007]http://exploratorium.edu/ronh/bubbles/sticky_water.html.
o Hipschman, R., 1995b. "Soap," Exploratorium [accessed
February 14,
2007] http://exploratorium.edu/ronh/bubbles/soap.html.
Here is another brief description of hydrogen bonding in water:
Kimball, J.W., 2006. "Hydrogen Bonds," Kimball's Biology Pages
[accessed February 14,
2007]http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hydr
ogenBonds.html.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com



Wikipedia contributors, 2007. "Surface Tension," Wikipedia, The
Free Encyclopedia [accessed February 14,
2007]http://en.wikipedia.org/wiki/Surface_tension.
Tureki, R., 2006. "The General Chemistry Demo Lab: Surface
Tension," [accessed February 14,
2007]http://www.ilpi.com/genchem/demo/tension/index.html.
CBSE Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:






water,
plastic transfer pipettes (or eyedropper),
o one online source of transfer pipettes in small quantities is
RachelsSupply.com, where you can get 10 fine-tipped pipettes
(part #1N01) for $1.50 + shipping.
salt,
dishwashing detergent,
clean glass jars (or beakers),
measuring spoons.
Experimental Procedure
1. Holding the transfer pipette close to the surface of the penny,
carefully pipet water droplets onto the penny, one at a time,
counting each drop. Tips:
a. The droplets should pool up on the penny, creating a big
droplet of water.
b. To make sure your count is accurate, hold the pipette far
enough above the penny so that the drop has to fall a short
distance before fusing with the droplet on the penny.
2. Stop pipetting when the droplet on the penny breaks up and
overflows. The count for each trial is the number of drops that the
penny could hold (in other words, count all of the drops except the
one that caused the penny to overflow).
3. Repeat the measurement ten times for each solution that you test.
4. Test the following solutions:
a. added salt: dissolve 1 teaspoon (6 grams) in 100 mL of water,
b. added detergent: put 1 drop of liquid dishwashing detergent in
1 liter of water; do not shake–cap the container and gently tip it
back and forth to mix.
Variations

Try a series of increasing concentrations of salt (maximum solubility
at room temperature is about 36 g salt/100 mL water). The best way
to do this is by making a concentrated solution, and then making
serial dilutions to make less-concentrated solutions. Does surface
tension continue to change as more salt is added? Students who
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


have studied high school chemistry should compare molar ratios of
NaCl and H2O.
Do you think that changing the temperature of the water would
affect surface tension? How? Design an experiment to find out.
Measuring surface tension on a penny is probably not the best
design for this variation, because the temperature would not be well
controlled. The volume of water is quite small, so the temperature
could easily change. However, if you controlled the temperature of
the water and the penny, you could probably get this to work.
Another idea would be to find a different way to measure surface
tension, using a larger volume of water.
Does the surface of the penny matter? What happens if you coat the
penny with a thin film of cooking oil? Wet a paper towel slightly with
cooking oil. Wipe off the excess oil, then use the paper towel to wipe
a thin film of oil on a penny. How many drops of water will the penny
hold compared to a "normal" penny. Can you think of other surface
treatments you could try? Could you make penny-sized disks of
other materials to test? How important is the raised edge of the
penny for holding the water? Does the 'heads' side hold more or
less water than the 'tails' side?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects {Chemistry}~What
Makes Ice Melt Fastest?
Objective
The goal of this project is to determine which added material will make
ice melt fastest.
Introduction
To make ice cream with an old-fashioned hand-crank machine, you
need ice and rock salt to make the cream mixture cold enough to
freeze. If you live in a cold climate, you've seen the trucks that salt and
sand the streets after a snowfall to prevent ice from building up on the
roads. In both of these instances, salt is acting to lower the freezing
point of water.
For the ice cream maker, because the rock salt lowers the freezing
point of the ice, the temperature of the ice/rock salt mixture can go
below the normal freezing point of water. This makes it possible to
freeze the ice cream mixture in the inner container of the ice cream
machine. For the salt spread on streets in wintertime, the lowered
freezing point means that snow and ice can melt even when the
weather is below the normal freezing point of water. Both the ice
cream maker and road salt are examples of freezing point depression.
Salt water is an example of a chemical solution. In a solution, there is
a solvent (the water in this example), and a solute (the salt in this
example). A molecule of the solute will dissolve (go into solution) when
the force of attraction between solute molecule and the solvent
molecules is greater than the force of attraction between the molecules
of the solute. Water (H2O) is a good solvent because it is partially
polarized. The hydrogen ends of the water molecule have a partial
positive charge, and the oxygen end of the molecule has a partial
negative charge. This is because the oxygen atom holds on more
tightly to the electrons it shares with the hydrogen atoms. The partial
charges make it possible for water molecules to arrange themselves
around charged atoms (ions) in solution, like the sodium (Na+) and
chloride (Cl−) ions that dissociate when table salt dissolves in water.
Other substances that dissolve in water also lower the freezing point of
the solution. The amount by which the freezing point is lowered
depends only on the number of molecules dissolved, not on their
chemical nature. This is an example of a colligative property. In this
project, you'll investigate different substances to see how they affect
the rate at which ice cubes melt. You'll test substances that dissolve in
water (i.e., soluble substances), like salt and sugar, as well as
substances that don't dissolve in water (i.e., insoluble substances), like
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
sand and pepper. Which substances will speed up the melting of the
ice?
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:







Solution
Solute
Solvent
Colligative properties
Freezing point depression
Phases of matter
o Solid
o Liquid
o Gas
o Plasma
Phase transitions
o Melting
o Freezing
o Evaporation
o Condensation
o Sublimation
Questions


Which of the suggested test substances are soluble in water?
Which of the suggested test substances are insoluble in water?
Bibliography



For more information on colligative properties, see:
o Eli, Todd & Keith, date unknown. "Colligative Properties,"
Chemworld, ThinkQuest Library, Oracle Education Foundation
[accessed September 6,
2007]http://library.thinkquest.org/C006669/data/Chem/colligati
ve/colligative.html?tqskip1=1.
o Nave, C.R., 2006. "Colligative Properties of Solutions,"
HyperPhysics, Department of Physics and Astronomy,
Georgia State University [accessed September 6,
2007] http://hyperphysics.phyastr.gsu.edu/hbase/chemical/collig.html.
For information on Avogadro's number and molecular weight, see:
o Lachish, U., 2000. "Avogadro's Number, Atomic and Molecular
Weight," [accessed September 6,
2007]http://urila.tripod.com/mole.htm.
o Furtsch, T.A., date unknown. "Avogadro's Number,"
Tennessee Technological University [accessed September 6,
2007]http://gemini.tntech.edu/~tfurtsch/scihist/avogadro.htm.
To try a simulated experiment on freezing point depression or
boiling point elevation, see (Flash animation, requires browser plugPRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com

in):
Greenbowe, T.J., 2005. "Boiling-Point Elevation and Freezing-Point
Depression," Department of Chemistry, Iowa State University
[accessed September 6,
2007]http://www.chem.iastate.edu/group/Greenbowe/sections/proje
ctfolder/flashfiles/propOfSoln/colligative.html.
Cbse Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:






Ice cubes
Identical plates or saucers
Timer
Electronic kitchen balance (accurate to 0.1 g)
Measuring cup
Suggested materials to test for ice-melting ability
o Table salt
o Sugar
o Sand
o Pepper
Experimental Procedure
1. Do your background research so that you are knowledgeable about
the terms, concepts, and questions, above.
2. You'll need a clean plate and several ice cubes for each of the
substances to be tested.
3. Note the starting time, then carefully sprinkle one teaspoon of the
substance to be tested over the ice cube.
4. After a fixed amount of time (say, 10 minutes), pour off the melted
water into a measuring cup, and use the balance to measure the
mass. Subtract the mass of the empty cup, and you'll have the mass
of the melted water. Wait the same amount of time for each test.
5. Measure the remaining mass of the ice cube.
6. Repeat three times for each substance to be tested.
7. Use the same procedure to measure the melting rate for ice cubes
with nothing added.
8. For each test, calculate the percentage of the ice cube that melted:
[mass of melt water]/[initial mass of ice cube] × 100
9. For each test, calculate the percentage of the ice cube remaining:
[remaining mass of ice cube]/[initial mass of ice cube] × 100
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
10.
For each substance you tested, calculate the average amount
of melted water produced (as a percentage of initial mass), and the
average remaining ice cube mass (as a percentage of initial mass).
11.
Did any substances speed up melting of the ice (compared to
melting rate of plain ice cubes with nothing added)?
Variations



Does the melting rate depend on the amount of solute added?
Design an experiment to find out.
Try your experiment in the refrigerator to simulate colder weather.
Alternatively, if the outside temperature is wintry, take your
experiment outdoors! Be sure to monitor the temperature regularly
throughout your experiment.
Do you think salt would melt ice in your freezer? Why or why not?
Try it and find out.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects {Chemistry}~Make
Your Own pH Paper
Objective
The goal of this project is to make your own pH indicator paper, and
use it to measure the acidity and alkanity of various solutions from
around your house.
Introduction
In this project you'll learn how to make your own pH paper that you can
use to find out if a solution is acidic or basic (alkaline). What does it
mean for a solution to be acidic or alkaline?
It all has to do with hydrogen ions (abbreviated with the chemical
symbol H+). In water (H2O), a small number of the molecules
dissociate (split up). Some of the water molecules lose a hydrogen and
become hydroxyl ions (OH−). The "lost" hydrogen ions join up with
water molecules to form hydronium ions (H3O+). For simplicity,
hydronium ions are referred to as hydrogen ions H+. In pure water,
there are an equal number of hydrogen ions and hydroxyl ions. The
solution is neither acidic or basic.
An acid is a substance that donates hydrogen ions. Because of this,
when an acid is dissolved in water, the balance between hydrogen
ions and hydroxyl ions is shifted. Now there are more hydrogen ions
than hydroxyl ions in the solution. This kind of solution is acidic.
A base is a substance that accepts hydrogen ions. When a base is
dissolved in water, the balance between hydrogen ions and hydroxyl
ions shifts the opposite way. Because the base "soaks up" hydrogen
ions, the result is a solution with more hydroxyl ions than hydrogen
ions. This kind of solution is alkaline.
Acidity and alkalinity are measured with a logarithmic scale called pH.
Here's why: A strongly acidic solution can have one hundred million
million (100,000,000,000,000) times more hydrogen ions than a
strongly basic solution! The flip side, of course, is that a strongly basic
solution can have 100,000,000,000,000 times more hydroxide ions
than a strongly acidic solution. Moreover, the hydrogen ion and
hydroxide ion concentrations in everyday solutions can vary over that
entire range. In order to deal with these large numbers more easily,
scientists use a logarithmic scale, the pH scale. Each one-unit change
in the pH scale corresponds to a ten-fold change in hydrogen ion
concentration. The pH scale ranges from 0 to 14. It's a lot easier to use
a logarithmic scale instead of always having to write down all those
zeros! By the way, notice how one hundred million million is a one with
fourteen zeros after it? It's not coincidence, it's logarithms!
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
To be more precise, pH is the negative logarithm of the hydrogen ion
concentration:
pH = log 1/[H]+ = −log [H+] .
The square brackets around the H+ automatically mean "concentration" to
a chemist. What the equation means is just what we said before: for each
1-unit change in pH, the hydrogen ion concentration changes ten-fold.
Pure water has a neutral pH of 7. pH values lower than 7 are acidic, and
pH values higher than 7 are alkaline (basic). The table below has
examples of substances with different pH values (Decelles, 2002;
Environment Canada, 2002; EPA, date unknown).
Table 1. The pH Scale: Some Examples
pH Value
H+ Concentration
Example
Relative to Pure Water
0 10 000 000
battery acid
1 1 000 000
sulfuric acid
2 100 000
lemon juice, vinegar
3 10 000
orange juice, soda
4 1 000
tomato juice, acid rain
5 100
black coffee, bananas
6 10
urine, milk
7 1
pure water
8 0.1
sea water, eggs
9 0.01
baking soda
10 0.001
Great Salt Lake, milk of magnesia
11 0.000 1
ammonia solution
12 0.000 01
soapy water
13 0.000 001
bleach, oven cleaner
14 0.000 000 1
liquid drain cleaner
In this project you will make your own pH paper from a colored
indicator that you will extract from red cabbage by cooking it in water.
Once you have the indicator solution, you can soak some coffee filter
paper in it, then allow the paper to dry. When the paper is dry, you can
cut it into strips, and you'll have pH paper that will change color. It will
turn greenish when exposed to bases, and reddish when exposed to
acids. How green or how red? That's your job! Use different solutions
that you have around the house to find out how the color change
corresponds to changes in pH.
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:

Acids
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com




Bases
Logarithms
pH
pH indicators
Questions





What value of pH is neutral?
What range of pH values is acidic?
What range of pH values is basic?
What color is red cabbage pH paper when dipped in acidic
solutions?
What color is red cabbage pH paper when dipped in basic
solutions?
Bibliography





Here is two good websites about acids and bases, including
information about indicators:
o Carboni, G., 2004. "Experiments with Acids and Bases," Fun
Science Gallery [accessed July 12,
2007]http://www.funsci.com/fun3_en/acids/acids.htm.
o Bogren, S. et al., n.d. "Acids, Bases and pH Scale," Urbana
Middle School Teachers, Urbana, IL [accessed July 12,
2007]http://lrs.ed.uiuc.edu/students/erlinger/water/background/
ph.html.
This webpage has instructions for making several different colored
pH indicators, including beet juice, phenolphthalein (from laxative
tablets), red cabbage, and turmeric:
Beckham, R., date unknown. "pH Indicators and Tests for Acids and
Bases," Learn NC, School of Education, University of North
Carolina, Chapel Hill [accessed July 12,
2007]http://www.learnnc.org/lessons/RichardBeckham5232002901.
This webpage has a video on making turmeric pH paper:
Krampf, R., 2006. "Science Experiment #16: Making Turmeric
Paper," Robert Krampf Science Education Co. [accessed July 12,
2007]http://www.krampf.com/experiments/Science_Experiment16.ht
ml.
These webpages have a quick review of exponents and logarithms:
o U of MN, 2004a. "What Is an Exponent?" Math Review: Useful
Math for Everyone, University of Minnesota, School of Public
Health [accessed July 12,
2007] http://www.mclph.umn.edu/mathrefresh/exponents.html.
o U of MN, 2004b. "What Is a Logarithm?" Math Review: Useful
Math for Everyone, University of Minnesota, School of Public
Health [accessed July 12,
2007] http://www.mclph.umn.edu/mathrefresh/logs.html.
For more information about the pH scale, try these references:
o Environment Canada, 2002. "Kids' Corner pH Scale," The
Green Lane: Acid Rain, Environment Canada website
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
o
o
[accessed July 12,
2006] http://www.ec.gc.ca/acidrain/kids.html.
Decelles, P., 2002. "The pH Scale," Virtually Biology Course,
Basic Chemistry Concepts, Johnson County Community
College [accessed July 12,
2006] http://staff.jccc.net/pdecell/chemistry/phscale.html.
Cbse Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:







Red cabbage leaves
1-quart cooking pot
Water
1-quart bowl
Strainer
White coffee filters (cone-shaped ones are good)
o Alternatively, you can use filter paper or chromatography
paper.
Acidic and basic solutions to test, for example:
o Lemon juice, vinegar
o Orange juice, soda
o Tomato juice, acid rain
o Black coffee, bananas
o Milk, saliva
o Pure water
o Sea water, eggs
o Baking soda solution
o Milk of magnesia
o Ammonia solution
o Soapy water
Experimental Procedure
Safety Notes:



Adult supervision required.
Do not mix strong acids and bases.
Use appropriate caution when testing the pH of household cleaning solutions (like ammonia).
Avoid skin contact, and follow all precautions on the product label.
1. Do your background research so that you are knowledgeable about
the terms, concepts, and questions, above.
2. Prepare a red cabbage indicator solution (the "Experiments with
Acids and Bases" webpage (Carboni, 2004) has great pictures
illustrating all of the steps)
a. Slice a head of cabbage at approximately 3 cm (1 in) intervals,
or peel the leaves from the head and tear them into pieces.
b. Place the leaves in the cooking pot and cover with water.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
3.
4.
5.
6.
c. Cook on medium heat for half an hour (low boil is good).
d. Allow the cooked cabbage to cool, then pour off the liquid into
a bowl. You can pour through a strainer to catch the cabbage
pieces, or hold them back with a large, flat ladle with holes—
see the photographs on the "Experiments with Acids and
Bases" webpage (Carboni, 2004).
e. The solution is a deep blue, but will change color when the pH
changes. (You can experiment with using the liquid as a pH
indicator.)
Here's how to make pH paper using the red cabbage solution and
coffee filters:
a. Soak the white coffee filters in the red cabbage solution for
about 30 minutes.
b. Drain the excess solution from the filters, and set them out in a
single layer on some paper towels to dry overnight. To speed
up the drying process, you can put them on a cookie sheet
and put them in your oven at low temperature (150–200°F.
c. When the coffee filters are dry, cut them into 3 cm × 8 cm
(about 1 in × 3 in) strips.
d. The strips are now ready to test the pH of various solutions.
They start out blue, but will turn green in basic solutions and
red in acidic solutions.
Use the strips to test the acidity/alkalinity of various solutions around
your house. For example:
a. Lemon juice, vinegar
b. Orange juice, soda
c. Tomato juice, acid rain
d. Black coffee, bananas
e. Milk, saliva
f. Pure water
g. Sea water, eggs
h. Baking soda solution
i. Milk of magnesia
j. Ammonia solution
k. Soapy water
l. Note: if you test the pH of saliva, do not put the pH paper in
your mouth! Instead, spit some saliva into a clean container
and dip the paper into the saliva.
After testing, put the pH strips in order of increasing pH of the
solution tested.
a. You can use the table in the Introduction as a guide.
b. The Variations section has some additional suggestions for
independent confirmations of the pH readings.
Do you see a gradual change in color as the pH of the tested
solutions varies? Can you match specific colors to certain pH
levels? Over what range of pH does the color continue to change?
How accurately do you think you can determine the pH of a solution
with your test papers? Within 1, 2, or 3 pH units?
Variations
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com




Compare the performance of your homemade pH paper with
commercial pH paper (can be found in a well-stocked tropical fish
store). Or, buy an inexpensive pH meter and use it to calibrate your
homemade pH paper. Use the table in the Introduction to make a
series of different solutions, form low to high pH. Measure the pH of
each solution with the pH meter (rinse off the tip between solutions),
and write down the results. Now check each solution with your pH
paper. Can you see color differences that correspond to the
measured changes in pH? Over what pH range do you see color
changes? How large does the shift in pH need to be in order to see
a change in color?
Try making pH indicator solutions (and/or indicator papers) from
other natural dyes: for example beet juice, phenolphthalein, or
turmeric powder (Beckham, date unknown; Krampf, 2006). Test
your household solutions with each of the indicators. Does the
additional information from multiple indicators give you a better
measure of the pH of your solutions?
Does the pH of your saliva change after eating various types of
food? If so, how much time does it take to return to normal? Design
an experiment to find out. Again, do not put the pH paper in your
mouth. Instead, spit some saliva into a clean container and dip the
pH paper into the saliva. Also, don't try changing the pH of your
saliva with anything non-edible!
What is the pH of rainwater in your area? Can you measure it with
your pH paper or pH indicator solutions?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM- Science Projects {Chemistry}~What's
the Point of Boiling?
Objective
The goal of this project is to separate pure water from fruit juice using
a simple stovetop distillation apparatus.
Introduction
This project uses the technique of distillation. Distillation is when you
boil a liquid, and then capture the vapor that escapes from the liquid
and cool it. The cooled vapor condenses back into liquid. The
condensed liquid is called thedistillate. Do you think this process
changes the liquid?
What if the liquid you boil has substances dissolved in it? For example,
what if you started with a solution of sugar water? If you boiled the
sugar water, you know from experience that there would be steam
rising up from the pot on the stove. If you condensed that steam back
into liquid, do you think the condensed liquid (the distillate) would
contain sugar or not?
In this project, you will learn how to build a simple stove top distillation
apparatus with stuff that you probably have in your kitchen right now.
All you need is a deep pot with a sloping lid, a coffee cup, a bowl,
some ice, and a stove. Of course, you'll also need a liquid to distill.
Colored fruit juice will work fine, or you could make a solution of sugar
water. Add food coloring to it if you like. The Experimental Procedure
section, below, shows you how to put it all together to find out what
happens.
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:






Boiling point
Phases of matter:
o Solid
o Liquid
o Vapor
Condensation
Solvent
Solute
Distillate
Questions
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


What happens to solute molecules when the solvent evaporates or
boils?
How will the distillate compare to the original juice for:
o color?
o taste?
o pH?
Bibliography




For information on phase changes of water, see:
Nave, C.R. 2005. "Phase Changes," HyperPhysics, Department of
Physics and Astronomy, Georgia State University [accessed April
26, 2007]http://hyperphysics.phyastr.gsu.edu/hbase/thermo/phase.html.
Chamot, E. and B. Chamot, 2003. "Molecular Level Motion of
Different Phases," Chamot Laboratories, Inc. [accessed April 26,
2007]http://www.chamotlabs.com/Phases.html.
For information on the water cycle, see: USGS, 2006. "The Water
Cycle," USGS Water Science Basics [accessed April 26,
2007]http://ga.water.usgs.gov/edu/watercycle.html.
Cbse Blog : http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:







Stove
Deep cooking pot with sloped lid
Ceramic coffee cup
Ceramic bowl
Ice
Hot mitts
Colored fruit juice (e.g., orange juice, grape juice, cranberry juice,
etc.)
Experimental Procedure
1. Do your background research so that you are familiar with the
terms, concepts, and questions, above. For more information on
distillation methods.
2. The line drawing below is an illustration of the stove-top distillation
apparatus used in this experiment.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Line drawing of a stove top distillation apparatus. The text explains how to use it.
3. Here are the steps for using the distillation apparatus.
a. Pour the colored fruit juice into the bottom of the pot. Save at
least 200 ml of the original juice for comparison to the
distillate.
b. Place the ceramic coffee cup, open side up, in the center of
the deep pot. (That's correct, right in the juice!)
c. Place a bowl on top of the coffee cup. (The bowl will catch the
condensed liquid that drips down from the lid.)
d. Put the cover on the pot, upside down.
e. Put ice in the cover of the pot.
f. Turn on the burner to medium heat. You want the juice to boil
moderately (not a rolling boil).
g. Allow the pot to boil for 10 minutes or so (enough time to
collect a sufficient amount of distillate for testing).
h. When done, turn off the burner. Allow the pot to cool for a few
minutes.
i. Put on hot mitts and carefully remove the cover from the pot.
j. Still wearing hot mitts, lift the bowl off of the coffee cup and set
it down on a heat-resistant surface.
k. Remove the coffee cup.
l. After it cools, pour the remaining juice from the pot into a clear
container.
4. How do the original juice, the remaining juice from the pot, and the
distillate compare in terms of color?
5. Ordinarily in a chemistry experiment, you would not taste any of the
solutions. In this case, since you are using clean kitchen utensils,
and edible fruit juice, a taste test is OK. Let the liquids cool to room
temperature before tasting them! How do the three different liquids
compare for taste?
a. Which liquid is sweetest?
b. Which is least sweet?
c. You should be able to explain why.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects {Chemistry}~Big
Pieces or Small Pieces: Which React Faster?
Objective
The goal of this project is to measure the effect of reactant particle size
on the rate of a chemical reaction.
Introduction
You may have seen a television commercial for Alka-Seltzer tablets, or
heard one of their advertising slogans: "Plop, plop, fizz, fizz, oh what a
relief it is!®" When you drop the tablets in water, they make a lot of
bubbles, like an extra-fizzy soda. And like a soda, the bubbles are
carbon dioxide gas (CO2). However, with Alka-Seltzer®, the CO2 is
produced by a chemical reaction that occurs when the tablets dissolve
in water.
The main ingredients of Alka-Seltzer tablets are aspirin, citric acid, and
sodium bicarbonate (NaHCO3). When sodium bicarbonate dissolves in
water, it dissociates (splits apart) into sodium (Na+) and bicarbonate
(HCO3−) ions. The bicarbonate reacts with hydrogen ions (H+) from the
citric acid to form carbon dioxide and water. The reaction is described
by the following chemical equation:
So how does particle size come into this? In order for the reaction
shown above to take place, the ingredients in the tablet first have to
dissolve. The table has a large surface area, so this step should be
pretty fast, right? What effect do youthink particle size will have on the
speed of the bicarbonate reaction? You can find out for yourself by
plopping prepared Alka-Seltzer® tablets (whole tablets, halved tablets,
quartered tablets, and powdered tablets) into water at the same
temperature, and timing how long it takes for the chemical reaction to
go to completion.
Terms, Concepts and Questions to Start Background Research
To do this project, you should do research that enables you to
understand the following terms and concepts:





Molecules
Temperature
Reactants
Products
Reaction rate
Questions
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


Do you think changing the particle size will have a measurable
effect on the chemical reaction rate?
Will smaller particles speed up or slow down the reaction?
Bibliography



Bayer HealthCare, 2005. "Temperature and Rate of Reaction,"
Bayer HealthCare, LLC [accessed May 8, 2007] http://www.alkaseltzer.com/as/experiment/student_experiment1.htm.
Swanson, G.C., date unknown. "Chemistry Experiments for the
Home: Bubble Rate," Science Department, Daytona Beach
Community College [accessed May 8,
2007] http://faculty.dbcc.edu/swansoj/Bubble_Rate.htm.
Cbse Blog: http://cbse-sample-papers.blogspot.com
Materials and Equipment
To do this experiment you will need the following materials and
equipment:














At least 12 Alka-Seltzer® tablets (if you plan to do additional
variations to the project, you'll want to get a larger box)
Sheet of blank paper
Hammer
Piece of scrap wood
Thermometer (good range would be -10°C to 110°C
o E.g. catalog # WW6332000 from Science Kit & Boreal Lab or
catalog #15V1460 from Wards Natural Science)
o Standard kitchen candy thermometer will also work fine
Clear 12 ounce (355 mL) drinking glass (or larger)
o Note: Use Pyrex glass when working with water heated on the
stove or in the microwave)
Measuring cup
Masking tape
Something to stir with (a teaspoon or a chopstick, for example)
Tap water
Stop watch (you can also use a clock or watch with a second hand)
A helper
Lab notebook
Pencil
Experimental Procedure
1. Do your background research and make sure that you are familiar
with the terms, concepts, and questions, above.
2. In this experiment, you will be measuring the time it takes for one
Alka-Seltzer® tablet to react completely in water. You will
investigate how the reaction time changes as you vary the particle
size of the reactants.
3. You'll use the same glass for repeated trials, so it is convenient to
mark the desired water level.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
a. Use the measuring cup to add 8 ounces (236 mL) of water to
the glass. (If you're using metric volume units, rounding up to
250 mL is fine.)
b. Use a piece of masking tape on the outside of the glass to
mark the water level. Place the tape with its top edge even
with the water level in the glass.
c. Now you can use the masking tape to fill the glass to the right
level for each trial.
4. For observing the reaction, you will use the same volume of water at
the same starting temperature. The only variable that you should
change is the particle size of the tablets. You will use four different
particle sizes for the Alka-Seltzer® tablets:
a. A whole tablet
b. A tablet broken in half
c. A tablet broken in quarters
d. A tablet ground into powder. To do this, fold a single tablet to
be ground inside a clean piece of paper. Place the folded
paper on a piece of scrap wood, and use the hammer to firmly
pound the tablet about ten times. Stop immediately if the paper
shows signs of tearing: you don't want to lose any of the
powder.
5. Here is how to measure the reaction time:
a. Fill the glass with water to the level of the masking tape.
b. Measure the temperature of the water, and record it in your lab
notebook. Each trial should be carried out at the same
temperature, so adjust the water temperature (by adding warm
or cold water) as necessary.
c. Remove the thermometer. (It's not a good idea to use the
thermometer as a stirring rod. It might break.)
d. Have your helper get ready with the stop watch, while you get
ready with an Alka-Seltzer®. Have your helper count one–
two–three. On three, the helper starts the stop watch and you
drop the tablet (or tablet pieces) into the water.
e. You'll immediately see bubbles of CO2 streaming out from the
tablet.
f. Stir the water gently and steadily. Use the same stirring
method and speed for all of your experimental trials. The tablet
will gradually disintegrate. Watch for all of the solid white
material from the tablet to disappear.
g. When the solid material has completely disappeared and the
bubbles have stopped forming, say "Stop!" to have your helper
stop the stopwatch.
h. Record the reaction time in your lab notebook.
i. Tip: be careful when opening the packets and handling the
Alka-Seltzer® tablets. The tablets are thin and brittle, so they
break easily. You need to have four whole tablets for this
experiment.
6. For each of the four particle sizes, you should repeat the experiment
three times, for a total of 12 trials. You can organize your data in a
table like the one below.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
Particle Size
Temperature
(°C)
Reaction Time
(s)
Trial
#1
Trial
#2
Trial
#3
Average Reaction
Time
(s)
Whole Tablet
Tablet Broken in Half
Tablet Broken in
Quarters
Powdered Tablet
7. Calculate the average reaction time for each of the four particle
sizes.
8. Make a bar graph showing the average reaction time, in seconds,
(y-axis) vs. particle size (x-axis).
9. How does reaction time change with particle size?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-Science Projects {Chemistry}~Paper
Chromatography: Basic Version
Objective
The objective of this project is to use paper chromatography to analyze
ink components in permanent black markers.
Introduction
Matter makes up everything in the universe. Our body, the stars,
computers, and coffee mugs are all made of matter. There are three
different types of matter: solid, liquid, and gas. A solid is something
that is normally hard (your bones, the floor under your feet, etc.), but it
can also be powdery, like sugar or flour. Solids are substances that
are rigid and have definite shapes. Liquids flow and assume the shape
of their container; they are also difficult to compress (a powder can
take the same shape as its container, but it is a collection of solids that
are very small). Examples of liquids are milk, orange juice, water, and
vegetable oil. Gases are around you all the time, but you may not be
able to see them. The air we breathe is made up of a mixture of gases.
The steam from boiling water is water's gaseous form. Gases can
occupy all the parts of a container (they expand to fill their containers),
and they are easily compressed.
Matter is often a mixture of different substances. A heterogeneous
mixture is when the mixture is made up of parts that are dissimilar
(sand is a heterogeneous mixture). Homogeneous mixtures (also
called solutions) are uniform in structure (milk is a homogeneous
mixture). A sugar cube floating in water is a heterogeneous mixture,
whereas sugar dissolved in water is a homogeneous mixture. You will
determine whether the ink contained in a marker is a heterogeneous or
homogeneous mixture, or just one compound.
In a mixture, the substance dissolved in another substance is called
the solute. The substance doing the dissolving is called the solvent. If
you dissolve sugar in water, the sugar is the solute and the water is
the solvent.
For this project, you will be making a small spot with an ink marker
onto a strip of paper. The bottom of this strip will then be placed in a
dish of water, and the water will soak up into the paper.
The water (solvent) is the mobile phase of the chromatography
system, whereas the paper is the stationary phase. These two phases
are the basic principles of chromatography. Chromatography works by
something called capillary action. The attraction of the water to the
paper (adhesion force) is larger than the attraction of the water to itself
(cohesion force), hence the water moves up the paper. The ink will
also be attracted to the paper, to itself, and to the water differently, and
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
thus a different component will move a different distance depending
upon the strength of attraction to each of these objects. As an analogy,
let's pretend you are at a family reunion. You enjoy giving people hugs
and talking with your relatives, but your cousin does not. As you make
your way to the door to leave, you give a hug to every one of your
relatives, and your cousin just says "bye." So, your cousin will make it
to the door more quickly than you will. You are more attracted to your
relatives, just as some chemical samples may be more attracted to the
paper than the solvent, and thus will not move up the solid phase as
quickly. Your cousin is more attracted to the idea of leaving, which is
like the solvent (the mobile phase).
Chromatography is used in many different industries and labs. The
police and other investigators use chromatography to identify clues at
a crime scene like blood, ink, or drugs. More accurate chromatography
in combination with expensive equipment is used to make sure a food
company's processes are working correctly and they are creating the
right product. This type of chromatography works the same way as
regular chromatography, but a scanner system in conjunction with a
computer can be used to identify the different chemicals and their
amounts. Chemists use chromatography in labs to track the progress
of a reaction. By looking at the sample spots on the chromatography
plate, they can easily find out when the products start to form and
when the reactants have been used up (i.e., when the reaction is
complete). Chemists and biologists also use chromatography to
identify the compounds present in a sample, such as plants.
Terms, Concepts and Questions to Start Background Research








adhesion, cohesion forces
capillary action
stationary phase, mobile phase
hydrophilic, hydrophobic
Rf value
paper chromatography
solvent
solution
Questions



Why do different compounds travel different distances on the piece
of paper?
How is an Rf value useful?
What is chromatography used for?
Bibliography


Basic chemistry concepts:
http://www.chem4kids.com
Overview of liquids and capillary action:
http://encarta.msn.com/encnet/refpages/RefArticle.aspx?refid=7615
71486&sec=18#s18
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com


Chromatography:
http://www.doggedresearch.com/chromo/chromatography.htm
BSE Blog:
http://cbse-sample-papers.blogspot.com
Materials and Equipment






water
at least 15 identically sized strips of paper (5 for each pen)
Note: chromatography paper or laboratory filter paper is preferable,
but you can use a paper towel. The problem with paper towels is
that they may be too absorptive and smear the ink. For more
information on which papers work and which don't.
ruler
pencils
at least three different types of black markers (including one
permanent marker), or at least three different colors of marker
(including one permanent marker)
a wide-mouth jar for the solvent
Experimental Procedure
Note: To make sure you can compare your results, as many of your
materials as possible should remain constant. This means that the
temperature, type of water used, size of paper strips, where the ink is
placed onto the paper etc. should remain the same throughout the
experiment.
1. Cut paper strips about one by four inches in area (they must all be
the same size).
2. Take one of the paper strips and use a ruler and pencil to draw a
line across it horizontally two cm from the bottom. This is the origin
line (see illustration, below).
3. Pour a small amount of water into your glass (there should be barely
enough for the paper strip to hang inside of the jar and just touch
the water).
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
4. Using one of the markers, place a small dot of ink onto the line (see
illustration, above).
5. Use the pencil to label the strip, so that you know which marker it
represents.
6. Tape the paper to a pencil and hang it into the jar of solvent so that
the bottom edge is just barely touching (see illustration, below).
7. Let the water rise up the strip until it is almost at the top.
8. Remove the strip from the jar and mark how far the solvent rose
with a pencil.
9. Analyze the ink component(s):
Measure the distance the solvent and each ink component traveled
from the starting position, then calculate the Rf value for each
component (some of the ink components might not have moved at
all!).
10.
Repeat this experiment for each brand or color of marker five
times.
Questions


Did the different inks separate differently? By looking at the
Rf values, can you tell if any of the ink components from the different
markers are the same?
If the ink components separated differently for each marker, why did
this happen (think about the strength of attractions)?
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-DETERMINE THE MASS OF ALUM
CRYSTALS
INTRODUCTION
Aluminium because of its low density, high tensile strength and
resistance to corrosion is widely used for the manufacture of airplanes,
automobiles, lawn furniture as well as for aluminium cans. Being good
conductor of electricity, it is also used for transmission of electricity.
Aluminium foil is used for wrapping cigarettes, confectionery items,
etc. Aluminium is also used for making utensils. The recycling of
aluminium cans and other aluminium products is a very positive
contribution to saving our natural resources. Most of the recycled
aluminium is melted and recast into other aluminium metal products or
used in the production of various aluminium compounds, the most
common of which are the alums. Alums are double sulphates having
general formula X2SO4.M2(SO4)3.24H2O where,
X = monovalent cation such as Na+, K+, NH4+, etc.
M = trivalent cation such as Al+3, Cr+3, Fe+3, etc.
Some important alums and their names are given below:
Potash Alum: K2SO4.Al2(SO4)3.24H2O
Soda Alum Na2SO4.Al2(SO4)3.24H2O
Chrome Alum K2SO4.Cr2(SO4)3.24H2O
Ferric Alum (NH4)2SO4.Fe2(SO4)3.24H2O
Alums are isomorphous crystalline solids, which are soluble in water.
Potash alum is used in paper making, in fire extinguisher, in foodstuffs
and in purification of water. Soda alum is used in baking powders and
chrome alum is used in tanning leather and waterproofing fabrics.
Ferric alum is used in antiseptics. The shape of a potash alum crystal
is octahedral.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
REQUIREMENTS
APPARATUS:





Conical flasks
Filter paper
Piece of aluminium foil
Burner
Funnel
CHEMICALS:



Potassium Hydroxide (KOH)
Sulphuric Acid (H2SO4)
Ethanol (C2H5OH)
THEORY
1. Aluminium metal is treated with hot aqueous KOH solution.
Aluminium dissolves as potassium aluminate, KAl(OH)4, salt.
2Al(s) + 2KOH(aq) + 6H2O(l)
-> 2KAl(OH) (aq) + 3H (g)
4
2
2. Potassium aluminate solution on treatment with dil. sulphuric acid
first gives ppt. of Al(OH)3, which dissolves on addition of small excess
of H2SO4 and heating.
2KAl(OH)4(aq) + H2SO4(aq)
2Al(OH)3(s) + 3H2SO4(aq)
-> 2Al(OH) (s) + K SO (aq) + 2H O(l)
3
2
4
2
-> Al (SO ) (aq) + 6H O(l)
2
4 3
2
3. The resulting solution is concentrated to near saturation and cooled.
On cooling crystals of potash alum crystallize out.
K2SO4(aq) + Al2(SO4)3(aq) + 24H2O(l)
->K SO .Al (SO ) .24H O(s)
2
4
2
4 3
2
PROCEDURE
1. Prepare 50ml of 4M KOH solution.
2. Add small pieces of aluminium foil (about 1 gm) in the conical flask
containing the KOH solution. Since during this step hydrogen gas is
evolved, this step must be done in a well-ventilated area.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
3. After all of aluminium has reacted, filter the solution to remove any
insoluble impurities.
4. Allow the filtrate to cool. Now add slowly conc. H2SO4 until insoluble
Al(OH)3just forms in the solution
5. Gently heat the mixture until the Al(OH)3 ppt. dissolves. Leave the
solution overnight for the crystallization to continue.
6. Take out the crystals and wash them with 50/50 ethanol-water
mixture.
7. Determine the mass of the alum crystals.
OBSERVATIONS
Mass of aluminium metal = 1 gm
Mass of potash alum = 13 gm
Colour = White
Shape of crystals = Octahedral
PRECAUTIONS
1. A few drops of conc. sulphuric acid should be added while preparing
saturated solution of aluminium sulphate to prevent its hydrolysis.
2. Aluminium sulphate solution should be clear and not turbid.
3. Cool the conc. solution slowly to get large crystals. Rapid
disturbance of solution may change the shape, size and quantity of the
crystals.
4. Conc. solution should be cooled undisturbed. A slight disturbance of
solution may change the shape, size.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-DETERMINE THE MASS OF ALUM
CRYSTALS
INTRODUCTION
Aluminium because of its low density, high tensile strength and
resistance to corrosion is widely used for the manufacture of airplanes,
automobiles, lawn furniture as well as for aluminium cans. Being good
conductor of electricity, it is also used for transmission of electricity.
Aluminium foil is used for wrapping cigarettes, confectionery items,
etc. Aluminium is also used for making utensils. The recycling of
aluminium cans and other aluminium products is a very positive
contribution to saving our natural resources. Most of the recycled
aluminium is melted and recast into other aluminium metal products or
used in the production of various aluminium compounds, the most
common of which are the alums. Alums are double sulphates having
general formula X2SO4.M2(SO4)3.24H2O where,
X = monovalent cation such as Na+, K+, NH4+, etc.
M = trivalent cation such as Al+3, Cr+3, Fe+3, etc.
Some important alums and their names are given below:
Potash Alum: K2SO4.Al2(SO4)3.24H2O
Soda Alum Na2SO4.Al2(SO4)3.24H2O
Chrome Alum K2SO4.Cr2(SO4)3.24H2O
Ferric Alum (NH4)2SO4.Fe2(SO4)3.24H2O
Alums are isomorphous crystalline solids, which are soluble in water.
Potash alum is used in paper making, in fire extinguisher, in foodstuffs
and in purification of water. Soda alum is used in baking powders and
chrome alum is used in tanning leather and waterproofing fabrics.
Ferric alum is used in antiseptics. The shape of a potash alum crystal
is octahedral.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
REQUIREMENTS
APPARATUS:





Conical flasks
Filter paper
Piece of aluminium foil
Burner
Funnel
CHEMICALS:



Potassium Hydroxide (KOH)
Sulphuric Acid (H2SO4)
Ethanol (C2H5OH)
THEORY
1. Aluminium metal is treated with hot aqueous KOH solution.
Aluminium dissolves as potassium aluminate, KAl(OH)4, salt.
2Al(s) + 2KOH(aq) + 6H2O(l)
-> 2KAl(OH) (aq) + 3H (g)
4
2
2. Potassium aluminate solution on treatment with dil. sulphuric acid
first gives ppt. of Al(OH)3, which dissolves on addition of small excess
of H2SO4 and heating.
2KAl(OH)4(aq) + H2SO4(aq)
2Al(OH)3(s) + 3H2SO4(aq)
-> 2Al(OH) (s) + K SO (aq) + 2H O(l)
3
2
4
2
-> Al (SO ) (aq) + 6H O(l)
2
4 3
2
3. The resulting solution is concentrated to near saturation and cooled.
On cooling crystals of potash alum crystallize out.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
K2SO4(aq) + Al2(SO4)3(aq) + 24H2O(l)
->K SO .Al (SO ) .24H O(s)
2
4
2
4 3
2
PROCEDURE
1. Prepare 50ml of 4M KOH solution.
2. Add small pieces of aluminium foil (about 1 gm) in the conical flask
containing the KOH solution. Since during this step hydrogen gas is
evolved, this step must be done in a well-ventilated area.
3. After all of aluminium has reacted, filter the solution to remove any
insoluble impurities.
4. Allow the filtrate to cool. Now add slowly conc. H2SO4 until insoluble
Al(OH)3just forms in the solution
5. Gently heat the mixture until the Al(OH)3 ppt. dissolves. Leave the
solution overnight for the crystallization to continue.
6. Take out the crystals and wash them with 50/50 ethanol-water
mixture.
7. Determine the mass of the alum crystals.
OBSERVATIONS
Mass of aluminium metal = 1 gm
Mass of potash alum = 13 gm
Colour = White
Shape of crystals = Octahedral
PRECAUTIONS
1. A few drops of conc. sulphuric acid should be added while preparing
saturated solution of aluminium sulphate to prevent its hydrolysis.
2. Aluminium sulphate solution should be clear and not turbid.
3. Cool the conc. solution slowly to get large crystals. Rapid
disturbance of solution may change the shape, size and quantity of the
crystals.
4. Conc. solution should be cooled undisturbed. A slight disturbance of
solution may change the shape, size.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-TO STUDY THE RATE OF
EVAPORATION OF DIFFERENT LIQUIDS
INTRODUCTION
When a liquid is placed in an open vessel, it slowly escapes into gas
phase, eventually leaving the vessel empty. This phenomenon is
known as evaporation. Evaporation of liquids can be explained in
terms of kinetic molecular model. Although there are strong intermolecular attractive forces which hold molecules of a liquid together,
the molecules having sufficient kinetic energy can escape into gas
phase if such molecules happen to come near the surface. In a sample
of liquid all the molecules do not have same kinetic energy. There is a
small fraction of molecules which have enough kinetic energy to
overcome the attractive forces and escape into gas phase.
Evaporation causes cooling. This is due to the reason that the
molecules, which undergo evaporation, are high-energy molecules;
therefore the kinetic energy of molecules which are left behind is less.
Since the remaining molecules have lower average kinetic energy
therefore, temperature must be lower. If the temperature is kept
constant the remaining liquid will have the same distribution of
molecular kinetic energies and the high-energy molecule will keep on
escaping from the liquid into the gas phase. If the liquid is taken in an
open vessel, evaporation will continue until whole of the liquid
evaporates.
REQUIREMENTS
APPARATUS:
THREE PETRIDISHES OF DIAMETER 10 CM
WITH COVERS
10 ML PIPETTE



STOP WATCH
CHEMICALS:



ACETONE
BENZENE
CHLOROFORM
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
PROCEDURE






Clean and dry the petridishes and mark them as A, B, C.
Pipette out 10 ml of acetone to petridish A and cover it.
Pipette out 10 ml of benzene in petridish B and cover it.
Pipette out 10 ml of chloroform in petridish C and cover it.
Uncover all the three petridishes simultaneously and start the stopwatch.
Note the respective time when the liquids evaporate completely
from each petridish.
OBSERVATIONS
Petridish Mark
A
B
C
Liquid Taken
Acetone
Benzene
Chloroform
Time taken for complete
evaporation
53 min
42 min
30 min
CONCLUSION
The rate of evaporation of the given three liquids is in the order:
Chloroform > Benzene > Acetone
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-TO STUDY THE RATE OF
EVAPORATION OF DIFFERENT LIQUIDS
INTRODUCTION
When a liquid is placed in an open vessel, it slowly escapes into gas
phase, eventually leaving the vessel empty. This phenomenon is
known as evaporation. Evaporation of liquids can be explained in
terms of kinetic molecular model. Although there are strong intermolecular attractive forces which hold molecules of a liquid together,
the molecules having sufficient kinetic energy can escape into gas
phase if such molecules happen to come near the surface. In a sample
of liquid all the molecules do not have same kinetic energy. There is a
small fraction of molecules which have enough kinetic energy to
overcome the attractive forces and escape into gas phase.
Evaporation causes cooling. This is due to the reason that the
molecules, which undergo evaporation, are high-energy molecules;
therefore the kinetic energy of molecules which are left behind is less.
Since the remaining molecules have lower average kinetic energy
therefore, temperature must be lower. If the temperature is kept
constant the remaining liquid will have the same distribution of
molecular kinetic energies and the high-energy molecule will keep on
escaping from the liquid into the gas phase. If the liquid is taken in an
open vessel, evaporation will continue until whole of the liquid
evaporates.
REQUIREMENTS
APPARATUS:
THREE PETRIDISHES OF DIAMETER 10 CM
WITH COVERS
10 ML PIPETTE



STOP WATCH
CHEMICALS:



ACETONE
BENZENE
CHLOROFORM
PROCEDURE
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com






Clean and dry the petridishes and mark them as A, B, C.
Pipette out 10 ml of acetone to petridish A and cover it.
Pipette out 10 ml of benzene in petridish B and cover it.
Pipette out 10 ml of chloroform in petridish C and cover it.
Uncover all the three petridishes simultaneously and start the stopwatch.
Note the respective time when the liquids evaporate completely
from each petridish.
OBSERVATIONS
Petridish Mark
A
B
C
Liquid Taken
Acetone
Benzene
Chloroform
Time taken for complete
evaporation
53 min
42 min
30 min
CONCLUSION
The rate of evaporation of the given three liquids is in the order:
Chloroform > Benzene > Acetone
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-ANALYSIS OF VEGETABLES AND
FRUIT JUICES
AIM
To analyse some fruits & vegetables juice for the contents present in
them.
INTRODUCTION
Fruits and vegetable are always a part of balanced diet. That means
fruits vegetables provide our body 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 oxidixed 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 hvdroxide
Ammonium oxalate
Potassium sulphocynaide solution
PROCEDURE
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
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
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.
Test for Startch:
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.
Observation
Inference
The pH comes out
to be 6.
Orange juice is
acidic.
Absence of blue
black in colour.
Orange juice is
acidic.
No red coloured
precipitates
obtained.
Carbohydrates
absent.
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.
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
Absence of blood
sulphocyanide solution .Blood red colours shows the
red colour.
presence of iron.
Iron is absent.
Test for Calcium:
Take 2 ml of juice add Ammonium chloride and
ammonium hydroxide solution. Filter the solution and to Yellow precipitate is
Calcium is present.
the filterate add 2 ml of Ammonium Oxalate solution.
obtained.
white ppt or milkiness indicates the presence of calcium.
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.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
AIM-ANALYSIS OF VEGETABLES AND
FRUIT JUICES
AIM
To analyse some fruits & vegetables juice for the contents present in
them.
INTRODUCTION
Fruits and vegetable are always a part of balanced diet. That means
fruits vegetables provide our body 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 oxidixed 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 hvdroxide
Ammonium oxalate
Potassium sulphocynaide solution
PROCEDURE
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com
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
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.
Test for Startch:
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.
Observation
Inference
The pH comes out
to be 6.
Orange juice is
acidic.
Absence of blue
black in colour.
Orange juice is
acidic.
No red coloured
precipitates
obtained.
Carbohydrates
absent.
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.
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
Absence of blood
sulphocyanide solution .Blood red colours shows the
red colour.
presence of iron.
Iron is absent.
Test for Calcium:
Take 2 ml of juice add Ammonium chloride and
ammonium hydroxide solution. Filter the solution and to Yellow precipitate is
Calcium is present.
the filterate add 2 ml of Ammonium Oxalate solution.
obtained.
white ppt or milkiness indicates the presence of calcium.
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.
PRADEEP SHARMA, INSTITUTE OF COMPETITIVE STUDIES, SECTOR – 15 , SONEPAT
CONTACT NUMBER : 0130 – 2231322 , E – mail : picsedu4iit@gmail.com