CHEMISTRY PROJECT CLASS 12

1. Aim of Project-
The aim of this project is to study the
effect of various factors an the rate of
evaporation of liquids

2. Introduction
Evaporation is the process whereby atoms or molecules
in a liquid state or solid state if the substance sublimes
gain sufficient energy to enter the gaseous state.
Factors affecting evaporation:
• 1. Temperature:
• On increasing the temperature the rate of
evaporation also increases.
• At higher temperatures, the molecules are moving
faster; therefore, it is more likely for a molecule to have
enough energy to break away from the liquid to
become a gas.

3. • Nature of liquid:
• The magnitude of the intermolecular forces in
a liquid determines the rate of evaporation.
Weaker the intermolecular forces ,higher the
rate of evaporation.
• Larger the surface area of a liquid, more are
the chances for the molecules to leave a
liquid, to under go evaporation.
• Presence of air currents:
Presence of air currents over the surface of a
liquid take away the molecules of the liquids
which have left the surface thereby preventing
condensetion.

4. To compare the rates of evaporation of
different liquidsRequirements-
Requirements-
• Four weighing bottles
• Weight box
• Balance 10 ml pipette
• Stop watch

5. Chemicals-
a. Water
b. Acetone
c. Ethyle
d. Benzene

6. Procedure-
1. Clean and dry four weighing bottles and label them as A,B,Cand D
2. Take 10 ml of distilled water with the help of pipette and transfer
to weighing bottle labelled as A.
3. In the same way transfer 10ml of acetone to bottle C and 10ml of
benzene to bottle D and stopper them properly.
4. Weigh bottle A containing water. Remove the stopper and start
stop watch. Close the bottle with stopper after 30 min and weigh
it again. Calculate the difference in weights which gives the weight
of water evaporated in 30 min.
5. Repeat the same procedure for bottle B,C an D containing ethyl
alcohol , acetone and benzene respectively. Note the weight of
each liquid which under goes evaporation in each case.

7. Observation-
Room temperature=
Time alloted for evaporation=1800sec
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S No
Liquid Weighing of bottle+liquid weighing of Rate of
Taken evaporated evaporation
Before evap. After evap. (W1-W2)g W1-W2/1800g/s
1 Water
2 Ethyl
alcohol
3 Acetone
4 Benzene

8. OBSERVATION-
ACETONE HAS HIGHER RATE OF
EVAPORATION. THE RATE OF
EVAPORATION ARE IN THE ORDER-
ACETONE>ETHYL ALCOHOL> BENZENE >
WATER
.

9. To study the effect of temperature on
the rate of evaporation of a liquid
Requirements-
• Two 5cm diameter petridish
• 10 ml pipette
• Thermostar
• Iron stand
• Stop watch
• acetone

10. Procedure-
1. Wash and clean two petridish of equal size (0.5 cm
diameter). Dry them in an air oven and label as A and
B
2. Pipette out 10ml of acetone in the two petridish,
cover them with a lid or cover.
3. Set up a thermstat at 15-20 C higher than the room
temperature, place the dish A in the thermostat.
Remove the cover and start stop watch. Note the time
taken for complete evaporation.
4. Uncover the petridish B at room temperature, start
the stop watch and note the time taken for complete
evaporation.

11. Observation-
Volume of acetone taken in each petri dish=10ml
Conclusion-Acetone placed in the thermostat
evaporates first showing the rate of evaporation
increases with rise of temperature.
S No. Petridish Temperature Time Rate of evaporation V/t
1 A C sec
2 B C sec

12. To study the effect of surface area on
the rate of evaporation of a liquid
Requirements-
• Three petri dishes of different size(2.5cm,
5.0cm, and 7.5cm)diameter,
• 10ml pipette
• Stop watch
• acetone

13. Procedure-
1. Take three petridishes of diameter 2.5cm,
5cm, and 7.5cm. Clean and dry them. Label
them as A,B,C.
2. Take 10ml of acetone in petridish A and start
the stop watch immediately. Note the time
taken for complete evaporation.
3. Repeat the same experiment for petri dish B
and C. Note the time taken for complete
evaporation in each case.

14. Observation-
Volume of acetone taken in each petri dish
=10ml
Petridish mark Diameter of petri dish Time Taken
A 2.5cm sec
B 5.0cm sec
C 7.5cm sec

15. Conclusion-
The time taken for complete evaporation in the
three petridishes is in the order-
2.5cm>5cm>7.5cm
Therefore, the rate of evaporation is in the
order-
2.5cm>5cm>7.5cm
This shows the rate of evaporation increases
with increase in surface area.

16. To study the effect of air current on
the rate of evaporation-
Requirements-
• Two petri dishes
• Acetones
Procedure-
1. Take 10ml of acetone in each of the two petri dishes
of the same size.
2. Keep one dish in the place where there is no fan and
the other under the fan.
3. Start the stop watch and note the time taken for the
complete evaporation of acetone in both the dishes

17. Observation-
Conclusion-
The observation clearly indicate that the liquid
under the fan evaporates faster. This shows
that the rate of evaporation increases with the
flow of air current on the surface of the liquid.
Petridish mark Condition Time Taken
A without fan 30 sec
B with fan 20 sec

18. Bibliography-
Reference taken from class 11th books
WEBSITES-
 www.encyclopedia.com
 www.google.com
 www.wikipediea.com