ASSUMPTION UNIVERSITY
Faculty of Engineering
Physics Laboratory
Name:
Code:
Sec:
Experiment:
: Specific heat capacity of a given object (metal solid)
Objective:
: To determine the specific heat capacity of a given object by the method of mixture.
Apparatus:
Theory:
: Copper calorimeter with jacket, metal solid (given object), thermometer, water,
beaker, nylon wire, hot plate and laboratory balance.
:
Heat is energy transferred from one substance to another because of temperature
difference. The unit of heat is calorie (cal) or British thermal unit (Btu.).
1 cal = 4184J and 1Btu = 1054 cal
Temperature is a quantitative description of hotness and coldness.
A thermometer is an instrument that measures temperature. The unit of temperature
is degree Celsius (oC) or degree Fahrenheit (oF). The Celsius and Fahrenheit
temperature scales are based on the freezing temperature of water (0oC = 32 oF) and
boiling temperature of water (100oC = 212 oF)
The amount of heat needed to increase the temperature of a quantity of matter depends
on the mass of material, the temperature changes, and a property of the material
called the specific heat capacity. The amount of heat is denoted by Q and it can be
calculated as follow.
The amount of heat Q = m c Δ t
Where, m = mass of material,
c = specific heat capacity of metal,
Δ t = temperature changes.
The specific heat capacity of a substance is defined as the heat, in joules, required to
raise the temperature of 1 kg of it by 1oC.
Assuming there is no heat exchange between the calorimeter and the surroundings,
we can use the law of heat exchange,
“Heat lost = Heat gained”.
[If the heated metal solid is mixed with water inside a calorimeter.]
If we denoted, mo = Mass of the given object (metal solid)
m1 = Mass of calorimeter with stirrer
m2 = Mass of calorimeter with stirrer and water
m2  m1 = Mass of water
t0 = Temperature of the water in calorimeter
t1 = Temperature of the boiling water
t2 = Highest steady temperature
(After mixing heated metal solid and water inside the calorimeter)
C = Specific heat capacity of the given object (metal solid)
C1 = Specific heat capacity of the calorimeter and stirrer ( 390 j / kgoC )
C2 = Specific heat capacity of water ( 4184 j / kgoC )
Heat lost by the metal solid = mo C (t1 t2) joules.
Heat gained by the calorimeter with stirrer and water = m1C1 (t2 t0) + (m2  m1) C2 (t2 t0) joules.
Law of heat exchange,
Heat lost = Heat gained
mo C (t1 t2) = m1C1 (t2 t0) + (m2  m1) C2 (t2 t0)
Specific heat capacity of the given object (metal solid) can be found as follow,
C
{m1C1  (m2  m1 )C2 }(t 2  t 0 )
j / kgoC
mo (t1  t 2 )
Instructions
1. Measure the mass of the given object (metal solid) (mo) by using laboratory balance.
2. Start boiling the water in the beaker.
3. Tie the metal solid by using nylon wire and suspend it in the boiling water about 10 minutes.
4. Measure the mass of calorimeter with stirrer (m1) while you are waiting for the water to boil.
5. Measure the mass of calorimeter with stirrer and water (m2) after filling the calorimeter with
cold water about half of the calorimeter.
6. Put the calorimeter with stirrer into the jacket.
7. Record the temperature of the water in the calorimeter (t0), read the temperature with
estimation up to 0.1oC.
8. Record the temperature of the boiling water (t1) in oC.
9. Remove the given object from boiling water, shake it briskly, and transfer quickly it into the
calorimeter.
10. Gently stir the water using stirrer continuously to reach the highest steady temperature (t2).
[This process is very much important to get the highest steady temperature, you need to
observe closely all the time up to the highest steady temperature and read the temperature
with estimation up to 0.1oC. If you miss your observation process for a moment you can miss
the highest steady temperature.]
Assignment questions
1. Can the above method be used to determine the specific heat capacity of cork? Give reasons to
support your answer.
2. In this experiment, why must the metal solid be transferred quickly into the calorimeter?
3. One student commented that it was not necessary to shake the water off the metal solid before
transferring it into the calorimeter. Is he right or wrong? Explain.
4. What is specific heat capacity of an object?
5. What is the law of heat exchange?
Name:
Code:
Sec:
Data taking
(Type of metal ……………………..
)
Mass of the given object (metal solid) .................................. mo =
g=
Mass of calorimeter with stirrer ............................................. m1 =
Mass of calorimeter with stirrer and water ............................. m2 =
Mass of water ...............................................................(m2  m1) =
Temperature of the water in calorimeter .................................. t0 =
Temperature of the boiling water .............................................. t1 =
Highest steady temperature ....................................................... t2 =
(After mixing heated metal solid and water inside the calorimeter)
Calculation of specific heat capacity of an object
C
{m1C1  (m2  m1 )C2 }(t 2  t 0 )
mo (t1  t 2 )
o
C
kg