Lab E   Specific Heat
equipment
Object
To measure the specific heat of a metal specimen.

Theory

Temperature is a measurement of the relative hotness or coldness of a body.  To raise the temperature of a body we add heat to the body.  It is found that for large ranges of temperature, if a material doesn't change state, the heat added to a body is directly proportional to the change in the body's temperature and to the mass of the body.  Therefore,
 
(1)  DQ = c m DT

where DQis the heat added to the body, m the mass of the body,  D the change in temperature and the constant of proportionality c (which only depends on the material) is called the specific heat.
In the equation the units we will use are:
 
Quantity
DQ
m
DT
c
Units
[ cal ] 
[ g ]
[ 0C ]
[ cal/g0C ]

If we bring several bodies together which are at different temperatures, the heat gained by the cold bodies will equal the heat lost by the hot bodies and all bodies will reach the same final temperature.
If a metal specimen of mass M and temperature Tm (Tm = 1000C in the experiment) is placed in an insulated container (calorimeter) containing water which is at an equilibrium temperature Tc the combination will reach a final equilibrium temperature TF.  From this we can write,
 
(2)  M c (Tm-TF) = MWcW(TF-Tc) + Mccc(TF-Tc)

where MW is the mass of water,  M the mass of the calorimeter, cW  is the specific heat of the water, cc the specific heat of the calorimeter and  is the specific heat of the metal specimen.
Procedure
 
1.   Weigh the specimen.  Weigh and record the calorimeter inner cup and stirrer.  Fill the cup with water and a little ice so it will cover the specimen and again weigh the cup (filled with water ) and stirrer.
2.   Fill the steam generator with water, place the specimen in the steam jacket and heat the specimen to steam temperature.  Heat aluminum specimen for at least 10 minutes and copper specimen for at least 20 minutes to have the temperature Tm = 1000C.  Go to next point of procedure when the heating is almost finished.
3.   Allow calorimeter, water and ice to reach a constant stable temperature by placing the assembly in the housing, stirring gently and recording the temperature every 20 seconds.  All the ice should be melted.
4.   Put the calorimeter near the steam chest and lower the specimen into the calorimeter.  Try not to splash the water.  Move the calorimeter away from the stem generator and turn off the steam.
5.   Stir gently and record the temperature every 20 seconds until a final steady state temperature is reached.
6.   Do the data analysis.
7.   If time permits repeat steps 1 through 6 but try and arrange and initial temperature for the calorimeter so it is as much below room temperature as the final temperature will be above room temperature.

 Data Analysis

1.   Calculate the heat gained by the calorimeter, water and stirrer.
2.   Find the specific heat of the specimen.
CONCLUSION




State the specific heat of the specimen.  Compare this with a published result.