IB Specific Heat Capacity Lab

∴ Specific heat capacity of bob = (Heat gained by water + Heat gained by calorimeter) ÷ (Mass of bob × Temperature change of bob).

VARIABLE:

• Independent (manipulated) variables

1. Initial temperature of solid
2. Mass of metal bob and calorimeter

• Dependent (responding) variables

1. Final temperature of metal bob, calorimeter and water
2. Mass of water

• Controlled variables

1. Initial temperature of water (22°C) and calorimeter (41.35°C)
2. Room temperature (air-condition was kept at a fixed temperature)

• Unknown variable

Specific heat capacity of the solid (metal bob)

HOW TO CONTROL VARIABLES:

• The same calorimeter, thermometer and bob are used for every trial, so that the specific heat capacity which is verified remains the same.
• Experiment is conducted in an air conditioned room to maintain the room temperature.

METHOD:

1. I kept the metallic bob into the hot water bath to heat it.
2. During the bob was being heated by hot water bath I took an empty calorimeter and weighed it on the Top-pan balance.
3. I half filled the calorimeter with tap water and weighed it again.
4. I left the half filled calorimeter for few minutes in order to reach the state of equilibrium with room temperature.
5. After some time I measured the temperature of the water from the calorimeter.
6. After keeping the bob for some time, I recorded the temperature of the water bath with the help of thermometer and then quickly took out the bob with clapper and kept it into the half filled calorimeter.
7. I covered the calorimeter with the lid and used stirrer to acquire equilibrium temperature of the whole body.
8. I recorded the new equilibrium temperature of the body and recorded all the necessary values.
9. All the values were recorded.
10. I repeated the process for another two times using same Bob.

DATA COLLECTION AND PROCESSING (DP)

DATA COLLECTION:

DATA PROCESSING and PRESENTATION:

• Heat gained = Heat lost.
• M C δΤ = M C δΤ
• M C (TFinal – TInitial) = M C (TInitial – TFinal)
• MB × CB (T3 – T2) = (Mw × Cw (T2 – T1)) + (MC × CC (T2 – T1))
• CB = [(Mw × Cw (T2 – T1)) + (MC × CC (T2 – T1))] ÷ MB (T3 – T2)
• CB = (HW + Hc) ÷ MB × δTB

∴ Specific heat capacity of bob = (Heat gained by water + Heat gained by calorimeter) ÷ (Mass × Temperature change of bob).

Trial 1

Trial 2

Trial 3

CONCLUSION AND EVALUATION (CE)

CONCLUSION

Total heat gained by water and calorimeter is directly proportional to the initial temperature of Solid which is directly proportional to the temperature of Water Bath:

Heat gained by Water and Calorimeter (Hs)  Initial temperature of Solid (Bob) (ΤB)  Temperature of Water Bath (T3)

Therefore, change in the total heat gained by water and calorimeter is directly proportional to change in the initial temperature of Solid which is directly proportional to the temperature of Water Bath:

δHs  δΤB  δT3

Graph: Temperature of Water Bath V/s Total heat gained by Water and Calorimeter

As the slope is positive (+35.1), Temperature of Water Bath is directly proportional to Total heat gained by Water and Calorimeter.

Hence, I have proved my hypothesis.

Average Specific Heat Capacity of the metal bob:

Literary value of Specific heat capacity of Brass: 377 J kg-1 K-1 

Experimental value of Specific Heat Capacity of Brass: 335.66 J kg-1 K-1 ± 88.4

Hence, the experimental value for the Specific Heat Capacity of the Brass Bob matches the literary value of the Specific Heat Capacity of the Brass, thus Equation of Thermal Equilibrium holds true:

M C δΤRISE = M C δΤFALL

Calculating Errors:

EVALUATION

Hence, according to my experiment the specific heat capacity of metal bob is 335.66 J kg-1 K-1. The value may contain some error due to following reasons:

1. Efficiency of the apparatus wasn’t up to the mark.
2. Unexpected interruptions delayed the experiment in between.
3. Heat loss in any spilling of water, may be while dropping in the solid.
4. Heat loss from apparatus to the atmosphere.
5. Non uniform heating of water may cause incorrect readings for temperature of water bath.