HS 1st year : Chemistry chapter 5 Thermodynamics experiments

 

Experiment 1: Determination of the Mechanical Equivalent of Heat (J) using Joule’s Calorimeter

Apparatus Required:
Joule’s calorimeter, battery, ammeter, voltmeter, stopwatch, rheostat, key, and connecting wires.

Procedure:

1. Arrange the Joule’s calorimeter with stirrer and heating coil inside it.

2. Measure the mass of water in the calorimeter.

3. Note the initial temperature of the water.

4. Complete the circuit using the battery, ammeter, voltmeter, and key.

5. Close the key and start the stopwatch simultaneously.

6. Keep the current flowing for a known time interval.

7. Note the final temperature of the water.

8. Use the known values of voltage (V), current (I), and time (t) to calculate the heat produced:

   $$H = VIt \, \text{joules}$$

9. Compare the calculated heat with the heat gained by the water:

   $$H' = mc\Delta T$$

10. The mechanical equivalent of heat $J = \frac{H}{H'}$

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Experiment 2: Determination of Specific Heat of a Liquid by the Method of Mixtures

Apparatus Required:
Calorimeter, thermometer, stirrer, water, and the liquid under test.

Procedure:

1. Measure and record the mass of the calorimeter and water.

2. Note the initial temperature of water.

3. Heat the liquid to a known temperature.

4. Pour the hot liquid into the calorimeter containing water.

5. Stir gently and note the final temperature.

6. Use the principle of calorimetry:

   $$\text{Heat lost by liquid} = \text{Heat gained by water + calorimeter}$$

7. Calculate the specific heat of the liquid using the formula.