The Specific Heat Capacity of a Liquid by the Method of Cooling

Introduction:

This experiment will be using the calorimeter to measure the specific heat capacity of paraffin and water by the method of cooling. Specific heat capacity is to measure the heat energy required to increase the temperature of a unit quantity of substances by a certain temperature interval and is the S.I unit is J g-1K-1. Thus, heat is measured by monitoring the temperature difference between heat transfer fluid and process fluid. Also, using calorimeter in this experiment is because we need to measure the heat of chemical reactions or physical changes as well as heat capacity. Firstly, a blackened copper calorimeter with copper lid to fit is bored with two holes to take a thermometer (0-100。C in 0.1.C) and a copper stirrer. Secondly, the outer jacket should place in double-walled and should fill with a mixture of water and ice. The lid of the calorimeter is to reduce heat losses by the process of convection and evaporation. As for theory, it used to determine the formula of

[ m0c0+(m1-m0)c ] t1

[m0c0+(m2-m0)cw] tw

Lastly, hypothesis of this experiment is the differences of the specific heat capacity have difference duration of time to cool down. Therefore, water has higher capacity then paraffin oil; it needs to take a longer time to cool down in a constant temperature, 40.C.

Objectives:

To determine the relationship of the specific heat capacity and the time taken to cool down in between of water and paraffin oil.

Procedure:

1. Firstly, weight the mass of the calorimeter with the lid and the stirrer.

2. Secondly, assemble the apparatus follow as in the diagram and meanwhile heat up

the water in a beaker to about 70.C.

3. Thirdly, the calorimeter is removed from the apparatus and it is filled with 125ml of heated water in it to within a centimeter of the top. Thermometer, stirrer and lid is replaced and put the whole back in to the cooling chamber (double-walled contained the mixture of ice and water).

4. Water was stirred frequently; when the temperature decrease to 60.C, record the temperature in one minute intervals down to 40.C by using a stopwatch.

5. Thermometer is removed and the calorimeter and its contents, including the lid and the stirrer need to re-weight the mass of it.

6. Result of the first experiment is recorded in the table.

7. Then, the calorimeter is rinsed with water and wiped it till dry.

8. Later on, heated up the paraffin oil in a beaker to about 70.C and poured