Experiment: Determine the specific heat of a solid using the method of mixtures.
Specific heat: The amount of heat required for a unit mass of substance to raise its temperature by 1°C is defined as specific heat.
The unit of specific heat is cal gr–1 °C–1 or J kg–1 °C–1 and it is read as calorie per gram per degree celsius or Joule per kilogram per degree celsius.
Heat lost or gained by a body: For a body of mass m, specific heat s and change in temperature change Δt,
Heat gained = ms Δt (Δt is rise in temperature)
Heat lost = ms Δt (Δt is fall in temperature)
Heat-exchange takes place between solids, liquids and surroundings. Whatever heat is lost by a hot body is taken up by the cooler ones in its contact because energy is conserved. This is known as principle of heat exchange which states that,
Heat gained by a cold body = heat lost by a hot body
This can be used to find the specific heat of solids and liquids.
Method of Mixture: States that if a hot solid is placed in a cold liquid with which it has no chemical reaction then the heat lost by the solid body is equal to heat gained by the liquid, assuming there is no loss of heat to the surroundings.
Calorimeter with insulated box and stirrer, heating arrangement, brass bob, two thermometers, measuring glass cylinder, cotton thread, spring balance to find the mass of bob
1. Clean and weigh the calorimeter and stirrer using the spring balance.
2. Place the calorimeter in its insulated box.
3. Measure 60 mL of water using the measuring cylinder and pour it carefully in the calorimeter.
4. Fix the thermometer in the stand and note the temperature of this cold water.
5. Tie a thread to the brass bob; heat it in boiling water for a few minutes. Note the temperature of boiling water by second thermometer already fixed in it, in another stand.
6. Quickly transfer the brass bob info the water in the calorimeter; cover the lid; and stir.
7. The temperature of water will rise and then become steady. Thereafter it slowly falls on account of loss of heat to the surrounding.
8. Note the steady, final temperature of water.