Physics – 2.2.2 Specific heat capacity | e-Consult

Apparatus:

• A known mass of the liquid
• A calorimeter (e.g., a Styrofoam cup inside a beaker)
• A thermometer (capable of measuring to 0.1°C)
• A hot plate or Bunsen burner
• A balance
• A beaker of water (for the calorimeter)

Procedure:

1. Weigh the liquid and record its mass (m).
2. Measure the mass of water in the calorimeter and record it.
3. Heat the liquid in a separate container on the hot plate or using the Bunsen burner until it reaches a known high temperature (T_hot). Monitor the temperature with the thermometer.
4. Quickly transfer the hot liquid into the calorimeter containing the measured mass of water.
5. Stir the water gently and monitor the temperature of the water and the liquid mixture.
6. Record the maximum temperature reached by the water-liquid mixture (T_final).

Calculation:

Assuming no heat is lost to the surroundings, the heat lost by the liquid is equal to the heat gained by the water and the calorimeter. The heat gained by the water is calculated as: Q = m_water × c_water × (T_final - T_initial), where c_water is the specific heat capacity of water (4.18 J/g°C) and T_initial is the initial temperature of the water. The heat gained by the calorimeter is calculated as: Q_calorimeter = m_calorimeter × c_calorimeter × (T_final - T_initial), where c_calorimeter is the specific heat capacity of the calorimeter material. The heat lost by the liquid is calculated as: Q_liquid = m × c_liquid × (T_hot - T_final), where c_liquid is the specific heat capacity of the liquid (the value we want to determine). Equating heat lost and heat gained and rearranging gives: c_liquid = (m × (T_hot - T_final)) / (m_water × c_water × (T_final - T_initial) + m_calorimeter × c_calorimeter × (T_final - T_initial)).