Calorimetry (SQA National 5 Chemistry): Revision Note

Calorimetry experiments

• Different fuels release different quantities of energy when they burn

• The amount of heat energy released by a fuel can be measured using a technique called calorimetry

• A simple calorimetry experiment involves using the heat from a burning fuel to raise the temperature of a known mass of water

  • The full practical details of this experiment are covered in the Practical Techniques for Calorimetry revision note

• Two measurements are required for this experiment:

  • The mass of water being heated (m)

  • The temperature change of the water (ΔT)

• These measurements, along with the specific heat capacity of water (c), are used in the E_h = cmΔT formula to calculate the heat energy released

Calorimetry calculations

• To calculate the quantity of heat energy released, we use the formula given on page 3 of the SQA Data Booklet

The heat energy formula

E_h = cmΔT

• Values in the equation:

  • E_h = the heat energy absorbed by the water (in kilojoules, kJ)

  • c = the specific heat capacity of the substance being heated

    • For water, this value is 4.18 (found in the Data Booklet)

  • m = The mass of the substance being heated (in kilograms, kg)

  • ΔT = The change in temperature (in degrees Celsius, °C)

    • ΔT = T_(final) - T_(initial)

How to use the heat energy formula

• List all the variables (E_h, c, m, ΔT), identifying the one you need to find

  • Convert all masses to kilograms (kg) by dividing by 1000

  • Calculate the temperature change, if required

• Substitute the known values into the formula

• Rearrange the formula for the unknown value

• Solve the formula for the unknown value