Measuring Heat Transfer

Heat is transferred from areas of higher kinetic energy (HOT) to lower kinetic energy (COLD).  Kinetic energy is transferred as random particle motion.

The heat transfer may be measured by allowing the heat to be transferred to water in a calorimeter.  Measuring the mass of the water and its change in temperautre allows the amount of heat transfer to be calculated using the equation.  q = m C ΔT


Sample Calculation.

A reaction occurs in a test tube placed in the water in calorimeter. 

Data. 

75.0 mL of water in calorimeter

initial temperature of the water 19.8 ° C

final temperature of the water 22.2 ° C

The reaction transfers heat to the water in calorimeter causing the temperature to increase - increasing the kinetic energy.

q = m C ΔT

q = 75.0 g (4.18 J/g°C)(22.2°C - 19.8°C)

q = 752.4 J = 752 Joules to three significant digits