RP2- Enthalpy Change

Question 1

A 5.00 g sample of potassium chloride was added to 50.0 g of water initially at 20.0 °C. The mixture was stirred and as the potassium chloride dissolved, the temperature of the solution decreased.
Describe the steps you would take to determine an accurate minimum temperature that is not influenced by heat from the surroundings. (4)

Answer 1

• Start a clock when KCl is added to water
• Record the temperature every subsequent minute for about 5 minutes
• Plot a graph of temperature vs time
• Extrapolate back to time of mixing + determine the temperature