RP2-Enthalpy change (copper sulfate)

• Equipment: anhydrous copper sulfate, weighing boat, mass balance, measuring cylinder, polystyrene cup, thermometer, glass rod, stopwatch.
• Set up: Using a measuring cylinder, add 25 cm^3 of deionised, room temperature water to a polystyrene cup and record the temperature every minute for three minutes. Weigh by difference 5 g of anhydrous copper sulfate.
• Method: Pour the anhydrous copper sulfate into the water and stir. After one minute, record the temperature and then continue recording every minute for 15 minutes.
• Graph: Plot a graph of temperature against time and draw two separate lines of best fit - one for before and one for after the addition of the copper sulfate. Extrapolate both to the fourth minute.
• Analysis: Use the graph to determine the temperature change at the fourth minute.
• Safety: Anhydrous copper sulfate could be an irritant - wash hands if spilt on them.