Question

When pure sodium hydroxide is dissolved in water, heat is evolved. In a laboratory experiment to measure the molar heat of solution of sodium hydroxide, the following procedure was followed. To a calorimeter containing 3.00 × 10^2 g of water at 20.00 °C, 10.65 g of NaOH, also at 20.00 °C was added. The temperature of the solution, which was monitored by a digital thermometer with negligible heat capacity, increased to 28.50 °C. If the specific heat of the mixture is 4.184 J g^-1 °C^-1, and the small heat capacity of the calorimeter is ignored, what is the heat evolved, per mole of sodium hydroxide?

Answer 1

The temp. increase was 8.50 degrees C. (my b)
It requires 4.184J to increase the temp. of a 1g solution by 1 degrees C.
Total heat required is 16,143J.
Molar Mass NaOH is 40g/mol
Evolved heat/mol NaOH = 51,045J.