Question

1. A calorimeter contains 143 g of water at 22.5°C. A 12 g sample of NaCl is added to the water in the calorimeter. After the solid has dissolved, the temperature of the water is 21.6°C. Calculate the enthalpy of solution for dissolving sodium chloride. Assume that no heat is lost to the calorimeter or the surroundings and that the specific heat of the solution is the same as that of pure water.

Answer 1

Answer:

Enthalpy of solution is 583.67 J

Explanation:

The mass of water is 143 g

The mass of NaCl added = 12g

Total mass of solution will be = $massofwater+massofNaCl=143+12=155g$

The specific heat of solution = specific heat of water = 4.184 J /g °C

The initial temperature = 22.5°C

Final temperature =21.6°

The change in temperature = $Initial-Final=22.5^{0}-21.6^{0}=0.9^{0}$

The enthalpy of solution will be equal to the heat change in the solution.

The heat change of solution will be calculated as:

$Heat=massofsolutionXspecificheatXchangeintemperature$

$Heat=155x4.184X0.9=583.67J$

Thus the enthalpy of solution is 583.67 J (Endothermic reaction)