When a 5.00 g sample of KBr is dissolved in water in a calorimeter that has a total heat capacity of 3.10 kJ ⋅ K − 1 , the temperature decreases by 0.270 K . Calculate the molar heat of solution of KBr .

Explanation:

Using the law of conservation of energy, the heat of solution of KBr equals the heat absorbed or released by the calorimeter.

In this case, the temperature of the calorimeter decreased, then it released heat that the sample of KBr absorbed. This is, then, an endothermic change.

The heat released by the calorimeter equals its heat capacity multiplied by the change in temperature:

Then:

The molar heat of solution is the heat absorbed by the sample divided by the number of moles in the sample.

Convert 5.00 g of KBr into number of moles

Divide the heat absorbed by the number of moles

You must round to 3 significant figures: 19.9J/mol ← answer

a is the answer to this question

explanation: