Question

Dissolving potassium chlorate (KClO3) is even more endothermic than potassium chloride.

Answer 1

Answer:

The mass of KClO₃ that will absorb the same heat as 5 g of KCl is 3.424 g

Explanation:

Here we have

Heat of solution of KClO₃ = + 41.38 kJ/mol.

Heat of solution of KCl (+17.24 kJ/mol)

Therefore, 1 mole of KCl absorbs +17.24 kJ during dissolution

Molar mass of KCl = 74.5513 g/mol

Molar mass of KClO₃ = 122.55 g/mol

74.5513 g of KCl absorbs +17.24 kJ during dissolution, therefore, 5 g will absorb

$\frac{17.24}{74.5513 } \times 5 \, \, kJ \, or \, 1.156 \, kJ$

Therefore the amount of KClO₃ to be dissolved to absorb 1.156 kJ of energy is given by

122.55 g of KClO₃ absorbs + 41.38 kJ, therefore,

$\frac{1.156}{41.38} \times 122.55 \, g = 3.424 \, g$

Therefore the mass of KClO₃ that will absorb the same heat as 5 g of KCl = 3.424 g.