Question

How many gram of water is decomposed by 429 kJ of heat if heat of decomposition of water is 286 kJ mol^-1?

Options

• 27 g

• 40 g

• 36 g

• 22.5 g

Answer 1

27 g

Explanation:

For 18 g of H₂O = 286 kJ of heat is required.

∴ x g of H₂O = 429 kJ of heat is required.

∴ x = `(429 xx 18)/286` = 27 g