Question

A chemist measures the energy change ?H during the following reaction:

Answer 1

Answer:

Endothermic

It absorbs heat

1.20 × 10³ kJ

Explanation:

Let's consider the following thermochemical equation.

2 H₂O(l) → 2 H₂(g) + O₂(g)    ΔH = 572 kJ

Since ΔH > 0, the reaction is endothermic, that is, it absorbs heat when H₂O reacts.

572 kJ are absorbed when 36.03 g of water react. The heat absorbed when 75.8 g of H₂O react is:

75.8 g H₂O × (572 kJ/36.03 g H₂O) = 1.20 × 10³ kJ