Question

What quantity in moles of H₂ are required to give off 2501 kJ of heat in the following reaction?

A) 0.057 moles
B) 0.083 moles
C) 0.112 moles
D) 0.125 moles

Answer 1

To find the moles of H₂ that produce 2501 kJ, a proportion based on the reaction's enthalpy change is used, resulting in approximately 13.543 moles. This does not match any of the given options.

Step-by-step explanation:

To calculate the quantity in moles of H₂ required to give off 2501 kJ of heat in the reaction, we first need the relationship between the moles of H₂ and the energy given off provided by the reaction's enthalpy change (ΔH).

The provided information indicates that:
1 mol H₂ → 1 mol Cl₂ ⇒ 2 mol HCl releases -184.6 kJ of heat.

From this, we can set up a proportion to determine the number of moles needed to release 2501 kJ:

− 184.6 kJ / 1 mol H₂ = 2501 kJ / x mol H₂

Now, solve for x:

x = (1 mol H₂ × 2501 kJ) / − 184.6 kJ
x ≈ 13.543 moles of H₂

The options provided in the question do not match this result, hence there may be a mistake in the options or the interpretation of the heat value. The calculated moles do not correspond to any of the choices A to D.