Question

Consider the hypothetical thermochemical equation

3 A + B → 2 C

for which ΔH = 57.7 kJ/mol.

If you have 5.30 moles of A, what quantity of heat, in kJ, would be absorbed?

Answer 1

The quantity of heat absorbed when 5.30 moles of A react according to the thermochemical equation is calculated using the enthalpy change and stoichiometry, resulting in a direct proportion calculation based on the given ΔH value.

Step-by-step explanation:

The student's question involves calculating the quantity of heat absorbed during a reaction using the provided thermochemical equation 3 A + B → 2 C where ΔH = 57.7 kJ/mol. To find the heat absorbed when 5.30 moles of A react, we must use stoichiometry and proportionality based on the molar ratios presented in the thermochemical equation. Assuming that reactions are run at constant pressure, ΔH represents the enthalpy change for the reaction.

Since ΔH indicates the heat change for the reaction of 3 moles of A, to find the heat absorbed for 5.30 moles of A, we apply direct proportion:

The enthalpy change (ΔH) for 3 moles of A is 57.7 kJ. Therefore, for 5.30 moles of A, the heat absorbed (q) can be calculated as:
q = (5.30 moles A) / (3 moles A) × 57.7 kJ/mol