Final answer:
Approximately 53 grams of C₆H₆ must decompose to transfer 430 kJ of heat.
Step-by-step explanation:
To calculate the grams of C₆H₆ required to transfer 430 kJ of heat, we need to consider the enthalpy change in the given chemical equation: C₆H₆ (l) → 3 C₂H₂ (g) ΔH = 630 kJ.
We can use stoichiometry to determine the molar quantity of C₆H₆ required: 1 mol of C₆H₆ produces 630 kJ of heat. Therefore, to transfer 430 kJ, we can set up a proportion:
(1 mol C₆H₆ / 630 kJ) = (x mol C₆H₆ / 430 kJ)
Solving for x gives us x = (1 mol C₆H₆ * 430 kJ) / 630 kJ = 0.68 mol C₆H₆.
Finally, we can convert this molar quantity to grams using the molar mass of C₆H₆: 0.68 mol C₆H₆ * 78 g/mol = 53.04 g C₆H₆.
Therefore, approximately 53 grams of C₆H₆ must decompose to transfer 430 kJ of heat.