Final answer:
The value of ΔH° for the reaction 2A + 3B → 4C, given the enthalpy change per mole of C as −450 kJ/mol is calculated to be −1800 kJ by multiplying the stoichiometric coefficient of C (4) by the provided enthalpy change per mole C.
Step-by-step explanation:
To calculate the value of ΔH° for the reaction 2A + 3B → 4C, when given ΔH° = −450 kJ mol−¹, we can use stoichiometry and the principles of enthalpy change. Since the reaction is given in terms of moles, we need to account for the stoichiometric coefficients to find the total enthalpy change for the reaction.
According to the stoichiometry of the reaction, for every 2 moles of A and 3 moles of B reacting, 4 moles of C are produced. Therefore, if we have ΔH° for the production of C as −450 kJ/mol, we need to multiply this by the stoichiometric coefficient of C in the balanced equation, which is 4:
ΔH°(total) = 4 mol C × (−450 kJ mol−¹ C) = −1800 kJ
Therefore, the total standard enthalpy change for the reaction (ΔH°) is −1800 kilojoules.