Question

fill in the missing words
use a thermochemical reaction of the reaction below to fill in the blanks:
2 ab(g) + d₂(g) → 2 ad(g) + c₂(g) δh = -420 kj/mol
a) when two moles of ab react with one mole of d₂ kj of energy are released as heat. when one mole of ab reacts with 0.5 mole of d₂ kj of energy is released as heat.
b) for the reverse reaction (2 ad(g) + c₂(g) → 2 ab(g) + d₂(g)) the change of enthalpy is kj/mol.

Explanation:

Step1: Analyze given reaction enthalpy

The given reaction $2AB(g)+D_2(g)\to2AD(g)+C_2(g)$ has $\Delta H = - 420\ kJ/mol$. A negative $\Delta H$ means heat is released. When the amounts of reactants match the stoichiometric coefficients (2 moles of $AB$ and 1 mole of $D_2$), the heat released is equal to the magnitude of $\Delta H$.

Step2: Calculate heat release for half - amount of reactants

If we have half the amounts of reactants (1 mole of $AB$ and 0.5 mole of $D_2$) compared to the given reaction, the heat released will also be half of the original $\Delta H$ value.

Step3: Determine $\Delta H$ for reverse reaction

For a reverse reaction, the sign of $\Delta H$ changes.

Answer:

a) 420; 210
b) 420