For the reaction 2NO(g) + O₂(g) $\rarr$ 2NO₂(g) if initially P(NO) = 1.5 atm, P(O₂) = 1.4 atm, and P(NO₂) = 2.0 atm, calculate $\Delta$G for this reaction at 25^$\circ$C. The following data is valid at 25^$\circ$C: $\begin{array}{|c|c|} \hline & \Delta \mathrm{G}_{\mathrm{f}}{ }^{\circ}(\mathrm{kJ} / \mathrm{mol}) \ \hline \mathrm{NO} & 86.7 \ \hline \mathrm{NO}_{2} & 51.8 \ \hline \end{array}$ A) -69.9 kJ/mol B) -69.2 kJ/mol C) 522.1 kJ/mol D) -79.9 kJ/mol E) -35.0 kJ/mol

Question

Quizplus · Accepted Answer

The first step is to write out the balanced chemical equation and determine the stoichiometric coefficients.

2NO(g) + O2(g) -> 2NO2(g)

From the initial pressures, we can calculate the partial pressures of each gas at equilibrium using the following equation:

Kp = (PN02)^2 / (PNO)^2 (PO2)

Using the given data, we get:

Kp = (2.0)^2 / (1.5)^2 (1.4) = 1.84

Next, we use the formula:

ΔG = -RT ln Kp

where R is the gas constant (8.314 J/mol•K) and T is the temperature (25°C = 298 K).

ΔG = -(8.314 J/mol•K) (298 K) ln (1.84)

ΔG = -69.2 kJ/mol

Therefore, the best choice is B, with an explanation as provided above.

For the Reaction 2NO(g) + O2(g) →\rarr→ 2NO2(g) If Initially P(NO) = 1

For the Reaction 2NO(g) + O₂(g) $\rarr$ 2NO₂(g) If Initially P(NO) = 1