Consider the reaction 2 SO2( g)+O2( g) ⟶2 SO3( g) (a) Calculate ΔG^∘ at 25^∘ C. (b) If the parti

step 1 on with our thermodynamics work and again we're looking at the calculation for the standard free

Consider the reaction 2 SO2( g)+O2( g) ⟶2 SO3( g) (a)...

Consider the reaction $$ 2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{SO}_3(\mathrm{~g}) $$ (a) Calculate $\Delta G^{\circ}$ at $25^{\circ} \mathrm{C}$. (b) If the partial pressures of $\mathrm{SO}_2$ and $\mathrm{SO}_3$ are kept at 0.400 atm , what partial pressure should $\mathrm{O}_2$ have so that the reaction just becomes nonspontancous (i.c., $\Delta G=+1.0 \mathrm{~kJ}$ )?

Consider the reaction

$$
2 \mathrm{SO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \longrightarrow 2 \mathrm{SO}_3(\mathrm{~g})
$$

(a) Calculate $\Delta G^{\circ}$ at $25^{\circ} \mathrm{C}$.
(b) If the partial pressures of $\mathrm{SO}_2$ and $\mathrm{SO}_3$ are kept at 0.400 atm , what partial pressure should $\mathrm{O}_2$ have so that the reaction just becomes nonspontancous (i.c., $\Delta G=+1.0 \mathrm{~kJ}$ )?

Key Concepts

Reaction Quotient (Q)

The reaction quotient is a dimensionless number that expresses the ratio of the concentrations (or partial pressures) of the products to those of the reactants at any point in time, each raised to the power of their stoichiometric coefficients. It is used to determine the direction in which a reaction will proceed to reach equilibrium.

Non-standard Free Energy Change

The free energy change of a reaction under non-standard conditions is calculated using the relation ?G = ?G° + RT ln Q, where R is the gas constant, T is the temperature in Kelvin, and Q is the reaction quotient. This equation adjusts the standard free energy change to account for actual conditions of reactants and products.

Gibbs Free Energy

This concept refers to the thermodynamic potential that can be used to predict the spontaneity of a chemical reaction at constant temperature and pressure. It helps determine whether a reaction will proceed without external work by comparing the system’s free energy change under set conditions.

Standard State Conditions

Standard state conditions define a set of agreed-upon states (typically 1 atm for gases, 1 M for solutions, at a specific temperature such as 25°C) that serve as a reference for thermodynamic data such as standard Gibbs free energy changes (?G°). These conditions allow for consistent calculation and comparison of thermodynamic values.

Thermodynamic Equilibrium

At equilibrium, the free energy of the system is minimized, and there is no net change in the composition of reactants and products. The condition for equilibrium is met when ?G equals zero (or is set to a specific threshold for non-spontaneity), which then determines the necessary conditions such as the partial pressures for gases in the reaction.

Transcript

Please give Ace some feedback