Question

Determine ΔG for the following reactions.

(a) Antimony pentachloride decomposes at 448 °C. The reaction is:


SbCl₅ (g)?SbCl₃(g) + Cl₂(g)


An equilibrium mixture in a 5.00 L flask at 448 °C contains 3.85 g of SbCl5, 9.14 g of SbCl3, and 2.84 g of Cl2.


(b) Chlorine molecules dissociate according to this reaction:


Cl₂(g) ? 2Cl(g)


1.00% of Cl₂ molecules dissociate at 975 K and a pressure of 1.00 atm.

Answer 1

To determine ΔG for the decomposition of antimony pentachloride and the dissociation of chlorine molecules, we can use the equations ΔG = ΔG° + RT ln(Q) and ΔG = -RT ln(K) respectively.

Step-by-step explanation:

(a) To determine the standard free energy change, ΔG, for the decomposition of antimony pentachloride at 448 °C, we need to use the equation:

ΔG = ΔG° + RT ln(Q)

where ΔG° is the standard free energy change, R is the gas constant, T is the temperature in Kelvin, and Q is the reaction quotient. Given the initial concentrations of SbCl₅, SbCl₃, and Cl₂ in the 5.00 L flask, we can calculate the values using their molar masses and stoichiometry of the reaction.

(b) To determine the standard free energy change, ΔG, for the dissociation of chlorine molecules, we need to use the equation:

ΔG = -RT ln(K)

where R is the gas constant, T is the temperature in Kelvin, and K is the equilibrium constant. Given that 1.00% of Cl₂ molecules dissociate at 975 K and a pressure of 1.00 atm, we can calculate the equilibrium constant K and then calculate ΔG using the equation.