HgSFe = FeSHg

HgSFe ⟶ FeSHg

Balance the chemical equation algebraically: HgSFe ⟶ FeSHg Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HgSFe ⟶ c_2 FeSHg Set the number of atoms in the reactants equal to the number of atoms in the products for Hg, S and Fe: Hg: | c_1 = c_2 S: | c_1 = c_2 Fe: | c_1 = c_2 Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | HgSFe ⟶ FeSHg

HgSFe ⟶ FeSHg

HgSFe ⟶ FeSHg

Construct the equilibrium constant, K, expression for: HgSFe ⟶ FeSHg Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the activity expression for each chemical species. • Use the activity expressions to build the equilibrium constant expression. Write the balanced chemical equation: HgSFe ⟶ FeSHg Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i HgSFe | 1 | -1 FeSHg | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HgSFe | 1 | -1 | ([HgSFe])^(-1) FeSHg | 1 | 1 | [FeSHg] The equilibrium constant symbol in the concentration basis is: K_c Mulitply the activity expressions to arrive at the K_c expression: Answer: | | K_c = ([HgSFe])^(-1) [FeSHg] = ([FeSHg])/([HgSFe])

Construct the rate of reaction expression for: HgSFe ⟶ FeSHg Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the rate term for each chemical species. • Write the rate of reaction expression. Write the balanced chemical equation: HgSFe ⟶ FeSHg Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i HgSFe | 1 | -1 FeSHg | 1 | 1 The rate term for each chemical species, B_i, is 1/ν_i(Δ[B_i])/(Δt) where [B_i] is the amount concentration and t is time: chemical species | c_i | ν_i | rate term HgSFe | 1 | -1 | -(Δ[HgSFe])/(Δt) FeSHg | 1 | 1 | (Δ[FeSHg])/(Δt) (for infinitesimal rate of change, replace Δ with d) Set the rate terms equal to each other to arrive at the rate expression: Answer: | | rate = -(Δ[HgSFe])/(Δt) = (Δ[FeSHg])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| HgSFe | FeSHg formula | HgSFe | FeSHg Hill formula | FeHgS | FeHgS

| HgSFe | FeSHg molar mass | 288.5 g/mol | 288.5 g/mol