Fe + CuS4 = Cu + FeS4

Fe iron + CuS4 ⟶ Cu copper + FeS4

Balance the chemical equation algebraically: Fe + CuS4 ⟶ Cu + FeS4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Fe + c_2 CuS4 ⟶ c_3 Cu + c_4 FeS4 Set the number of atoms in the reactants equal to the number of atoms in the products for Fe, Cu and S: Fe: | c_1 = c_4 Cu: | c_2 = c_3 S: | 4 c_2 = 4 c_4 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 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Fe + CuS4 ⟶ Cu + FeS4

+ CuS4 ⟶ + FeS4

iron + CuS4 ⟶ copper + FeS4

Construct the equilibrium constant, K, expression for: Fe + CuS4 ⟶ Cu + FeS4 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: Fe + CuS4 ⟶ Cu + FeS4 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 Fe | 1 | -1 CuS4 | 1 | -1 Cu | 1 | 1 FeS4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Fe | 1 | -1 | ([Fe])^(-1) CuS4 | 1 | -1 | ([CuS4])^(-1) Cu | 1 | 1 | [Cu] FeS4 | 1 | 1 | [FeS4] 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 = ([Fe])^(-1) ([CuS4])^(-1) [Cu] [FeS4] = ([Cu] [FeS4])/([Fe] [CuS4])

Construct the rate of reaction expression for: Fe + CuS4 ⟶ Cu + FeS4 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: Fe + CuS4 ⟶ Cu + FeS4 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 Fe | 1 | -1 CuS4 | 1 | -1 Cu | 1 | 1 FeS4 | 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 Fe | 1 | -1 | -(Δ[Fe])/(Δt) CuS4 | 1 | -1 | -(Δ[CuS4])/(Δt) Cu | 1 | 1 | (Δ[Cu])/(Δt) FeS4 | 1 | 1 | (Δ[FeS4])/(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[Fe])/(Δt) = -(Δ[CuS4])/(Δt) = (Δ[Cu])/(Δt) = (Δ[FeS4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| iron | CuS4 | copper | FeS4 formula | Fe | CuS4 | Cu | FeS4 name | iron | | copper |

| iron | CuS4 | copper | FeS4 molar mass | 55.845 g/mol | 191.8 g/mol | 63.546 g/mol | 184.1 g/mol phase | solid (at STP) | | solid (at STP) | melting point | 1535 °C | | 1083 °C | boiling point | 2750 °C | | 2567 °C | density | 7.874 g/cm^3 | | 8.96 g/cm^3 | solubility in water | insoluble | | insoluble | odor | | | odorless |