FeSO4 + KCN = K2SO4 + K4Fe(CN)6

FeSO_4 duretter + KCN potassium cyanide ⟶ K_2SO_4 potassium sulfate + K4Fe(CN)6

Balance the chemical equation algebraically: FeSO_4 + KCN ⟶ K_2SO_4 + K4Fe(CN)6 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 FeSO_4 + c_2 KCN ⟶ c_3 K_2SO_4 + c_4 K4Fe(CN)6 Set the number of atoms in the reactants equal to the number of atoms in the products for Fe, O, S, C, K and N: Fe: | c_1 = c_4 O: | 4 c_1 = 4 c_3 S: | c_1 = c_3 C: | c_2 = 6 c_4 K: | c_2 = 2 c_3 + 4 c_4 N: | c_2 = 6 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 = 6 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | FeSO_4 + 6 KCN ⟶ K_2SO_4 + K4Fe(CN)6

+ ⟶ + K4Fe(CN)6

duretter + potassium cyanide ⟶ potassium sulfate + K4Fe(CN)6

Construct the equilibrium constant, K, expression for: FeSO_4 + KCN ⟶ K_2SO_4 + K4Fe(CN)6 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: FeSO_4 + 6 KCN ⟶ K_2SO_4 + K4Fe(CN)6 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 FeSO_4 | 1 | -1 KCN | 6 | -6 K_2SO_4 | 1 | 1 K4Fe(CN)6 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression FeSO_4 | 1 | -1 | ([FeSO4])^(-1) KCN | 6 | -6 | ([KCN])^(-6) K_2SO_4 | 1 | 1 | [K2SO4] K4Fe(CN)6 | 1 | 1 | [K4Fe(CN)6] 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 = ([FeSO4])^(-1) ([KCN])^(-6) [K2SO4] [K4Fe(CN)6] = ([K2SO4] [K4Fe(CN)6])/([FeSO4] ([KCN])^6)

Construct the rate of reaction expression for: FeSO_4 + KCN ⟶ K_2SO_4 + K4Fe(CN)6 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: FeSO_4 + 6 KCN ⟶ K_2SO_4 + K4Fe(CN)6 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 FeSO_4 | 1 | -1 KCN | 6 | -6 K_2SO_4 | 1 | 1 K4Fe(CN)6 | 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 FeSO_4 | 1 | -1 | -(Δ[FeSO4])/(Δt) KCN | 6 | -6 | -1/6 (Δ[KCN])/(Δt) K_2SO_4 | 1 | 1 | (Δ[K2SO4])/(Δt) K4Fe(CN)6 | 1 | 1 | (Δ[K4Fe(CN)6])/(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[FeSO4])/(Δt) = -1/6 (Δ[KCN])/(Δt) = (Δ[K2SO4])/(Δt) = (Δ[K4Fe(CN)6])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| duretter | potassium cyanide | potassium sulfate | K4Fe(CN)6 formula | FeSO_4 | KCN | K_2SO_4 | K4Fe(CN)6 Hill formula | FeO_4S | CKN | K_2O_4S | C6FeK4N6 name | duretter | potassium cyanide | potassium sulfate | IUPAC name | iron(+2) cation sulfate | potassium cyanide | dipotassium sulfate |

| duretter | potassium cyanide | potassium sulfate | K4Fe(CN)6 molar mass | 151.9 g/mol | 65.116 g/mol | 174.25 g/mol | 368.35 g/mol density | 2.841 g/cm^3 | | | solubility in water | | | soluble |