ZnO + Fe(OH)2 = H2O + ZnFeO2

ZnO zinc oxide + Fe(OH)_2 iron(II) hydroxide ⟶ H_2O water + ZnFeO2

Balance the chemical equation algebraically: ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 ZnO + c_2 Fe(OH)_2 ⟶ c_3 H_2O + c_4 ZnFeO2 Set the number of atoms in the reactants equal to the number of atoms in the products for O, Zn, Fe and H: O: | c_1 + 2 c_2 = c_3 + 2 c_4 Zn: | c_1 = c_4 Fe: | c_2 = c_4 H: | 2 c_2 = 2 c_3 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: | | ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2

+ ⟶ + ZnFeO2

zinc oxide + iron(II) hydroxide ⟶ water + ZnFeO2

Construct the equilibrium constant, K, expression for: ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2 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: ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2 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 ZnO | 1 | -1 Fe(OH)_2 | 1 | -1 H_2O | 1 | 1 ZnFeO2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression ZnO | 1 | -1 | ([ZnO])^(-1) Fe(OH)_2 | 1 | -1 | ([Fe(OH)2])^(-1) H_2O | 1 | 1 | [H2O] ZnFeO2 | 1 | 1 | [ZnFeO2] 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 = ([ZnO])^(-1) ([Fe(OH)2])^(-1) [H2O] [ZnFeO2] = ([H2O] [ZnFeO2])/([ZnO] [Fe(OH)2])

Construct the rate of reaction expression for: ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2 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: ZnO + Fe(OH)_2 ⟶ H_2O + ZnFeO2 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 ZnO | 1 | -1 Fe(OH)_2 | 1 | -1 H_2O | 1 | 1 ZnFeO2 | 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 ZnO | 1 | -1 | -(Δ[ZnO])/(Δt) Fe(OH)_2 | 1 | -1 | -(Δ[Fe(OH)2])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) ZnFeO2 | 1 | 1 | (Δ[ZnFeO2])/(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[ZnO])/(Δt) = -(Δ[Fe(OH)2])/(Δt) = (Δ[H2O])/(Δt) = (Δ[ZnFeO2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc oxide | iron(II) hydroxide | water | ZnFeO2 formula | ZnO | Fe(OH)_2 | H_2O | ZnFeO2 Hill formula | OZn | FeH_2O_2 | H_2O | FeO2Zn name | zinc oxide | iron(II) hydroxide | water | IUPAC name | oxozinc | ferrous dihydroxide | water |

| zinc oxide | iron(II) hydroxide | water | ZnFeO2 molar mass | 81.38 g/mol | 89.86 g/mol | 18.015 g/mol | 153.2 g/mol phase | solid (at STP) | | liquid (at STP) | melting point | 1975 °C | | 0 °C | boiling point | 2360 °C | | 99.9839 °C | density | 5.6 g/cm^3 | | 1 g/cm^3 | surface tension | | | 0.0728 N/m | dynamic viscosity | | | 8.9×10^-4 Pa s (at 25 °C) | odor | odorless | | odorless |