ZnO + K2O = K2ZnO2

ZnO zinc oxide + K_2O potassium oxide ⟶ K2ZnO2

Balance the chemical equation algebraically: ZnO + K_2O ⟶ K2ZnO2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 ZnO + c_2 K_2O ⟶ c_3 K2ZnO2 Set the number of atoms in the reactants equal to the number of atoms in the products for O, Zn and K: O: | c_1 + c_2 = 2 c_3 Zn: | c_1 = c_3 K: | 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | ZnO + K_2O ⟶ K2ZnO2

+ ⟶ K2ZnO2

zinc oxide + potassium oxide ⟶ K2ZnO2

Construct the equilibrium constant, K, expression for: ZnO + K_2O ⟶ K2ZnO2 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 + K_2O ⟶ K2ZnO2 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 K_2O | 1 | -1 K2ZnO2 | 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) K_2O | 1 | -1 | ([K2O])^(-1) K2ZnO2 | 1 | 1 | [K2ZnO2] 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) ([K2O])^(-1) [K2ZnO2] = ([K2ZnO2])/([ZnO] [K2O])

Construct the rate of reaction expression for: ZnO + K_2O ⟶ K2ZnO2 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 + K_2O ⟶ K2ZnO2 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 K_2O | 1 | -1 K2ZnO2 | 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) K_2O | 1 | -1 | -(Δ[K2O])/(Δt) K2ZnO2 | 1 | 1 | (Δ[K2ZnO2])/(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[K2O])/(Δt) = (Δ[K2ZnO2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc oxide | potassium oxide | K2ZnO2 formula | ZnO | K_2O | K2ZnO2 Hill formula | OZn | K_2O | K2O2Zn name | zinc oxide | potassium oxide | IUPAC name | oxozinc | dipotassium oxygen(2-) |

| zinc oxide | potassium oxide | K2ZnO2 molar mass | 81.38 g/mol | 94.196 g/mol | 175.6 g/mol phase | solid (at STP) | | melting point | 1975 °C | | boiling point | 2360 °C | | density | 5.6 g/cm^3 | | odor | odorless | |