NaOH + ZnO = Na2O + Zn(OH)2

NaOH (sodium hydroxide) + ZnO (zinc oxide) ⟶ Na_2O (sodium oxide) + Zn(OH)_2 (zinc hydroxide)

Balance the chemical equation algebraically: NaOH + ZnO ⟶ Na_2O + Zn(OH)_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaOH + c_2 ZnO ⟶ c_3 Na_2O + c_4 Zn(OH)_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O and Zn: H: | c_1 = 2 c_4 Na: | c_1 = 2 c_3 O: | c_1 + c_2 = c_3 + 2 c_4 Zn: | c_2 = 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 NaOH + ZnO ⟶ Na_2O + Zn(OH)_2

+ ⟶ +

sodium hydroxide + zinc oxide ⟶ sodium oxide + zinc hydroxide

Construct the equilibrium constant, K, expression for: NaOH + ZnO ⟶ Na_2O + Zn(OH)_2 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: 2 NaOH + ZnO ⟶ Na_2O + Zn(OH)_2 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 NaOH | 2 | -2 ZnO | 1 | -1 Na_2O | 1 | 1 Zn(OH)_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaOH | 2 | -2 | ([NaOH])^(-2) ZnO | 1 | -1 | ([ZnO])^(-1) Na_2O | 1 | 1 | [Na2O] Zn(OH)_2 | 1 | 1 | [Zn(OH)2] 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 = ([NaOH])^(-2) ([ZnO])^(-1) [Na2O] [Zn(OH)2] = ([Na2O] [Zn(OH)2])/(([NaOH])^2 [ZnO])

Construct the rate of reaction expression for: NaOH + ZnO ⟶ Na_2O + Zn(OH)_2 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: 2 NaOH + ZnO ⟶ Na_2O + Zn(OH)_2 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 NaOH | 2 | -2 ZnO | 1 | -1 Na_2O | 1 | 1 Zn(OH)_2 | 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 NaOH | 2 | -2 | -1/2 (Δ[NaOH])/(Δt) ZnO | 1 | -1 | -(Δ[ZnO])/(Δt) Na_2O | 1 | 1 | (Δ[Na2O])/(Δt) Zn(OH)_2 | 1 | 1 | (Δ[Zn(OH)2])/(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 = -1/2 (Δ[NaOH])/(Δt) = -(Δ[ZnO])/(Δt) = (Δ[Na2O])/(Δt) = (Δ[Zn(OH)2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium hydroxide | zinc oxide | sodium oxide | zinc hydroxide formula | NaOH | ZnO | Na_2O | Zn(OH)_2 Hill formula | HNaO | OZn | Na_2O | H_2O_2Zn name | sodium hydroxide | zinc oxide | sodium oxide | zinc hydroxide IUPAC name | sodium hydroxide | oxozinc | disodium oxygen(-2) anion | zinc dihydroxide

| sodium hydroxide | zinc oxide | sodium oxide | zinc hydroxide molar mass | 39.997 g/mol | 81.38 g/mol | 61.979 g/mol | 99.39 g/mol phase | solid (at STP) | solid (at STP) | | melting point | 323 °C | 1975 °C | | boiling point | 1390 °C | 2360 °C | | density | 2.13 g/cm^3 | 5.6 g/cm^3 | 2.27 g/cm^3 | solubility in water | soluble | | | surface tension | 0.07435 N/m | | | dynamic viscosity | 0.004 Pa s (at 350 °C) | | | odor | | odorless | |