Zn + H2O2 = H2O + ZnO

Zn zinc + H_2O_2 hydrogen peroxide ⟶ H_2O water + ZnO zinc oxide

Balance the chemical equation algebraically: Zn + H_2O_2 ⟶ H_2O + ZnO Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Zn + c_2 H_2O_2 ⟶ c_3 H_2O + c_4 ZnO Set the number of atoms in the reactants equal to the number of atoms in the products for Zn, H and O: Zn: | c_1 = c_4 H: | 2 c_2 = 2 c_3 O: | 2 c_2 = c_3 + 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: | | Zn + H_2O_2 ⟶ H_2O + ZnO

+ ⟶ +

zinc + hydrogen peroxide ⟶ water + zinc oxide

Construct the equilibrium constant, K, expression for: Zn + H_2O_2 ⟶ H_2O + ZnO 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: Zn + H_2O_2 ⟶ H_2O + ZnO 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 Zn | 1 | -1 H_2O_2 | 1 | -1 H_2O | 1 | 1 ZnO | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Zn | 1 | -1 | ([Zn])^(-1) H_2O_2 | 1 | -1 | ([H2O2])^(-1) H_2O | 1 | 1 | [H2O] ZnO | 1 | 1 | [ZnO] 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 = ([Zn])^(-1) ([H2O2])^(-1) [H2O] [ZnO] = ([H2O] [ZnO])/([Zn] [H2O2])

Construct the rate of reaction expression for: Zn + H_2O_2 ⟶ H_2O + ZnO 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: Zn + H_2O_2 ⟶ H_2O + ZnO 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 Zn | 1 | -1 H_2O_2 | 1 | -1 H_2O | 1 | 1 ZnO | 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 Zn | 1 | -1 | -(Δ[Zn])/(Δt) H_2O_2 | 1 | -1 | -(Δ[H2O2])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) ZnO | 1 | 1 | (Δ[ZnO])/(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[Zn])/(Δt) = -(Δ[H2O2])/(Δt) = (Δ[H2O])/(Δt) = (Δ[ZnO])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc | hydrogen peroxide | water | zinc oxide formula | Zn | H_2O_2 | H_2O | ZnO Hill formula | Zn | H_2O_2 | H_2O | OZn name | zinc | hydrogen peroxide | water | zinc oxide IUPAC name | zinc | hydrogen peroxide | water | oxozinc

| zinc | hydrogen peroxide | water | zinc oxide molar mass | 65.38 g/mol | 34.014 g/mol | 18.015 g/mol | 81.38 g/mol phase | solid (at STP) | liquid (at STP) | liquid (at STP) | solid (at STP) melting point | 420 °C | -0.43 °C | 0 °C | 1975 °C boiling point | 907 °C | 150.2 °C | 99.9839 °C | 2360 °C density | 7.14 g/cm^3 | 1.44 g/cm^3 | 1 g/cm^3 | 5.6 g/cm^3 solubility in water | insoluble | miscible | | surface tension | | 0.0804 N/m | 0.0728 N/m | dynamic viscosity | | 0.001249 Pa s (at 20 °C) | 8.9×10^-4 Pa s (at 25 °C) | odor | odorless | | odorless | odorless