Zn + H2SO3 = H2 + ZnSO3

Zn zinc + H_2SO_3 sulfurous acid ⟶ H_2 hydrogen + ZnSO3

Balance the chemical equation algebraically: Zn + H_2SO_3 ⟶ H_2 + ZnSO3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Zn + c_2 H_2SO_3 ⟶ c_3 H_2 + c_4 ZnSO3 Set the number of atoms in the reactants equal to the number of atoms in the products for Zn, H, O and S: Zn: | c_1 = c_4 H: | 2 c_2 = 2 c_3 O: | 3 c_2 = 3 c_4 S: | 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_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_2SO_3 ⟶ H_2 + ZnSO3

+ ⟶ + ZnSO3

zinc + sulfurous acid ⟶ hydrogen + ZnSO3

Construct the equilibrium constant, K, expression for: Zn + H_2SO_3 ⟶ H_2 + ZnSO3 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_2SO_3 ⟶ H_2 + ZnSO3 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_2SO_3 | 1 | -1 H_2 | 1 | 1 ZnSO3 | 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_2SO_3 | 1 | -1 | ([H2SO3])^(-1) H_2 | 1 | 1 | [H2] ZnSO3 | 1 | 1 | [ZnSO3] 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) ([H2SO3])^(-1) [H2] [ZnSO3] = ([H2] [ZnSO3])/([Zn] [H2SO3])

Construct the rate of reaction expression for: Zn + H_2SO_3 ⟶ H_2 + ZnSO3 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_2SO_3 ⟶ H_2 + ZnSO3 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_2SO_3 | 1 | -1 H_2 | 1 | 1 ZnSO3 | 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_2SO_3 | 1 | -1 | -(Δ[H2SO3])/(Δt) H_2 | 1 | 1 | (Δ[H2])/(Δt) ZnSO3 | 1 | 1 | (Δ[ZnSO3])/(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[H2SO3])/(Δt) = (Δ[H2])/(Δt) = (Δ[ZnSO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc | sulfurous acid | hydrogen | ZnSO3 formula | Zn | H_2SO_3 | H_2 | ZnSO3 Hill formula | Zn | H_2O_3S | H_2 | O3SZn name | zinc | sulfurous acid | hydrogen | IUPAC name | zinc | sulfurous acid | molecular hydrogen |

| zinc | sulfurous acid | hydrogen | ZnSO3 molar mass | 65.38 g/mol | 82.07 g/mol | 2.016 g/mol | 145.4 g/mol phase | solid (at STP) | | gas (at STP) | melting point | 420 °C | | -259.2 °C | boiling point | 907 °C | | -252.8 °C | density | 7.14 g/cm^3 | 1.03 g/cm^3 | 8.99×10^-5 g/cm^3 (at 0 °C) | solubility in water | insoluble | very soluble | | dynamic viscosity | | | 8.9×10^-6 Pa s (at 25 °C) | odor | odorless | | odorless |