ZnSO4 + Na2S = Na2SO4 + ZnS

ZnSO_4 zinc sulfate + Na_2S sodium sulfide ⟶ Na_2SO_4 sodium sulfate + ZnS zinc sulfide

Balance the chemical equation algebraically: ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS Add stoichiometric coefficients, c_i, to the reactants and products: c_1 ZnSO_4 + c_2 Na_2S ⟶ c_3 Na_2SO_4 + c_4 ZnS Set the number of atoms in the reactants equal to the number of atoms in the products for O, S, Zn and Na: O: | 4 c_1 = 4 c_3 S: | c_1 + c_2 = c_3 + c_4 Zn: | c_1 = c_4 Na: | 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: | | ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS

+ ⟶ +

zinc sulfate + sodium sulfide ⟶ sodium sulfate + zinc sulfide

Construct the equilibrium constant, K, expression for: ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS 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: ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS 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 ZnSO_4 | 1 | -1 Na_2S | 1 | -1 Na_2SO_4 | 1 | 1 ZnS | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression ZnSO_4 | 1 | -1 | ([ZnSO4])^(-1) Na_2S | 1 | -1 | ([Na2S])^(-1) Na_2SO_4 | 1 | 1 | [Na2SO4] ZnS | 1 | 1 | [ZnS] 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 = ([ZnSO4])^(-1) ([Na2S])^(-1) [Na2SO4] [ZnS] = ([Na2SO4] [ZnS])/([ZnSO4] [Na2S])

Construct the rate of reaction expression for: ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS 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: ZnSO_4 + Na_2S ⟶ Na_2SO_4 + ZnS 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 ZnSO_4 | 1 | -1 Na_2S | 1 | -1 Na_2SO_4 | 1 | 1 ZnS | 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 ZnSO_4 | 1 | -1 | -(Δ[ZnSO4])/(Δt) Na_2S | 1 | -1 | -(Δ[Na2S])/(Δt) Na_2SO_4 | 1 | 1 | (Δ[Na2SO4])/(Δt) ZnS | 1 | 1 | (Δ[ZnS])/(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[ZnSO4])/(Δt) = -(Δ[Na2S])/(Δt) = (Δ[Na2SO4])/(Δt) = (Δ[ZnS])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc sulfate | sodium sulfide | sodium sulfate | zinc sulfide formula | ZnSO_4 | Na_2S | Na_2SO_4 | ZnS Hill formula | O_4SZn | Na_2S_1 | Na_2O_4S | SZn name | zinc sulfate | sodium sulfide | sodium sulfate | zinc sulfide IUPAC name | zinc sulfate | | disodium sulfate | thioxozinc

| zinc sulfate | sodium sulfide | sodium sulfate | zinc sulfide molar mass | 161.4 g/mol | 78.04 g/mol | 142.04 g/mol | 97.44 g/mol phase | | solid (at STP) | solid (at STP) | solid (at STP) melting point | | 1172 °C | 884 °C | 1064 °C boiling point | | | 1429 °C | density | 1.005 g/cm^3 | 1.856 g/cm^3 | 2.68 g/cm^3 | 4.1 g/cm^3 solubility in water | soluble | | soluble | odor | odorless | | |