H2SO4 + H2O2 + NiS = H2O + S + NiSO4

H_2SO_4 sulfuric acid + H_2O_2 hydrogen peroxide + SNi nickel(II) sulfide ⟶ H_2O water + S mixed sulfur + NiSO_4 nickel(II) sulfate

Balance the chemical equation algebraically: H_2SO_4 + H_2O_2 + SNi ⟶ H_2O + S + NiSO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 H_2O_2 + c_3 SNi ⟶ c_4 H_2O + c_5 S + c_6 NiSO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S and Ni: H: | 2 c_1 + 2 c_2 = 2 c_4 O: | 4 c_1 + 2 c_2 = c_4 + 4 c_6 S: | c_1 + c_3 = c_5 + c_6 Ni: | c_3 = c_6 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_3 = c_2/4 + 3/4 c_4 = c_2 + 1 c_5 = 1 c_6 = c_2/4 + 3/4 The resulting system of equations is still underdetermined, so an additional coefficient must be set arbitrarily. Set c_2 = 1 and solve for the remaining coefficients: c_1 = 1 c_2 = 1 c_3 = 1 c_4 = 2 c_5 = 1 c_6 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2SO_4 + H_2O_2 + SNi ⟶ 2 H_2O + S + NiSO_4

+ + ⟶ + +

sulfuric acid + hydrogen peroxide + nickel(II) sulfide ⟶ water + mixed sulfur + nickel(II) sulfate

Construct the equilibrium constant, K, expression for: H_2SO_4 + H_2O_2 + SNi ⟶ H_2O + S + NiSO_4 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: H_2SO_4 + H_2O_2 + SNi ⟶ 2 H_2O + S + NiSO_4 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 H_2SO_4 | 1 | -1 H_2O_2 | 1 | -1 SNi | 1 | -1 H_2O | 2 | 2 S | 1 | 1 NiSO_4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2SO_4 | 1 | -1 | ([H2SO4])^(-1) H_2O_2 | 1 | -1 | ([H2O2])^(-1) SNi | 1 | -1 | ([S1Ni1])^(-1) H_2O | 2 | 2 | ([H2O])^2 S | 1 | 1 | [S] NiSO_4 | 1 | 1 | [NiSO4] 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 = ([H2SO4])^(-1) ([H2O2])^(-1) ([S1Ni1])^(-1) ([H2O])^2 [S] [NiSO4] = (([H2O])^2 [S] [NiSO4])/([H2SO4] [H2O2] [S1Ni1])

Construct the rate of reaction expression for: H_2SO_4 + H_2O_2 + SNi ⟶ H_2O + S + NiSO_4 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: H_2SO_4 + H_2O_2 + SNi ⟶ 2 H_2O + S + NiSO_4 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 H_2SO_4 | 1 | -1 H_2O_2 | 1 | -1 SNi | 1 | -1 H_2O | 2 | 2 S | 1 | 1 NiSO_4 | 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 H_2SO_4 | 1 | -1 | -(Δ[H2SO4])/(Δt) H_2O_2 | 1 | -1 | -(Δ[H2O2])/(Δt) SNi | 1 | -1 | -(Δ[S1Ni1])/(Δt) H_2O | 2 | 2 | 1/2 (Δ[H2O])/(Δt) S | 1 | 1 | (Δ[S])/(Δt) NiSO_4 | 1 | 1 | (Δ[NiSO4])/(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[H2SO4])/(Δt) = -(Δ[H2O2])/(Δt) = -(Δ[S1Ni1])/(Δt) = 1/2 (Δ[H2O])/(Δt) = (Δ[S])/(Δt) = (Δ[NiSO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | hydrogen peroxide | nickel(II) sulfide | water | mixed sulfur | nickel(II) sulfate formula | H_2SO_4 | H_2O_2 | SNi | H_2O | S | NiSO_4 Hill formula | H_2O_4S | H_2O_2 | NiS | H_2O | S | NiO_4S name | sulfuric acid | hydrogen peroxide | nickel(II) sulfide | water | mixed sulfur | nickel(II) sulfate IUPAC name | sulfuric acid | hydrogen peroxide | sulfanylidenenickel | water | sulfur | nickelous sulfate

| sulfuric acid | hydrogen peroxide | nickel(II) sulfide | water | mixed sulfur | nickel(II) sulfate molar mass | 98.07 g/mol | 34.014 g/mol | 90.75 g/mol | 18.015 g/mol | 32.06 g/mol | 154.75 g/mol phase | liquid (at STP) | liquid (at STP) | | liquid (at STP) | solid (at STP) | solid (at STP) melting point | 10.371 °C | -0.43 °C | | 0 °C | 112.8 °C | boiling point | 279.6 °C | 150.2 °C | | 99.9839 °C | 444.7 °C | density | 1.8305 g/cm^3 | 1.44 g/cm^3 | | 1 g/cm^3 | 2.07 g/cm^3 | 4.01 g/cm^3 solubility in water | very soluble | miscible | | | | surface tension | 0.0735 N/m | 0.0804 N/m | | 0.0728 N/m | | dynamic viscosity | 0.021 Pa s (at 25 °C) | 0.001249 Pa s (at 20 °C) | | 8.9×10^-4 Pa s (at 25 °C) | | odor | odorless | | | odorless | |