Cl2 + H2S = HCl + SCl4

Cl_2 chlorine + H_2S hydrogen sulfide ⟶ HCl hydrogen chloride + SCl4

Balance the chemical equation algebraically: Cl_2 + H_2S ⟶ HCl + SCl4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 H_2S ⟶ c_3 HCl + c_4 SCl4 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and S: Cl: | 2 c_1 = c_3 + 4 c_4 H: | 2 c_2 = c_3 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3 c_2 = 1 c_3 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 Cl_2 + H_2S ⟶ 2 HCl + SCl4

+ ⟶ + SCl4

chlorine + hydrogen sulfide ⟶ hydrogen chloride + SCl4

Construct the equilibrium constant, K, expression for: Cl_2 + H_2S ⟶ HCl + SCl4 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: 3 Cl_2 + H_2S ⟶ 2 HCl + SCl4 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 Cl_2 | 3 | -3 H_2S | 1 | -1 HCl | 2 | 2 SCl4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2 | 3 | -3 | ([Cl2])^(-3) H_2S | 1 | -1 | ([H2S])^(-1) HCl | 2 | 2 | ([HCl])^2 SCl4 | 1 | 1 | [SCl4] 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 = ([Cl2])^(-3) ([H2S])^(-1) ([HCl])^2 [SCl4] = (([HCl])^2 [SCl4])/(([Cl2])^3 [H2S])

Construct the rate of reaction expression for: Cl_2 + H_2S ⟶ HCl + SCl4 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: 3 Cl_2 + H_2S ⟶ 2 HCl + SCl4 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 Cl_2 | 3 | -3 H_2S | 1 | -1 HCl | 2 | 2 SCl4 | 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 Cl_2 | 3 | -3 | -1/3 (Δ[Cl2])/(Δt) H_2S | 1 | -1 | -(Δ[H2S])/(Δt) HCl | 2 | 2 | 1/2 (Δ[HCl])/(Δt) SCl4 | 1 | 1 | (Δ[SCl4])/(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 = -1/3 (Δ[Cl2])/(Δt) = -(Δ[H2S])/(Δt) = 1/2 (Δ[HCl])/(Δt) = (Δ[SCl4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| chlorine | hydrogen sulfide | hydrogen chloride | SCl4 formula | Cl_2 | H_2S | HCl | SCl4 Hill formula | Cl_2 | H_2S | ClH | Cl4S name | chlorine | hydrogen sulfide | hydrogen chloride | IUPAC name | molecular chlorine | hydrogen sulfide | hydrogen chloride |

| chlorine | hydrogen sulfide | hydrogen chloride | SCl4 molar mass | 70.9 g/mol | 34.08 g/mol | 36.46 g/mol | 173.9 g/mol phase | gas (at STP) | gas (at STP) | gas (at STP) | melting point | -101 °C | -85 °C | -114.17 °C | boiling point | -34 °C | -60 °C | -85 °C | density | 0.003214 g/cm^3 (at 0 °C) | 0.001393 g/cm^3 (at 25 °C) | 0.00149 g/cm^3 (at 25 °C) | solubility in water | | | miscible | dynamic viscosity | | 1.239×10^-5 Pa s (at 25 °C) | |