H2S + HClO4 = H2SO4 + HCl

H_2S hydrogen sulfide + HClO_4 perchloric acid ⟶ H_2SO_4 sulfuric acid + HCl hydrogen chloride

Balance the chemical equation algebraically: H_2S + HClO_4 ⟶ H_2SO_4 + HCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2S + c_2 HClO_4 ⟶ c_3 H_2SO_4 + c_4 HCl Set the number of atoms in the reactants equal to the number of atoms in the products for H, S, Cl and O: H: | 2 c_1 + c_2 = 2 c_3 + c_4 S: | c_1 = c_3 Cl: | c_2 = c_4 O: | 4 c_2 = 4 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: | | H_2S + HClO_4 ⟶ H_2SO_4 + HCl

+ ⟶ +

hydrogen sulfide + perchloric acid ⟶ sulfuric acid + hydrogen chloride

Construct the equilibrium constant, K, expression for: H_2S + HClO_4 ⟶ H_2SO_4 + HCl 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_2S + HClO_4 ⟶ H_2SO_4 + HCl 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_2S | 1 | -1 HClO_4 | 1 | -1 H_2SO_4 | 1 | 1 HCl | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2S | 1 | -1 | ([H2S])^(-1) HClO_4 | 1 | -1 | ([HClO4])^(-1) H_2SO_4 | 1 | 1 | [H2SO4] HCl | 1 | 1 | [HCl] 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 = ([H2S])^(-1) ([HClO4])^(-1) [H2SO4] [HCl] = ([H2SO4] [HCl])/([H2S] [HClO4])

Construct the rate of reaction expression for: H_2S + HClO_4 ⟶ H_2SO_4 + HCl 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_2S + HClO_4 ⟶ H_2SO_4 + HCl 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_2S | 1 | -1 HClO_4 | 1 | -1 H_2SO_4 | 1 | 1 HCl | 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_2S | 1 | -1 | -(Δ[H2S])/(Δt) HClO_4 | 1 | -1 | -(Δ[HClO4])/(Δt) H_2SO_4 | 1 | 1 | (Δ[H2SO4])/(Δt) HCl | 1 | 1 | (Δ[HCl])/(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[H2S])/(Δt) = -(Δ[HClO4])/(Δt) = (Δ[H2SO4])/(Δt) = (Δ[HCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen sulfide | perchloric acid | sulfuric acid | hydrogen chloride formula | H_2S | HClO_4 | H_2SO_4 | HCl Hill formula | H_2S | ClHO_4 | H_2O_4S | ClH name | hydrogen sulfide | perchloric acid | sulfuric acid | hydrogen chloride

| hydrogen sulfide | perchloric acid | sulfuric acid | hydrogen chloride molar mass | 34.08 g/mol | 100.5 g/mol | 98.07 g/mol | 36.46 g/mol phase | gas (at STP) | liquid (at STP) | liquid (at STP) | gas (at STP) melting point | -85 °C | -112 °C | 10.371 °C | -114.17 °C boiling point | -60 °C | 90 °C | 279.6 °C | -85 °C density | 0.001393 g/cm^3 (at 25 °C) | 1.77 g/cm^3 | 1.8305 g/cm^3 | 0.00149 g/cm^3 (at 25 °C) solubility in water | | very soluble | very soluble | miscible surface tension | | | 0.0735 N/m | dynamic viscosity | 1.239×10^-5 Pa s (at 25 °C) | 8×10^-4 Pa s (at 25 °C) | 0.021 Pa s (at 25 °C) | odor | | odorless | odorless |