H2SO4 + K2S = K2SO4 + H2S

H_2SO_4 sulfuric acid + K2S ⟶ K_2SO_4 potassium sulfate + H_2S hydrogen sulfide

Balance the chemical equation algebraically: H_2SO_4 + K2S ⟶ K_2SO_4 + H_2S Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 K2S ⟶ c_3 K_2SO_4 + c_4 H_2S Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S and K: H: | 2 c_1 = 2 c_4 O: | 4 c_1 = 4 c_3 S: | c_1 + c_2 = c_3 + c_4 K: | 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: | | H_2SO_4 + K2S ⟶ K_2SO_4 + H_2S

+ K2S ⟶ +

sulfuric acid + K2S ⟶ potassium sulfate + hydrogen sulfide

Construct the equilibrium constant, K, expression for: H_2SO_4 + K2S ⟶ K_2SO_4 + H_2S 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 + K2S ⟶ K_2SO_4 + H_2S 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 K2S | 1 | -1 K_2SO_4 | 1 | 1 H_2S | 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) K2S | 1 | -1 | ([K2S])^(-1) K_2SO_4 | 1 | 1 | [K2SO4] H_2S | 1 | 1 | [H2S] 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) ([K2S])^(-1) [K2SO4] [H2S] = ([K2SO4] [H2S])/([H2SO4] [K2S])

Construct the rate of reaction expression for: H_2SO_4 + K2S ⟶ K_2SO_4 + H_2S 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 + K2S ⟶ K_2SO_4 + H_2S 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 K2S | 1 | -1 K_2SO_4 | 1 | 1 H_2S | 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) K2S | 1 | -1 | -(Δ[K2S])/(Δt) K_2SO_4 | 1 | 1 | (Δ[K2SO4])/(Δt) H_2S | 1 | 1 | (Δ[H2S])/(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[K2S])/(Δt) = (Δ[K2SO4])/(Δt) = (Δ[H2S])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | K2S | potassium sulfate | hydrogen sulfide formula | H_2SO_4 | K2S | K_2SO_4 | H_2S Hill formula | H_2O_4S | K2S | K_2O_4S | H_2S name | sulfuric acid | | potassium sulfate | hydrogen sulfide IUPAC name | sulfuric acid | | dipotassium sulfate | hydrogen sulfide

| sulfuric acid | K2S | potassium sulfate | hydrogen sulfide molar mass | 98.07 g/mol | 110.26 g/mol | 174.25 g/mol | 34.08 g/mol phase | liquid (at STP) | | | gas (at STP) melting point | 10.371 °C | | | -85 °C boiling point | 279.6 °C | | | -60 °C density | 1.8305 g/cm^3 | | | 0.001393 g/cm^3 (at 25 °C) solubility in water | very soluble | | soluble | surface tension | 0.0735 N/m | | | dynamic viscosity | 0.021 Pa s (at 25 °C) | | | 1.239×10^-5 Pa s (at 25 °C) odor | odorless | | |