H2S + Na2O = H2O + Na2S

H_2S hydrogen sulfide + Na_2O sodium oxide ⟶ H_2O water + Na_2S sodium sulfide

Balance the chemical equation algebraically: H_2S + Na_2O ⟶ H_2O + Na_2S Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2S + c_2 Na_2O ⟶ c_3 H_2O + c_4 Na_2S Set the number of atoms in the reactants equal to the number of atoms in the products for H, S, Na and O: H: | 2 c_1 = 2 c_3 S: | c_1 = c_4 Na: | 2 c_2 = 2 c_4 O: | c_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_2S + Na_2O ⟶ H_2O + Na_2S

+ ⟶ +

hydrogen sulfide + sodium oxide ⟶ water + sodium sulfide

Construct the equilibrium constant, K, expression for: H_2S + Na_2O ⟶ H_2O + Na_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_2S + Na_2O ⟶ H_2O + Na_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_2S | 1 | -1 Na_2O | 1 | -1 H_2O | 1 | 1 Na_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_2S | 1 | -1 | ([H2S])^(-1) Na_2O | 1 | -1 | ([Na2O])^(-1) H_2O | 1 | 1 | [H2O] Na_2S | 1 | 1 | [Na2S] 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) ([Na2O])^(-1) [H2O] [Na2S] = ([H2O] [Na2S])/([H2S] [Na2O])

Construct the rate of reaction expression for: H_2S + Na_2O ⟶ H_2O + Na_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_2S + Na_2O ⟶ H_2O + Na_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_2S | 1 | -1 Na_2O | 1 | -1 H_2O | 1 | 1 Na_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_2S | 1 | -1 | -(Δ[H2S])/(Δt) Na_2O | 1 | -1 | -(Δ[Na2O])/(Δt) H_2O | 1 | 1 | (Δ[H2O])/(Δt) Na_2S | 1 | 1 | (Δ[Na2S])/(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[Na2O])/(Δt) = (Δ[H2O])/(Δt) = (Δ[Na2S])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen sulfide | sodium oxide | water | sodium sulfide formula | H_2S | Na_2O | H_2O | Na_2S Hill formula | H_2S | Na_2O | H_2O | Na_2S_1 name | hydrogen sulfide | sodium oxide | water | sodium sulfide IUPAC name | hydrogen sulfide | disodium oxygen(-2) anion | water |

| hydrogen sulfide | sodium oxide | water | sodium sulfide molar mass | 34.08 g/mol | 61.979 g/mol | 18.015 g/mol | 78.04 g/mol phase | gas (at STP) | | liquid (at STP) | solid (at STP) melting point | -85 °C | | 0 °C | 1172 °C boiling point | -60 °C | | 99.9839 °C | density | 0.001393 g/cm^3 (at 25 °C) | 2.27 g/cm^3 | 1 g/cm^3 | 1.856 g/cm^3 surface tension | | | 0.0728 N/m | dynamic viscosity | 1.239×10^-5 Pa s (at 25 °C) | | 8.9×10^-4 Pa s (at 25 °C) | odor | | | odorless |