Na2S + NaClO3 = NaCl + Na2SO4

Na_2S sodium sulfide + NaClO_3 sodium chlorate ⟶ NaCl sodium chloride + Na_2SO_4 sodium sulfate

Balance the chemical equation algebraically: Na_2S + NaClO_3 ⟶ NaCl + Na_2SO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Na_2S + c_2 NaClO_3 ⟶ c_3 NaCl + c_4 Na_2SO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for Na, S, Cl and O: Na: | 2 c_1 + c_2 = c_3 + 2 c_4 S: | c_1 = c_4 Cl: | c_2 = c_3 O: | 3 c_2 = 4 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 4/3 c_3 = 4/3 c_4 = 1 Multiply by the least common denominator, 3, to eliminate fractional coefficients: c_1 = 3 c_2 = 4 c_3 = 4 c_4 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 Na_2S + 4 NaClO_3 ⟶ 4 NaCl + 3 Na_2SO_4

+ ⟶ +

sodium sulfide + sodium chlorate ⟶ sodium chloride + sodium sulfate

Construct the equilibrium constant, K, expression for: Na_2S + NaClO_3 ⟶ NaCl + Na_2SO_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: 3 Na_2S + 4 NaClO_3 ⟶ 4 NaCl + 3 Na_2SO_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 Na_2S | 3 | -3 NaClO_3 | 4 | -4 NaCl | 4 | 4 Na_2SO_4 | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Na_2S | 3 | -3 | ([Na2S])^(-3) NaClO_3 | 4 | -4 | ([NaClO3])^(-4) NaCl | 4 | 4 | ([NaCl])^4 Na_2SO_4 | 3 | 3 | ([Na2SO4])^3 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 = ([Na2S])^(-3) ([NaClO3])^(-4) ([NaCl])^4 ([Na2SO4])^3 = (([NaCl])^4 ([Na2SO4])^3)/(([Na2S])^3 ([NaClO3])^4)

Construct the rate of reaction expression for: Na_2S + NaClO_3 ⟶ NaCl + Na_2SO_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: 3 Na_2S + 4 NaClO_3 ⟶ 4 NaCl + 3 Na_2SO_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 Na_2S | 3 | -3 NaClO_3 | 4 | -4 NaCl | 4 | 4 Na_2SO_4 | 3 | 3 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 Na_2S | 3 | -3 | -1/3 (Δ[Na2S])/(Δt) NaClO_3 | 4 | -4 | -1/4 (Δ[NaClO3])/(Δt) NaCl | 4 | 4 | 1/4 (Δ[NaCl])/(Δt) Na_2SO_4 | 3 | 3 | 1/3 (Δ[Na2SO4])/(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[Na2S])/(Δt) = -1/4 (Δ[NaClO3])/(Δt) = 1/4 (Δ[NaCl])/(Δt) = 1/3 (Δ[Na2SO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium sulfide | sodium chlorate | sodium chloride | sodium sulfate formula | Na_2S | NaClO_3 | NaCl | Na_2SO_4 Hill formula | Na_2S_1 | ClNaO_3 | ClNa | Na_2O_4S name | sodium sulfide | sodium chlorate | sodium chloride | sodium sulfate IUPAC name | | sodium chlorate | sodium chloride | disodium sulfate

| sodium sulfide | sodium chlorate | sodium chloride | sodium sulfate molar mass | 78.04 g/mol | 106.4 g/mol | 58.44 g/mol | 142.04 g/mol phase | solid (at STP) | liquid (at STP) | solid (at STP) | solid (at STP) melting point | 1172 °C | | 801 °C | 884 °C boiling point | | 106 °C | 1413 °C | 1429 °C density | 1.856 g/cm^3 | 1.3 g/cm^3 | 2.16 g/cm^3 | 2.68 g/cm^3 solubility in water | | very soluble | soluble | soluble dynamic viscosity | | 0.00542 Pa s (at 286 °C) | | odor | | odorless | odorless |