KClO3 + Na2SO3 = KCl + Na2SO4

KClO_3 potassium chlorate + Na_2SO_3 sodium sulfite ⟶ KCl potassium chloride + Na_2SO_4 sodium sulfate

Balance the chemical equation algebraically: KClO_3 + Na_2SO_3 ⟶ KCl + Na_2SO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 KClO_3 + c_2 Na_2SO_3 ⟶ c_3 KCl + c_4 Na_2SO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, K, O, Na and S: Cl: | c_1 = c_3 K: | c_1 = c_3 O: | 3 c_1 + 3 c_2 = 4 c_4 Na: | 2 c_2 = 2 c_4 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 3 c_3 = 1 c_4 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | KClO_3 + 3 Na_2SO_3 ⟶ KCl + 3 Na_2SO_4

+ ⟶ +

potassium chlorate + sodium sulfite ⟶ potassium chloride + sodium sulfate

| potassium chlorate | sodium sulfite | potassium chloride | sodium sulfate molecular enthalpy | -397.7 kJ/mol | -1101 kJ/mol | -436.5 kJ/mol | -1387 kJ/mol total enthalpy | -397.7 kJ/mol | -3302 kJ/mol | -436.5 kJ/mol | -4161 kJ/mol | H_initial = -3700 kJ/mol | | H_final = -4598 kJ/mol | ΔH_rxn^0 | -4598 kJ/mol - -3700 kJ/mol = -897.7 kJ/mol (exothermic) | | |

| potassium chlorate | sodium sulfite | potassium chloride | sodium sulfate molecular free energy | -296.3 kJ/mol | -10125 kJ/mol | -408.5 kJ/mol | -1270 kJ/mol total free energy | -296.3 kJ/mol | -30375 kJ/mol | -408.5 kJ/mol | -3811 kJ/mol | G_initial = -30671 kJ/mol | | G_final = -4219 kJ/mol | ΔG_rxn^0 | -4219 kJ/mol - -30671 kJ/mol = 26452 kJ/mol (endergonic) | | |

Construct the equilibrium constant, K, expression for: KClO_3 + Na_2SO_3 ⟶ KCl + 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: KClO_3 + 3 Na_2SO_3 ⟶ KCl + 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 KClO_3 | 1 | -1 Na_2SO_3 | 3 | -3 KCl | 1 | 1 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 KClO_3 | 1 | -1 | ([KClO3])^(-1) Na_2SO_3 | 3 | -3 | ([Na2SO3])^(-3) KCl | 1 | 1 | [KCl] 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 = ([KClO3])^(-1) ([Na2SO3])^(-3) [KCl] ([Na2SO4])^3 = ([KCl] ([Na2SO4])^3)/([KClO3] ([Na2SO3])^3)

Construct the rate of reaction expression for: KClO_3 + Na_2SO_3 ⟶ KCl + 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: KClO_3 + 3 Na_2SO_3 ⟶ KCl + 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 KClO_3 | 1 | -1 Na_2SO_3 | 3 | -3 KCl | 1 | 1 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 KClO_3 | 1 | -1 | -(Δ[KClO3])/(Δt) Na_2SO_3 | 3 | -3 | -1/3 (Δ[Na2SO3])/(Δt) KCl | 1 | 1 | (Δ[KCl])/(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 = -(Δ[KClO3])/(Δt) = -1/3 (Δ[Na2SO3])/(Δt) = (Δ[KCl])/(Δt) = 1/3 (Δ[Na2SO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| potassium chlorate | sodium sulfite | potassium chloride | sodium sulfate formula | KClO_3 | Na_2SO_3 | KCl | Na_2SO_4 Hill formula | ClKO_3 | Na_2O_3S | ClK | Na_2O_4S name | potassium chlorate | sodium sulfite | potassium chloride | sodium sulfate IUPAC name | potassium chlorate | disodium sulfite | potassium chloride | disodium sulfate

| potassium chlorate | sodium sulfite | potassium chloride | sodium sulfate molar mass | 122.5 g/mol | 126.04 g/mol | 74.55 g/mol | 142.04 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) melting point | 356 °C | 500 °C | 770 °C | 884 °C boiling point | | | 1420 °C | 1429 °C density | 2.34 g/cm^3 | 2.63 g/cm^3 | 1.98 g/cm^3 | 2.68 g/cm^3 solubility in water | soluble | | soluble | soluble odor | | | odorless |