Na2SO3 + Ca = Na + CaSO3

Na_2SO_3 sodium sulfite + Ca calcium ⟶ Na sodium + CaSO3

Balance the chemical equation algebraically: Na_2SO_3 + Ca ⟶ Na + CaSO3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Na_2SO_3 + c_2 Ca ⟶ c_3 Na + c_4 CaSO3 Set the number of atoms in the reactants equal to the number of atoms in the products for Na, O, S and Ca: Na: | 2 c_1 = c_3 O: | 3 c_1 = 3 c_4 S: | c_1 = c_4 Ca: | 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 = 1 c_3 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Na_2SO_3 + Ca ⟶ 2 Na + CaSO3

+ ⟶ + CaSO3

sodium sulfite + calcium ⟶ sodium + CaSO3

Construct the equilibrium constant, K, expression for: Na_2SO_3 + Ca ⟶ Na + CaSO3 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: Na_2SO_3 + Ca ⟶ 2 Na + CaSO3 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_2SO_3 | 1 | -1 Ca | 1 | -1 Na | 2 | 2 CaSO3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Na_2SO_3 | 1 | -1 | ([Na2SO3])^(-1) Ca | 1 | -1 | ([Ca])^(-1) Na | 2 | 2 | ([Na])^2 CaSO3 | 1 | 1 | [CaSO3] 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 = ([Na2SO3])^(-1) ([Ca])^(-1) ([Na])^2 [CaSO3] = (([Na])^2 [CaSO3])/([Na2SO3] [Ca])

Construct the rate of reaction expression for: Na_2SO_3 + Ca ⟶ Na + CaSO3 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: Na_2SO_3 + Ca ⟶ 2 Na + CaSO3 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_2SO_3 | 1 | -1 Ca | 1 | -1 Na | 2 | 2 CaSO3 | 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 Na_2SO_3 | 1 | -1 | -(Δ[Na2SO3])/(Δt) Ca | 1 | -1 | -(Δ[Ca])/(Δt) Na | 2 | 2 | 1/2 (Δ[Na])/(Δt) CaSO3 | 1 | 1 | (Δ[CaSO3])/(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[Na2SO3])/(Δt) = -(Δ[Ca])/(Δt) = 1/2 (Δ[Na])/(Δt) = (Δ[CaSO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium sulfite | calcium | sodium | CaSO3 formula | Na_2SO_3 | Ca | Na | CaSO3 Hill formula | Na_2O_3S | Ca | Na | CaO3S name | sodium sulfite | calcium | sodium | IUPAC name | disodium sulfite | calcium | sodium |

| sodium sulfite | calcium | sodium | CaSO3 molar mass | 126.04 g/mol | 40.078 g/mol | 22.98976928 g/mol | 120.1 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 500 °C | 850 °C | 97.8 °C | boiling point | | 1484 °C | 883 °C | density | 2.63 g/cm^3 | 1.54 g/cm^3 | 0.968 g/cm^3 | solubility in water | | decomposes | decomposes | dynamic viscosity | | | 1.413×10^-5 Pa s (at 527 °C) |