SO2 + Al2O3 = Al2(SO3)3

SO_2 sulfur dioxide + Al_2O_3 aluminum oxide ⟶ Al2(SO3)3

Balance the chemical equation algebraically: SO_2 + Al_2O_3 ⟶ Al2(SO3)3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 SO_2 + c_2 Al_2O_3 ⟶ c_3 Al2(SO3)3 Set the number of atoms in the reactants equal to the number of atoms in the products for O, S and Al: O: | 2 c_1 + 3 c_2 = 9 c_3 S: | c_1 = 3 c_3 Al: | 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3 c_2 = 1 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 SO_2 + Al_2O_3 ⟶ Al2(SO3)3

+ ⟶ Al2(SO3)3

sulfur dioxide + aluminum oxide ⟶ Al2(SO3)3

Construct the equilibrium constant, K, expression for: SO_2 + Al_2O_3 ⟶ Al2(SO3)3 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 SO_2 + Al_2O_3 ⟶ Al2(SO3)3 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 SO_2 | 3 | -3 Al_2O_3 | 1 | -1 Al2(SO3)3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression SO_2 | 3 | -3 | ([SO2])^(-3) Al_2O_3 | 1 | -1 | ([Al2O3])^(-1) Al2(SO3)3 | 1 | 1 | [Al2(SO3)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 = ([SO2])^(-3) ([Al2O3])^(-1) [Al2(SO3)3] = ([Al2(SO3)3])/(([SO2])^3 [Al2O3])

Construct the rate of reaction expression for: SO_2 + Al_2O_3 ⟶ Al2(SO3)3 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 SO_2 + Al_2O_3 ⟶ Al2(SO3)3 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 SO_2 | 3 | -3 Al_2O_3 | 1 | -1 Al2(SO3)3 | 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 SO_2 | 3 | -3 | -1/3 (Δ[SO2])/(Δt) Al_2O_3 | 1 | -1 | -(Δ[Al2O3])/(Δt) Al2(SO3)3 | 1 | 1 | (Δ[Al2(SO3)3])/(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[SO2])/(Δt) = -(Δ[Al2O3])/(Δt) = (Δ[Al2(SO3)3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfur dioxide | aluminum oxide | Al2(SO3)3 formula | SO_2 | Al_2O_3 | Al2(SO3)3 Hill formula | O_2S | Al_2O_3 | Al2O9S3 name | sulfur dioxide | aluminum oxide | IUPAC name | sulfur dioxide | dialuminum;oxygen(2-) |

| sulfur dioxide | aluminum oxide | Al2(SO3)3 molar mass | 64.06 g/mol | 101.96 g/mol | 294.1 g/mol phase | gas (at STP) | solid (at STP) | melting point | -73 °C | 2040 °C | boiling point | -10 °C | | density | 0.002619 g/cm^3 (at 25 °C) | | surface tension | 0.02859 N/m | | dynamic viscosity | 1.282×10^-5 Pa s (at 25 °C) | | odor | | odorless |