Ca + SO3 = CaSO3

Ca calcium + SO_3 sulfur trioxide ⟶ CaSO3

Balance the chemical equation algebraically: Ca + SO_3 ⟶ CaSO3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Ca + c_2 SO_3 ⟶ c_3 CaSO3 Set the number of atoms in the reactants equal to the number of atoms in the products for Ca, O and S: Ca: | c_1 = c_3 O: | 3 c_2 = 3 c_3 S: | 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Ca + SO_3 ⟶ CaSO3

+ ⟶ CaSO3

calcium + sulfur trioxide ⟶ CaSO3

Construct the equilibrium constant, K, expression for: Ca + SO_3 ⟶ 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: Ca + SO_3 ⟶ 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 Ca | 1 | -1 SO_3 | 1 | -1 CaSO3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Ca | 1 | -1 | ([Ca])^(-1) SO_3 | 1 | -1 | ([SO3])^(-1) 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 = ([Ca])^(-1) ([SO3])^(-1) [CaSO3] = ([CaSO3])/([Ca] [SO3])

Construct the rate of reaction expression for: Ca + SO_3 ⟶ 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: Ca + SO_3 ⟶ 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 Ca | 1 | -1 SO_3 | 1 | -1 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 Ca | 1 | -1 | -(Δ[Ca])/(Δt) SO_3 | 1 | -1 | -(Δ[SO3])/(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[Ca])/(Δt) = -(Δ[SO3])/(Δt) = (Δ[CaSO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| calcium | sulfur trioxide | CaSO3 formula | Ca | SO_3 | CaSO3 Hill formula | Ca | O_3S | CaO3S name | calcium | sulfur trioxide |

| calcium | sulfur trioxide | CaSO3 molar mass | 40.078 g/mol | 80.06 g/mol | 120.1 g/mol phase | solid (at STP) | liquid (at STP) | melting point | 850 °C | 16.8 °C | boiling point | 1484 °C | 44.7 °C | density | 1.54 g/cm^3 | 1.97 g/cm^3 | solubility in water | decomposes | reacts | dynamic viscosity | | 0.00159 Pa s (at 30 °C) |