HCl + CaSO4 = H2SO4 + CaCl2

HCl hydrogen chloride + CaSO_4 calcium sulfate ⟶ H_2SO_4 sulfuric acid + CaCl_2 calcium chloride

Balance the chemical equation algebraically: HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 CaSO_4 ⟶ c_3 H_2SO_4 + c_4 CaCl_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H, Ca, O and S: Cl: | c_1 = 2 c_4 H: | c_1 = 2 c_3 Ca: | c_2 = c_4 O: | 4 c_2 = 4 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2

+ ⟶ +

hydrogen chloride + calcium sulfate ⟶ sulfuric acid + calcium chloride

Construct the equilibrium constant, K, expression for: HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2 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: 2 HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2 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 HCl | 2 | -2 CaSO_4 | 1 | -1 H_2SO_4 | 1 | 1 CaCl_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 2 | -2 | ([HCl])^(-2) CaSO_4 | 1 | -1 | ([CaSO4])^(-1) H_2SO_4 | 1 | 1 | [H2SO4] CaCl_2 | 1 | 1 | [CaCl2] 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 = ([HCl])^(-2) ([CaSO4])^(-1) [H2SO4] [CaCl2] = ([H2SO4] [CaCl2])/(([HCl])^2 [CaSO4])

Construct the rate of reaction expression for: HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2 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: 2 HCl + CaSO_4 ⟶ H_2SO_4 + CaCl_2 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 HCl | 2 | -2 CaSO_4 | 1 | -1 H_2SO_4 | 1 | 1 CaCl_2 | 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 HCl | 2 | -2 | -1/2 (Δ[HCl])/(Δt) CaSO_4 | 1 | -1 | -(Δ[CaSO4])/(Δt) H_2SO_4 | 1 | 1 | (Δ[H2SO4])/(Δt) CaCl_2 | 1 | 1 | (Δ[CaCl2])/(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 = -1/2 (Δ[HCl])/(Δt) = -(Δ[CaSO4])/(Δt) = (Δ[H2SO4])/(Δt) = (Δ[CaCl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen chloride | calcium sulfate | sulfuric acid | calcium chloride formula | HCl | CaSO_4 | H_2SO_4 | CaCl_2 Hill formula | ClH | CaO_4S | H_2O_4S | CaCl_2 name | hydrogen chloride | calcium sulfate | sulfuric acid | calcium chloride IUPAC name | hydrogen chloride | calcium sulfate | sulfuric acid | calcium dichloride

| hydrogen chloride | calcium sulfate | sulfuric acid | calcium chloride molar mass | 36.46 g/mol | 136.13 g/mol | 98.07 g/mol | 111 g/mol phase | gas (at STP) | | liquid (at STP) | solid (at STP) melting point | -114.17 °C | | 10.371 °C | 772 °C boiling point | -85 °C | | 279.6 °C | density | 0.00149 g/cm^3 (at 25 °C) | | 1.8305 g/cm^3 | 2.15 g/cm^3 solubility in water | miscible | slightly soluble | very soluble | soluble surface tension | | | 0.0735 N/m | dynamic viscosity | | | 0.021 Pa s (at 25 °C) | odor | | odorless | odorless |