HCl + CaCl2 = Cl2 + HCa

HCl hydrogen chloride + CaCl_2 calcium chloride ⟶ Cl_2 chlorine + HCa

Balance the chemical equation algebraically: HCl + CaCl_2 ⟶ Cl_2 + HCa Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 CaCl_2 ⟶ c_3 Cl_2 + c_4 HCa Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and Ca: Cl: | c_1 + 2 c_2 = 2 c_3 H: | 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 = 3/2 c_4 = 1 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 2 c_2 = 2 c_3 = 3 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 HCl + 2 CaCl_2 ⟶ 3 Cl_2 + 2 HCa

+ ⟶ + HCa

hydrogen chloride + calcium chloride ⟶ chlorine + HCa

Construct the equilibrium constant, K, expression for: HCl + CaCl_2 ⟶ Cl_2 + HCa 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 + 2 CaCl_2 ⟶ 3 Cl_2 + 2 HCa 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 CaCl_2 | 2 | -2 Cl_2 | 3 | 3 HCa | 2 | 2 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) CaCl_2 | 2 | -2 | ([CaCl2])^(-2) Cl_2 | 3 | 3 | ([Cl2])^3 HCa | 2 | 2 | ([HCa])^2 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) ([CaCl2])^(-2) ([Cl2])^3 ([HCa])^2 = (([Cl2])^3 ([HCa])^2)/(([HCl])^2 ([CaCl2])^2)

Construct the rate of reaction expression for: HCl + CaCl_2 ⟶ Cl_2 + HCa 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 + 2 CaCl_2 ⟶ 3 Cl_2 + 2 HCa 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 CaCl_2 | 2 | -2 Cl_2 | 3 | 3 HCa | 2 | 2 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) CaCl_2 | 2 | -2 | -1/2 (Δ[CaCl2])/(Δt) Cl_2 | 3 | 3 | 1/3 (Δ[Cl2])/(Δt) HCa | 2 | 2 | 1/2 (Δ[HCa])/(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) = -1/2 (Δ[CaCl2])/(Δt) = 1/3 (Δ[Cl2])/(Δt) = 1/2 (Δ[HCa])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen chloride | calcium chloride | chlorine | HCa formula | HCl | CaCl_2 | Cl_2 | HCa Hill formula | ClH | CaCl_2 | Cl_2 | HCa name | hydrogen chloride | calcium chloride | chlorine | IUPAC name | hydrogen chloride | calcium dichloride | molecular chlorine |

| hydrogen chloride | calcium chloride | chlorine | HCa molar mass | 36.46 g/mol | 111 g/mol | 70.9 g/mol | 41.086 g/mol phase | gas (at STP) | solid (at STP) | gas (at STP) | melting point | -114.17 °C | 772 °C | -101 °C | boiling point | -85 °C | | -34 °C | density | 0.00149 g/cm^3 (at 25 °C) | 2.15 g/cm^3 | 0.003214 g/cm^3 (at 0 °C) | solubility in water | miscible | soluble | |