CaCO3 + ZnCl2 = CaCl2 + ZnCO3

CaCO_3 calcium carbonate + ZnCl_2 zinc chloride ⟶ CaCl_2 calcium chloride + ZnCO_3 zinc carbonate

Balance the chemical equation algebraically: CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 CaCO_3 + c_2 ZnCl_2 ⟶ c_3 CaCl_2 + c_4 ZnCO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for C, Ca, O, Cl and Zn: C: | c_1 = c_4 Ca: | c_1 = c_3 O: | 3 c_1 = 3 c_4 Cl: | 2 c_2 = 2 c_3 Zn: | 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 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_3

+ ⟶ +

calcium carbonate + zinc chloride ⟶ calcium chloride + zinc carbonate

Construct the equilibrium constant, K, expression for: CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_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: CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_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 CaCO_3 | 1 | -1 ZnCl_2 | 1 | -1 CaCl_2 | 1 | 1 ZnCO_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression CaCO_3 | 1 | -1 | ([CaCO3])^(-1) ZnCl_2 | 1 | -1 | ([ZnCl2])^(-1) CaCl_2 | 1 | 1 | [CaCl2] ZnCO_3 | 1 | 1 | [ZnCO3] 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 = ([CaCO3])^(-1) ([ZnCl2])^(-1) [CaCl2] [ZnCO3] = ([CaCl2] [ZnCO3])/([CaCO3] [ZnCl2])

Construct the rate of reaction expression for: CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_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: CaCO_3 + ZnCl_2 ⟶ CaCl_2 + ZnCO_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 CaCO_3 | 1 | -1 ZnCl_2 | 1 | -1 CaCl_2 | 1 | 1 ZnCO_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 CaCO_3 | 1 | -1 | -(Δ[CaCO3])/(Δt) ZnCl_2 | 1 | -1 | -(Δ[ZnCl2])/(Δt) CaCl_2 | 1 | 1 | (Δ[CaCl2])/(Δt) ZnCO_3 | 1 | 1 | (Δ[ZnCO3])/(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[CaCO3])/(Δt) = -(Δ[ZnCl2])/(Δt) = (Δ[CaCl2])/(Δt) = (Δ[ZnCO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| calcium carbonate | zinc chloride | calcium chloride | zinc carbonate formula | CaCO_3 | ZnCl_2 | CaCl_2 | ZnCO_3 Hill formula | CCaO_3 | Cl_2Zn | CaCl_2 | CO_3Zn name | calcium carbonate | zinc chloride | calcium chloride | zinc carbonate IUPAC name | calcium carbonate | zinc dichloride | calcium dichloride | zinc carbonate

| calcium carbonate | zinc chloride | calcium chloride | zinc carbonate molar mass | 100.09 g/mol | 136.3 g/mol | 111 g/mol | 125.4 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 1340 °C | 293 °C | 772 °C | density | 2.71 g/cm^3 | | 2.15 g/cm^3 | 4.3476 g/cm^3 solubility in water | insoluble | soluble | soluble | insoluble odor | | odorless | |