Ag + ZnCl2 = Zn + AgCl

Ag silver + ZnCl_2 zinc chloride ⟶ Zn zinc + AgCl silver chloride

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

+ ⟶ +

silver + zinc chloride ⟶ zinc + silver chloride

| silver | zinc chloride | zinc | silver chloride molecular enthalpy | 0 kJ/mol | -415.1 kJ/mol | 0 kJ/mol | -127 kJ/mol total enthalpy | 0 kJ/mol | -415.1 kJ/mol | 0 kJ/mol | -254 kJ/mol | H_initial = -415.1 kJ/mol | | H_final = -254 kJ/mol | ΔH_rxn^0 | -254 kJ/mol - -415.1 kJ/mol = 161.1 kJ/mol (endothermic) | | |

Construct the equilibrium constant, K, expression for: Ag + ZnCl_2 ⟶ Zn + AgCl 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 Ag + ZnCl_2 ⟶ Zn + 2 AgCl 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 Ag | 2 | -2 ZnCl_2 | 1 | -1 Zn | 1 | 1 AgCl | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Ag | 2 | -2 | ([Ag])^(-2) ZnCl_2 | 1 | -1 | ([ZnCl2])^(-1) Zn | 1 | 1 | [Zn] AgCl | 2 | 2 | ([AgCl])^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 = ([Ag])^(-2) ([ZnCl2])^(-1) [Zn] ([AgCl])^2 = ([Zn] ([AgCl])^2)/(([Ag])^2 [ZnCl2])

Construct the rate of reaction expression for: Ag + ZnCl_2 ⟶ Zn + AgCl 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 Ag + ZnCl_2 ⟶ Zn + 2 AgCl 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 Ag | 2 | -2 ZnCl_2 | 1 | -1 Zn | 1 | 1 AgCl | 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 Ag | 2 | -2 | -1/2 (Δ[Ag])/(Δt) ZnCl_2 | 1 | -1 | -(Δ[ZnCl2])/(Δt) Zn | 1 | 1 | (Δ[Zn])/(Δt) AgCl | 2 | 2 | 1/2 (Δ[AgCl])/(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[Ag])/(Δt) = -(Δ[ZnCl2])/(Δt) = (Δ[Zn])/(Δt) = 1/2 (Δ[AgCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| silver | zinc chloride | zinc | silver chloride formula | Ag | ZnCl_2 | Zn | AgCl Hill formula | Ag | Cl_2Zn | Zn | AgCl name | silver | zinc chloride | zinc | silver chloride IUPAC name | silver | zinc dichloride | zinc | chlorosilver

| silver | zinc chloride | zinc | silver chloride molar mass | 107.8682 g/mol | 136.3 g/mol | 65.38 g/mol | 143.32 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) melting point | 960 °C | 293 °C | 420 °C | 455 °C boiling point | 2212 °C | | 907 °C | 1554 °C density | 10.49 g/cm^3 | | 7.14 g/cm^3 | 5.56 g/cm^3 solubility in water | insoluble | soluble | insoluble | odor | | odorless | odorless |