Zn + CI2 = ZnCI2

Zn zinc + CI2 ⟶ ZnCI2

Balance the chemical equation algebraically: Zn + CI2 ⟶ ZnCI2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Zn + c_2 CI2 ⟶ c_3 ZnCI2 Set the number of atoms in the reactants equal to the number of atoms in the products for Zn, C and I: Zn: | c_1 = c_3 C: | c_2 = c_3 I: | 2 c_2 = 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: | | Zn + CI2 ⟶ ZnCI2

+ CI2 ⟶ ZnCI2

zinc + CI2 ⟶ ZnCI2

Construct the equilibrium constant, K, expression for: Zn + CI2 ⟶ ZnCI2 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: Zn + CI2 ⟶ ZnCI2 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 Zn | 1 | -1 CI2 | 1 | -1 ZnCI2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Zn | 1 | -1 | ([Zn])^(-1) CI2 | 1 | -1 | ([CI2])^(-1) ZnCI2 | 1 | 1 | [ZnCI2] 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 = ([Zn])^(-1) ([CI2])^(-1) [ZnCI2] = ([ZnCI2])/([Zn] [CI2])

Construct the rate of reaction expression for: Zn + CI2 ⟶ ZnCI2 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: Zn + CI2 ⟶ ZnCI2 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 Zn | 1 | -1 CI2 | 1 | -1 ZnCI2 | 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 Zn | 1 | -1 | -(Δ[Zn])/(Δt) CI2 | 1 | -1 | -(Δ[CI2])/(Δt) ZnCI2 | 1 | 1 | (Δ[ZnCI2])/(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[Zn])/(Δt) = -(Δ[CI2])/(Δt) = (Δ[ZnCI2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc | CI2 | ZnCI2 formula | Zn | CI2 | ZnCI2 Hill formula | Zn | CI2 | CI2Zn name | zinc | |

| zinc | CI2 | ZnCI2 molar mass | 65.38 g/mol | 265.82 g/mol | 331.2 g/mol phase | solid (at STP) | | melting point | 420 °C | | boiling point | 907 °C | | density | 7.14 g/cm^3 | | solubility in water | insoluble | | odor | odorless | |