Cl2 + Al = AlCl

Cl_2 chlorine + Al aluminum ⟶ AlCl

Balance the chemical equation algebraically: Cl_2 + Al ⟶ AlCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 Al ⟶ c_3 AlCl Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and Al: Cl: | 2 c_1 = c_3 Al: | 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 2 c_3 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Cl_2 + 2 Al ⟶ 2 AlCl

+ ⟶ AlCl

chlorine + aluminum ⟶ AlCl

Construct the equilibrium constant, K, expression for: Cl_2 + Al ⟶ AlCl 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: Cl_2 + 2 Al ⟶ 2 AlCl 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 Cl_2 | 1 | -1 Al | 2 | -2 AlCl | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2 | 1 | -1 | ([Cl2])^(-1) Al | 2 | -2 | ([Al])^(-2) AlCl | 2 | 2 | ([AlCl])^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 = ([Cl2])^(-1) ([Al])^(-2) ([AlCl])^2 = ([AlCl])^2/([Cl2] ([Al])^2)

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

| chlorine | aluminum | AlCl formula | Cl_2 | Al | AlCl name | chlorine | aluminum | IUPAC name | molecular chlorine | aluminum |

| chlorine | aluminum | AlCl molar mass | 70.9 g/mol | 26.9815385 g/mol | 62.43 g/mol phase | gas (at STP) | solid (at STP) | melting point | -101 °C | 660.4 °C | boiling point | -34 °C | 2460 °C | density | 0.003214 g/cm^3 (at 0 °C) | 2.7 g/cm^3 | solubility in water | | insoluble | surface tension | | 0.817 N/m | dynamic viscosity | | 1.5×10^-4 Pa s (at 760 °C) | odor | | odorless |