Cl2 + Be = BeCl2

Cl_2 chlorine + Be beryllium ⟶ BeCl_2 beryllium chloride

Balance the chemical equation algebraically: Cl_2 + Be ⟶ BeCl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 Be ⟶ c_3 BeCl_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and Be: Cl: | 2 c_1 = 2 c_3 Be: | 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 = 1 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Cl_2 + Be ⟶ BeCl_2

+ ⟶

chlorine + beryllium ⟶ beryllium chloride

| chlorine | beryllium | beryllium chloride molecular enthalpy | 0 kJ/mol | 0 kJ/mol | -490.4 kJ/mol total enthalpy | 0 kJ/mol | 0 kJ/mol | -490.4 kJ/mol | H_initial = 0 kJ/mol | | H_final = -490.4 kJ/mol ΔH_rxn^0 | -490.4 kJ/mol - 0 kJ/mol = -490.4 kJ/mol (exothermic) | |

Construct the equilibrium constant, K, expression for: Cl_2 + Be ⟶ BeCl_2 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 + Be ⟶ BeCl_2 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 Be | 1 | -1 BeCl_2 | 1 | 1 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) Be | 1 | -1 | ([Be])^(-1) BeCl_2 | 1 | 1 | [BeCl2] 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) ([Be])^(-1) [BeCl2] = ([BeCl2])/([Cl2] [Be])

Construct the rate of reaction expression for: Cl_2 + Be ⟶ BeCl_2 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 + Be ⟶ BeCl_2 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 Be | 1 | -1 BeCl_2 | 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 Cl_2 | 1 | -1 | -(Δ[Cl2])/(Δt) Be | 1 | -1 | -(Δ[Be])/(Δt) BeCl_2 | 1 | 1 | (Δ[BeCl2])/(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) = -(Δ[Be])/(Δt) = (Δ[BeCl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| chlorine | beryllium | beryllium chloride formula | Cl_2 | Be | BeCl_2 name | chlorine | beryllium | beryllium chloride IUPAC name | molecular chlorine | beryllium | beryllium dichloride

| chlorine | beryllium | beryllium chloride molar mass | 70.9 g/mol | 9.0121831 g/mol | 79.91 g/mol phase | gas (at STP) | solid (at STP) | solid (at STP) melting point | -101 °C | 1278 °C | 399 °C boiling point | -34 °C | 2970 °C | 500 °C density | 0.003214 g/cm^3 (at 0 °C) | 1.85 g/cm^3 | 1.899 g/cm^3 solubility in water | | insoluble |