LiH + BeCl2 = LiCl + BeH2

LiH lithium hydride + BeCl_2 beryllium chloride ⟶ LiCl lithium chloride + BeH_2 beryllium hydride

Balance the chemical equation algebraically: LiH + BeCl_2 ⟶ LiCl + BeH_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 LiH + c_2 BeCl_2 ⟶ c_3 LiCl + c_4 BeH_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H, Li, Be and Cl: H: | c_1 = 2 c_4 Li: | c_1 = c_3 Be: | c_2 = c_4 Cl: | 2 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 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 LiH + BeCl_2 ⟶ 2 LiCl + BeH_2

+ ⟶ +

lithium hydride + beryllium chloride ⟶ lithium chloride + beryllium hydride

Construct the equilibrium constant, K, expression for: LiH + BeCl_2 ⟶ LiCl + BeH_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: 2 LiH + BeCl_2 ⟶ 2 LiCl + BeH_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 LiH | 2 | -2 BeCl_2 | 1 | -1 LiCl | 2 | 2 BeH_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression LiH | 2 | -2 | ([LiH])^(-2) BeCl_2 | 1 | -1 | ([BeCl2])^(-1) LiCl | 2 | 2 | ([LiCl])^2 BeH_2 | 1 | 1 | [BeH2] 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 = ([LiH])^(-2) ([BeCl2])^(-1) ([LiCl])^2 [BeH2] = (([LiCl])^2 [BeH2])/(([LiH])^2 [BeCl2])

Construct the rate of reaction expression for: LiH + BeCl_2 ⟶ LiCl + BeH_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: 2 LiH + BeCl_2 ⟶ 2 LiCl + BeH_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 LiH | 2 | -2 BeCl_2 | 1 | -1 LiCl | 2 | 2 BeH_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 LiH | 2 | -2 | -1/2 (Δ[LiH])/(Δt) BeCl_2 | 1 | -1 | -(Δ[BeCl2])/(Δt) LiCl | 2 | 2 | 1/2 (Δ[LiCl])/(Δt) BeH_2 | 1 | 1 | (Δ[BeH2])/(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[LiH])/(Δt) = -(Δ[BeCl2])/(Δt) = 1/2 (Δ[LiCl])/(Δt) = (Δ[BeH2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| lithium hydride | beryllium chloride | lithium chloride | beryllium hydride formula | LiH | BeCl_2 | LiCl | BeH_2 Hill formula | HLi | BeCl_2 | ClLi | BeH_2 name | lithium hydride | beryllium chloride | lithium chloride | beryllium hydride IUPAC name | lithium hydride | beryllium dichloride | lithium chloride | beryllium;hydride

| lithium hydride | beryllium chloride | lithium chloride | beryllium hydride molar mass | 7.95 g/mol | 79.91 g/mol | 42.4 g/mol | 11.028 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 680 °C | 399 °C | 605 °C | boiling point | | 500 °C | 1382 °C | density | 0.82 g/cm^3 | 1.899 g/cm^3 | 2.07 g/cm^3 | 0.65 g/cm^3 solubility in water | reacts | | | dynamic viscosity | | | 0.00525 Pa s (at 20 °C) |