NaBr + Cl2Cl = NaCl + Br2

NaBr sodium bromide + Cl2Cl ⟶ NaCl sodium chloride + Br_2 bromine

Balance the chemical equation algebraically: NaBr + Cl2Cl ⟶ NaCl + Br_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaBr + c_2 Cl2Cl ⟶ c_3 NaCl + c_4 Br_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Br, Na and Cl: Br: | c_1 = 2 c_4 Na: | c_1 = c_3 Cl: | 3 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 = 3 c_2 = 1 c_3 = 3 c_4 = 3/2 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 6 c_2 = 2 c_3 = 6 c_4 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 6 NaBr + 2 Cl2Cl ⟶ 6 NaCl + 3 Br_2

+ Cl2Cl ⟶ +

sodium bromide + Cl2Cl ⟶ sodium chloride + bromine

Construct the equilibrium constant, K, expression for: NaBr + Cl2Cl ⟶ NaCl + Br_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: 6 NaBr + 2 Cl2Cl ⟶ 6 NaCl + 3 Br_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 NaBr | 6 | -6 Cl2Cl | 2 | -2 NaCl | 6 | 6 Br_2 | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaBr | 6 | -6 | ([NaBr])^(-6) Cl2Cl | 2 | -2 | ([Cl2Cl])^(-2) NaCl | 6 | 6 | ([NaCl])^6 Br_2 | 3 | 3 | ([Br2])^3 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 = ([NaBr])^(-6) ([Cl2Cl])^(-2) ([NaCl])^6 ([Br2])^3 = (([NaCl])^6 ([Br2])^3)/(([NaBr])^6 ([Cl2Cl])^2)

Construct the rate of reaction expression for: NaBr + Cl2Cl ⟶ NaCl + Br_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: 6 NaBr + 2 Cl2Cl ⟶ 6 NaCl + 3 Br_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 NaBr | 6 | -6 Cl2Cl | 2 | -2 NaCl | 6 | 6 Br_2 | 3 | 3 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 NaBr | 6 | -6 | -1/6 (Δ[NaBr])/(Δt) Cl2Cl | 2 | -2 | -1/2 (Δ[Cl2Cl])/(Δt) NaCl | 6 | 6 | 1/6 (Δ[NaCl])/(Δt) Br_2 | 3 | 3 | 1/3 (Δ[Br2])/(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 = -1/6 (Δ[NaBr])/(Δt) = -1/2 (Δ[Cl2Cl])/(Δt) = 1/6 (Δ[NaCl])/(Δt) = 1/3 (Δ[Br2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium bromide | Cl2Cl | sodium chloride | bromine formula | NaBr | Cl2Cl | NaCl | Br_2 Hill formula | BrNa | Cl3 | ClNa | Br_2 name | sodium bromide | | sodium chloride | bromine IUPAC name | sodium bromide | | sodium chloride | molecular bromine

| sodium bromide | Cl2Cl | sodium chloride | bromine molar mass | 102.89 g/mol | 106.3 g/mol | 58.44 g/mol | 159.81 g/mol phase | solid (at STP) | | solid (at STP) | liquid (at STP) melting point | 755 °C | | 801 °C | -7.2 °C boiling point | 1396 °C | | 1413 °C | 58.8 °C density | 3.2 g/cm^3 | | 2.16 g/cm^3 | 3.119 g/cm^3 solubility in water | soluble | | soluble | insoluble surface tension | | | | 0.0409 N/m dynamic viscosity | | | | 9.44×10^-4 Pa s (at 25 °C) odor | | | odorless |