Br2 + SnCl2 = SnCl4 + SnBr4

Br_2 bromine + SnCl_2 stannous chloride ⟶ SnCl_4 stannic chloride + SnBr_4 tin(IV) bromide

Balance the chemical equation algebraically: Br_2 + SnCl_2 ⟶ SnCl_4 + SnBr_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Br_2 + c_2 SnCl_2 ⟶ c_3 SnCl_4 + c_4 SnBr_4 Set the number of atoms in the reactants equal to the number of atoms in the products for Br, Cl and Sn: Br: | 2 c_1 = 4 c_4 Cl: | 2 c_2 = 4 c_3 Sn: | c_2 = c_3 + c_4 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 2 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 Br_2 + 2 SnCl_2 ⟶ SnCl_4 + SnBr_4

+ ⟶ +

bromine + stannous chloride ⟶ stannic chloride + tin(IV) bromide

Construct the equilibrium constant, K, expression for: Br_2 + SnCl_2 ⟶ SnCl_4 + SnBr_4 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 Br_2 + 2 SnCl_2 ⟶ SnCl_4 + SnBr_4 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 Br_2 | 2 | -2 SnCl_2 | 2 | -2 SnCl_4 | 1 | 1 SnBr_4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Br_2 | 2 | -2 | ([Br2])^(-2) SnCl_2 | 2 | -2 | ([SnCl2])^(-2) SnCl_4 | 1 | 1 | [SnCl4] SnBr_4 | 1 | 1 | [SnBr4] 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 = ([Br2])^(-2) ([SnCl2])^(-2) [SnCl4] [SnBr4] = ([SnCl4] [SnBr4])/(([Br2])^2 ([SnCl2])^2)

Construct the rate of reaction expression for: Br_2 + SnCl_2 ⟶ SnCl_4 + SnBr_4 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 Br_2 + 2 SnCl_2 ⟶ SnCl_4 + SnBr_4 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 Br_2 | 2 | -2 SnCl_2 | 2 | -2 SnCl_4 | 1 | 1 SnBr_4 | 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 Br_2 | 2 | -2 | -1/2 (Δ[Br2])/(Δt) SnCl_2 | 2 | -2 | -1/2 (Δ[SnCl2])/(Δt) SnCl_4 | 1 | 1 | (Δ[SnCl4])/(Δt) SnBr_4 | 1 | 1 | (Δ[SnBr4])/(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[Br2])/(Δt) = -1/2 (Δ[SnCl2])/(Δt) = (Δ[SnCl4])/(Δt) = (Δ[SnBr4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| bromine | stannous chloride | stannic chloride | tin(IV) bromide formula | Br_2 | SnCl_2 | SnCl_4 | SnBr_4 Hill formula | Br_2 | Cl_2Sn | Cl_4Sn | Br_4Sn name | bromine | stannous chloride | stannic chloride | tin(IV) bromide IUPAC name | molecular bromine | dichlorotin | tetrachlorostannane | tetrabromostannane

| bromine | stannous chloride | stannic chloride | tin(IV) bromide molar mass | 159.81 g/mol | 189.6 g/mol | 260.5 g/mol | 438.33 g/mol phase | liquid (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) melting point | -7.2 °C | 246 °C | -33 °C | 31 °C boiling point | 58.8 °C | 652 °C | 114 °C | 202 °C density | 3.119 g/cm^3 | 3.354 g/cm^3 | 2.226 g/cm^3 | 3.34 g/cm^3 solubility in water | insoluble | | soluble | soluble surface tension | 0.0409 N/m | | | dynamic viscosity | 9.44×10^-4 Pa s (at 25 °C) | 7 Pa s (at 25 °C) | 5.8×10^-4 Pa s (at 60 °C) | odor | | odorless | |