Br2 + HgO = HgBr2 + Br2O

Br_2 bromine + HgO mercuric oxide ⟶ HgBr_2 mercuric bromide + Br2O

Balance the chemical equation algebraically: Br_2 + HgO ⟶ HgBr_2 + Br2O Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Br_2 + c_2 HgO ⟶ c_3 HgBr_2 + c_4 Br2O Set the number of atoms in the reactants equal to the number of atoms in the products for Br, Hg and O: Br: | 2 c_1 = 2 c_3 + 2 c_4 Hg: | c_2 = c_3 O: | c_2 = 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 Br_2 + HgO ⟶ HgBr_2 + Br2O

+ ⟶ + Br2O

bromine + mercuric oxide ⟶ mercuric bromide + Br2O

Construct the equilibrium constant, K, expression for: Br_2 + HgO ⟶ HgBr_2 + Br2O 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 + HgO ⟶ HgBr_2 + Br2O 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 HgO | 1 | -1 HgBr_2 | 1 | 1 Br2O | 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) HgO | 1 | -1 | ([HgO])^(-1) HgBr_2 | 1 | 1 | [HgBr2] Br2O | 1 | 1 | [Br2O] 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) ([HgO])^(-1) [HgBr2] [Br2O] = ([HgBr2] [Br2O])/(([Br2])^2 [HgO])

Construct the rate of reaction expression for: Br_2 + HgO ⟶ HgBr_2 + Br2O 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 + HgO ⟶ HgBr_2 + Br2O 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 HgO | 1 | -1 HgBr_2 | 1 | 1 Br2O | 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) HgO | 1 | -1 | -(Δ[HgO])/(Δt) HgBr_2 | 1 | 1 | (Δ[HgBr2])/(Δt) Br2O | 1 | 1 | (Δ[Br2O])/(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) = -(Δ[HgO])/(Δt) = (Δ[HgBr2])/(Δt) = (Δ[Br2O])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| bromine | mercuric oxide | mercuric bromide | Br2O formula | Br_2 | HgO | HgBr_2 | Br2O Hill formula | Br_2 | HgO | Br_2Hg | Br2O name | bromine | mercuric oxide | mercuric bromide | IUPAC name | molecular bromine | oxomercury | dibromomercury |

| bromine | mercuric oxide | mercuric bromide | Br2O molar mass | 159.81 g/mol | 216.591 g/mol | 360.4 g/mol | 175.81 g/mol phase | liquid (at STP) | solid (at STP) | solid (at STP) | melting point | -7.2 °C | 500 °C | 236 °C | boiling point | 58.8 °C | | 322 °C | density | 3.119 g/cm^3 | 11.14 g/cm^3 | 6.1 g/cm^3 | solubility in water | insoluble | insoluble | slightly soluble | surface tension | 0.0409 N/m | | | dynamic viscosity | 9.44×10^-4 Pa s (at 25 °C) | | | odor | | odorless | |