NaBr = Br2 + Na

NaBr sodium bromide ⟶ Br_2 bromine + Na sodium

Balance the chemical equation algebraically: NaBr ⟶ Br_2 + Na Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaBr ⟶ c_2 Br_2 + c_3 Na Set the number of atoms in the reactants equal to the number of atoms in the products for Br and Na: Br: | c_1 = 2 c_2 Na: | c_1 = 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 NaBr ⟶ Br_2 + 2 Na

⟶ +

sodium bromide ⟶ bromine + sodium

| sodium bromide | bromine | sodium molecular enthalpy | -361.1 kJ/mol | 0 kJ/mol | 0 kJ/mol total enthalpy | -722.2 kJ/mol | 0 kJ/mol | 0 kJ/mol | H_initial = -722.2 kJ/mol | H_final = 0 kJ/mol | ΔH_rxn^0 | 0 kJ/mol - -722.2 kJ/mol = 722.2 kJ/mol (endothermic) | |

| sodium bromide | bromine | sodium molecular entropy | 84 J/(mol K) | 152.2 J/(mol K) | 51 J/(mol K) total entropy | 168 J/(mol K) | 152.2 J/(mol K) | 102 J/(mol K) | S_initial = 168 J/(mol K) | S_final = 254.2 J/(mol K) | ΔS_rxn^0 | 254.2 J/(mol K) - 168 J/(mol K) = 86.23 J/(mol K) (endoentropic) | |

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

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

| sodium bromide | bromine | sodium formula | NaBr | Br_2 | Na Hill formula | BrNa | Br_2 | Na name | sodium bromide | bromine | sodium IUPAC name | sodium bromide | molecular bromine | sodium

| sodium bromide | bromine | sodium molar mass | 102.89 g/mol | 159.81 g/mol | 22.98976928 g/mol phase | solid (at STP) | liquid (at STP) | solid (at STP) melting point | 755 °C | -7.2 °C | 97.8 °C boiling point | 1396 °C | 58.8 °C | 883 °C density | 3.2 g/cm^3 | 3.119 g/cm^3 | 0.968 g/cm^3 solubility in water | soluble | insoluble | decomposes surface tension | | 0.0409 N/m | dynamic viscosity | | 9.44×10^-4 Pa s (at 25 °C) | 1.413×10^-5 Pa s (at 527 °C)