Cl2 + NH3 = HCl + NCl3

Cl_2 chlorine + NH_3 ammonia ⟶ HCl hydrogen chloride + N_1Cl_3 nitrogen trichloride

Balance the chemical equation algebraically: Cl_2 + NH_3 ⟶ HCl + N_1Cl_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 NH_3 ⟶ c_3 HCl + c_4 N_1Cl_3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and N: Cl: | 2 c_1 = c_3 + 3 c_4 H: | 3 c_2 = c_3 N: | 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 = 3 c_2 = 1 c_3 = 3 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 Cl_2 + NH_3 ⟶ 3 HCl + N_1Cl_3

+ ⟶ +

chlorine + ammonia ⟶ hydrogen chloride + nitrogen trichloride

Construct the equilibrium constant, K, expression for: Cl_2 + NH_3 ⟶ HCl + N_1Cl_3 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: 3 Cl_2 + NH_3 ⟶ 3 HCl + N_1Cl_3 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 Cl_2 | 3 | -3 NH_3 | 1 | -1 HCl | 3 | 3 N_1Cl_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2 | 3 | -3 | ([Cl2])^(-3) NH_3 | 1 | -1 | ([NH3])^(-1) HCl | 3 | 3 | ([HCl])^3 N_1Cl_3 | 1 | 1 | [N1Cl3] 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 = ([Cl2])^(-3) ([NH3])^(-1) ([HCl])^3 [N1Cl3] = (([HCl])^3 [N1Cl3])/(([Cl2])^3 [NH3])

Construct the rate of reaction expression for: Cl_2 + NH_3 ⟶ HCl + N_1Cl_3 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: 3 Cl_2 + NH_3 ⟶ 3 HCl + N_1Cl_3 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 Cl_2 | 3 | -3 NH_3 | 1 | -1 HCl | 3 | 3 N_1Cl_3 | 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 Cl_2 | 3 | -3 | -1/3 (Δ[Cl2])/(Δt) NH_3 | 1 | -1 | -(Δ[NH3])/(Δt) HCl | 3 | 3 | 1/3 (Δ[HCl])/(Δt) N_1Cl_3 | 1 | 1 | (Δ[N1Cl3])/(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 = -1/3 (Δ[Cl2])/(Δt) = -(Δ[NH3])/(Δt) = 1/3 (Δ[HCl])/(Δt) = (Δ[N1Cl3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| chlorine | ammonia | hydrogen chloride | nitrogen trichloride formula | Cl_2 | NH_3 | HCl | N_1Cl_3 Hill formula | Cl_2 | H_3N | ClH | Cl_3N name | chlorine | ammonia | hydrogen chloride | nitrogen trichloride IUPAC name | molecular chlorine | ammonia | hydrogen chloride |

| chlorine | ammonia | hydrogen chloride | nitrogen trichloride molar mass | 70.9 g/mol | 17.031 g/mol | 36.46 g/mol | 120.4 g/mol phase | gas (at STP) | gas (at STP) | gas (at STP) | melting point | -101 °C | -77.73 °C | -114.17 °C | boiling point | -34 °C | -33.33 °C | -85 °C | density | 0.003214 g/cm^3 (at 0 °C) | 6.96×10^-4 g/cm^3 (at 25 °C) | 0.00149 g/cm^3 (at 25 °C) | solubility in water | | | miscible | surface tension | | 0.0234 N/m | | dynamic viscosity | | 1.009×10^-5 Pa s (at 25 °C) | |