H2O + N2 = NH4NO2

H_2O water + N_2 nitrogen ⟶ H_4N_2O_2 ammonium nitrite

Balance the chemical equation algebraically: H_2O + N_2 ⟶ H_4N_2O_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 N_2 ⟶ c_3 H_4N_2O_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O and N: H: | 2 c_1 = 4 c_3 O: | c_1 = 2 c_3 N: | 2 c_2 = 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 = 2 c_2 = 1 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 H_2O + N_2 ⟶ H_4N_2O_2

+ ⟶

water + nitrogen ⟶ ammonium nitrite

Construct the equilibrium constant, K, expression for: H_2O + N_2 ⟶ H_4N_2O_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: 2 H_2O + N_2 ⟶ H_4N_2O_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 H_2O | 2 | -2 N_2 | 1 | -1 H_4N_2O_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 2 | -2 | ([H2O])^(-2) N_2 | 1 | -1 | ([N2])^(-1) H_4N_2O_2 | 1 | 1 | [H4N2O2] 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 = ([H2O])^(-2) ([N2])^(-1) [H4N2O2] = ([H4N2O2])/(([H2O])^2 [N2])

Construct the rate of reaction expression for: H_2O + N_2 ⟶ H_4N_2O_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: 2 H_2O + N_2 ⟶ H_4N_2O_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 H_2O | 2 | -2 N_2 | 1 | -1 H_4N_2O_2 | 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 H_2O | 2 | -2 | -1/2 (Δ[H2O])/(Δt) N_2 | 1 | -1 | -(Δ[N2])/(Δt) H_4N_2O_2 | 1 | 1 | (Δ[H4N2O2])/(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[H2O])/(Δt) = -(Δ[N2])/(Δt) = (Δ[H4N2O2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| water | nitrogen | ammonium nitrite formula | H_2O | N_2 | H_4N_2O_2 name | water | nitrogen | ammonium nitrite IUPAC name | water | molecular nitrogen | azanium nitrite