O2 + NH = H2O + NO

O_2 oxygen + NH ⟶ H_2O water + NO nitric oxide

Balance the chemical equation algebraically: O_2 + NH ⟶ H_2O + NO Add stoichiometric coefficients, c_i, to the reactants and products: c_1 O_2 + c_2 NH ⟶ c_3 H_2O + c_4 NO Set the number of atoms in the reactants equal to the number of atoms in the products for O, N and H: O: | 2 c_1 = c_3 + c_4 N: | c_2 = c_4 H: | 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 3/2 c_2 = 2 c_3 = 1 c_4 = 2 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 3 c_2 = 4 c_3 = 2 c_4 = 4 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 O_2 + 4 NH ⟶ 2 H_2O + 4 NO

+ NH ⟶ +

oxygen + NH ⟶ water + nitric oxide

Construct the equilibrium constant, K, expression for: O_2 + NH ⟶ H_2O + NO 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 O_2 + 4 NH ⟶ 2 H_2O + 4 NO 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 O_2 | 3 | -3 NH | 4 | -4 H_2O | 2 | 2 NO | 4 | 4 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression O_2 | 3 | -3 | ([O2])^(-3) NH | 4 | -4 | ([NH])^(-4) H_2O | 2 | 2 | ([H2O])^2 NO | 4 | 4 | ([NO])^4 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 = ([O2])^(-3) ([NH])^(-4) ([H2O])^2 ([NO])^4 = (([H2O])^2 ([NO])^4)/(([O2])^3 ([NH])^4)

Construct the rate of reaction expression for: O_2 + NH ⟶ H_2O + NO 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 O_2 + 4 NH ⟶ 2 H_2O + 4 NO 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 O_2 | 3 | -3 NH | 4 | -4 H_2O | 2 | 2 NO | 4 | 4 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 O_2 | 3 | -3 | -1/3 (Δ[O2])/(Δt) NH | 4 | -4 | -1/4 (Δ[NH])/(Δt) H_2O | 2 | 2 | 1/2 (Δ[H2O])/(Δt) NO | 4 | 4 | 1/4 (Δ[NO])/(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[O2])/(Δt) = -1/4 (Δ[NH])/(Δt) = 1/2 (Δ[H2O])/(Δt) = 1/4 (Δ[NO])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| oxygen | NH | water | nitric oxide formula | O_2 | NH | H_2O | NO Hill formula | O_2 | HN | H_2O | NO name | oxygen | | water | nitric oxide IUPAC name | molecular oxygen | | water | nitric oxide

| oxygen | NH | water | nitric oxide molar mass | 31.998 g/mol | 15.015 g/mol | 18.015 g/mol | 30.006 g/mol phase | gas (at STP) | | liquid (at STP) | gas (at STP) melting point | -218 °C | | 0 °C | -163.6 °C boiling point | -183 °C | | 99.9839 °C | -151.7 °C density | 0.001429 g/cm^3 (at 0 °C) | | 1 g/cm^3 | 0.001226 g/cm^3 (at 25 °C) surface tension | 0.01347 N/m | | 0.0728 N/m | dynamic viscosity | 2.055×10^-5 Pa s (at 25 °C) | | 8.9×10^-4 Pa s (at 25 °C) | 1.911×10^-5 Pa s (at 25 °C) odor | odorless | | odorless |