H2SO4 + HNO3 + FeSO4 = H2O + NO + Fe2(SO4)3

H_2SO_4 (sulfuric acid) + HNO_3 (nitric acid) + FeSO_4 (duretter) ⟶ H_2O (water) + NO (nitric oxide) + Fe_2(SO_4)_3·xH_2O (iron(III) sulfate hydrate)

Balance the chemical equation algebraically: H_2SO_4 + HNO_3 + FeSO_4 ⟶ H_2O + NO + Fe_2(SO_4)_3·xH_2O Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 HNO_3 + c_3 FeSO_4 ⟶ c_4 H_2O + c_5 NO + c_6 Fe_2(SO_4)_3·xH_2O Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S, N and Fe: H: | 2 c_1 + c_2 = 2 c_4 O: | 4 c_1 + 3 c_2 + 4 c_3 = c_4 + c_5 + 12 c_6 S: | c_1 + c_3 = 3 c_6 N: | c_2 = c_5 Fe: | c_3 = 2 c_6 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 = 3/2 c_2 = 1 c_3 = 3 c_4 = 2 c_5 = 1 c_6 = 3/2 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 3 c_2 = 2 c_3 = 6 c_4 = 4 c_5 = 2 c_6 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 H_2SO_4 + 2 HNO_3 + 6 FeSO_4 ⟶ 4 H_2O + 2 NO + 3 Fe_2(SO_4)_3·xH_2O

+ + ⟶ + +

sulfuric acid + nitric acid + duretter ⟶ water + nitric oxide + iron(III) sulfate hydrate

Construct the equilibrium constant, K, expression for: H_2SO_4 + HNO_3 + FeSO_4 ⟶ H_2O + NO + Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 + 2 HNO_3 + 6 FeSO_4 ⟶ 4 H_2O + 2 NO + 3 Fe_2(SO_4)_3·xH_2O 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_2SO_4 | 3 | -3 HNO_3 | 2 | -2 FeSO_4 | 6 | -6 H_2O | 4 | 4 NO | 2 | 2 Fe_2(SO_4)_3·xH_2O | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2SO_4 | 3 | -3 | ([H2SO4])^(-3) HNO_3 | 2 | -2 | ([HNO3])^(-2) FeSO_4 | 6 | -6 | ([FeSO4])^(-6) H_2O | 4 | 4 | ([H2O])^4 NO | 2 | 2 | ([NO])^2 Fe_2(SO_4)_3·xH_2O | 3 | 3 | ([Fe2(SO4)3·xH2O])^3 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 = ([H2SO4])^(-3) ([HNO3])^(-2) ([FeSO4])^(-6) ([H2O])^4 ([NO])^2 ([Fe2(SO4)3·xH2O])^3 = (([H2O])^4 ([NO])^2 ([Fe2(SO4)3·xH2O])^3)/(([H2SO4])^3 ([HNO3])^2 ([FeSO4])^6)

Construct the rate of reaction expression for: H_2SO_4 + HNO_3 + FeSO_4 ⟶ H_2O + NO + Fe_2(SO_4)_3·xH_2O 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 H_2SO_4 + 2 HNO_3 + 6 FeSO_4 ⟶ 4 H_2O + 2 NO + 3 Fe_2(SO_4)_3·xH_2O 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_2SO_4 | 3 | -3 HNO_3 | 2 | -2 FeSO_4 | 6 | -6 H_2O | 4 | 4 NO | 2 | 2 Fe_2(SO_4)_3·xH_2O | 3 | 3 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_2SO_4 | 3 | -3 | -1/3 (Δ[H2SO4])/(Δt) HNO_3 | 2 | -2 | -1/2 (Δ[HNO3])/(Δt) FeSO_4 | 6 | -6 | -1/6 (Δ[FeSO4])/(Δt) H_2O | 4 | 4 | 1/4 (Δ[H2O])/(Δt) NO | 2 | 2 | 1/2 (Δ[NO])/(Δt) Fe_2(SO_4)_3·xH_2O | 3 | 3 | 1/3 (Δ[Fe2(SO4)3·xH2O])/(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[H2SO4])/(Δt) = -1/2 (Δ[HNO3])/(Δt) = -1/6 (Δ[FeSO4])/(Δt) = 1/4 (Δ[H2O])/(Δt) = 1/2 (Δ[NO])/(Δt) = 1/3 (Δ[Fe2(SO4)3·xH2O])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | nitric acid | duretter | water | nitric oxide | iron(III) sulfate hydrate formula | H_2SO_4 | HNO_3 | FeSO_4 | H_2O | NO | Fe_2(SO_4)_3·xH_2O Hill formula | H_2O_4S | HNO_3 | FeO_4S | H_2O | NO | Fe_2O_12S_3 name | sulfuric acid | nitric acid | duretter | water | nitric oxide | iron(III) sulfate hydrate IUPAC name | sulfuric acid | nitric acid | iron(+2) cation sulfate | water | nitric oxide | diferric trisulfate