Input interpretation
HCl hydrogen chloride + HNO_3 nitric acid + HgS mercury(II) sulfide ⟶ S mixed sulfur + NO nitric oxide + HgCl_2 mercuric chloride + H2O2O
Balanced equation
Balance the chemical equation algebraically: HCl + HNO_3 + HgS ⟶ S + NO + HgCl_2 + H2O2O Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 HNO_3 + c_3 HgS ⟶ c_4 S + c_5 NO + c_6 HgCl_2 + c_7 H2O2O Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H, N, O, Hg and S: Cl: | c_1 = 2 c_6 H: | c_1 + c_2 = 2 c_7 N: | c_2 = c_5 O: | 3 c_2 = c_5 + 3 c_7 Hg: | c_3 = c_6 S: | c_3 = 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 6 c_3 = 1 c_4 = 1 c_5 = 6 c_6 = 1 c_7 = 4 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 HCl + 6 HNO_3 + HgS ⟶ S + 6 NO + HgCl_2 + 4 H2O2O
Structures
+ + ⟶ + + + H2O2O
Names
hydrogen chloride + nitric acid + mercury(II) sulfide ⟶ mixed sulfur + nitric oxide + mercuric chloride + H2O2O
Equilibrium constant
Construct the equilibrium constant, K, expression for: HCl + HNO_3 + HgS ⟶ S + NO + HgCl_2 + H2O2O 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 HCl + 6 HNO_3 + HgS ⟶ S + 6 NO + HgCl_2 + 4 H2O2O 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 HCl | 2 | -2 HNO_3 | 6 | -6 HgS | 1 | -1 S | 1 | 1 NO | 6 | 6 HgCl_2 | 1 | 1 H2O2O | 4 | 4 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 2 | -2 | ([HCl])^(-2) HNO_3 | 6 | -6 | ([HNO3])^(-6) HgS | 1 | -1 | ([HgS])^(-1) S | 1 | 1 | [S] NO | 6 | 6 | ([NO])^6 HgCl_2 | 1 | 1 | [HgCl2] H2O2O | 4 | 4 | ([H2O2O])^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 = ([HCl])^(-2) ([HNO3])^(-6) ([HgS])^(-1) [S] ([NO])^6 [HgCl2] ([H2O2O])^4 = ([S] ([NO])^6 [HgCl2] ([H2O2O])^4)/(([HCl])^2 ([HNO3])^6 [HgS])
Rate of reaction
Construct the rate of reaction expression for: HCl + HNO_3 + HgS ⟶ S + NO + HgCl_2 + H2O2O 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 HCl + 6 HNO_3 + HgS ⟶ S + 6 NO + HgCl_2 + 4 H2O2O 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 HCl | 2 | -2 HNO_3 | 6 | -6 HgS | 1 | -1 S | 1 | 1 NO | 6 | 6 HgCl_2 | 1 | 1 H2O2O | 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 HCl | 2 | -2 | -1/2 (Δ[HCl])/(Δt) HNO_3 | 6 | -6 | -1/6 (Δ[HNO3])/(Δt) HgS | 1 | -1 | -(Δ[HgS])/(Δt) S | 1 | 1 | (Δ[S])/(Δt) NO | 6 | 6 | 1/6 (Δ[NO])/(Δt) HgCl_2 | 1 | 1 | (Δ[HgCl2])/(Δt) H2O2O | 4 | 4 | 1/4 (Δ[H2O2O])/(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[HCl])/(Δt) = -1/6 (Δ[HNO3])/(Δt) = -(Δ[HgS])/(Δt) = (Δ[S])/(Δt) = 1/6 (Δ[NO])/(Δt) = (Δ[HgCl2])/(Δt) = 1/4 (Δ[H2O2O])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| hydrogen chloride | nitric acid | mercury(II) sulfide | mixed sulfur | nitric oxide | mercuric chloride | H2O2O formula | HCl | HNO_3 | HgS | S | NO | HgCl_2 | H2O2O Hill formula | ClH | HNO_3 | HgS | S | NO | Cl_2Hg | H2O3 name | hydrogen chloride | nitric acid | mercury(II) sulfide | mixed sulfur | nitric oxide | mercuric chloride | IUPAC name | hydrogen chloride | nitric acid | thioxomercury | sulfur | nitric oxide | dichloromercury |