Input interpretation
HCl hydrogen chloride + Zn zinc + HP(O)(OH)_2 phosphorous acid ⟶ H_2O water + ZnCl_2 zinc chloride + PH_3 phosphine
Balanced equation
Balance the chemical equation algebraically: HCl + Zn + HP(O)(OH)_2 ⟶ H_2O + ZnCl_2 + PH_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 Zn + c_3 HP(O)(OH)_2 ⟶ c_4 H_2O + c_5 ZnCl_2 + c_6 PH_3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H, Zn, O and P: Cl: | c_1 = 2 c_5 H: | c_1 + 3 c_3 = 2 c_4 + 3 c_6 Zn: | c_2 = c_5 O: | 3 c_3 = c_4 P: | c_3 = 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 6 c_2 = 3 c_3 = 1 c_4 = 3 c_5 = 3 c_6 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 6 HCl + 3 Zn + HP(O)(OH)_2 ⟶ 3 H_2O + 3 ZnCl_2 + PH_3
Structures
+ + ⟶ + +
Names
hydrogen chloride + zinc + phosphorous acid ⟶ water + zinc chloride + phosphine
Reaction thermodynamics
Enthalpy
| hydrogen chloride | zinc | phosphorous acid | water | zinc chloride | phosphine molecular enthalpy | -92.3 kJ/mol | 0 kJ/mol | -964.4 kJ/mol | -285.8 kJ/mol | -415.1 kJ/mol | 5.4 kJ/mol total enthalpy | -553.8 kJ/mol | 0 kJ/mol | -964.4 kJ/mol | -857.5 kJ/mol | -1245 kJ/mol | 5.4 kJ/mol | H_initial = -1518 kJ/mol | | | H_final = -2097 kJ/mol | | ΔH_rxn^0 | -2097 kJ/mol - -1518 kJ/mol = -579.2 kJ/mol (exothermic) | | | | |
Equilibrium constant
Construct the equilibrium constant, K, expression for: HCl + Zn + HP(O)(OH)_2 ⟶ H_2O + ZnCl_2 + PH_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: 6 HCl + 3 Zn + HP(O)(OH)_2 ⟶ 3 H_2O + 3 ZnCl_2 + PH_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 HCl | 6 | -6 Zn | 3 | -3 HP(O)(OH)_2 | 1 | -1 H_2O | 3 | 3 ZnCl_2 | 3 | 3 PH_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 6 | -6 | ([HCl])^(-6) Zn | 3 | -3 | ([Zn])^(-3) HP(O)(OH)_2 | 1 | -1 | ([HP(O)(OH)2])^(-1) H_2O | 3 | 3 | ([H2O])^3 ZnCl_2 | 3 | 3 | ([ZnCl2])^3 PH_3 | 1 | 1 | [PH3] 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])^(-6) ([Zn])^(-3) ([HP(O)(OH)2])^(-1) ([H2O])^3 ([ZnCl2])^3 [PH3] = (([H2O])^3 ([ZnCl2])^3 [PH3])/(([HCl])^6 ([Zn])^3 [HP(O)(OH)2])
Rate of reaction
Construct the rate of reaction expression for: HCl + Zn + HP(O)(OH)_2 ⟶ H_2O + ZnCl_2 + PH_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: 6 HCl + 3 Zn + HP(O)(OH)_2 ⟶ 3 H_2O + 3 ZnCl_2 + PH_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 HCl | 6 | -6 Zn | 3 | -3 HP(O)(OH)_2 | 1 | -1 H_2O | 3 | 3 ZnCl_2 | 3 | 3 PH_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 HCl | 6 | -6 | -1/6 (Δ[HCl])/(Δt) Zn | 3 | -3 | -1/3 (Δ[Zn])/(Δt) HP(O)(OH)_2 | 1 | -1 | -(Δ[HP(O)(OH)2])/(Δt) H_2O | 3 | 3 | 1/3 (Δ[H2O])/(Δt) ZnCl_2 | 3 | 3 | 1/3 (Δ[ZnCl2])/(Δt) PH_3 | 1 | 1 | (Δ[PH3])/(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 = -1/6 (Δ[HCl])/(Δt) = -1/3 (Δ[Zn])/(Δt) = -(Δ[HP(O)(OH)2])/(Δt) = 1/3 (Δ[H2O])/(Δt) = 1/3 (Δ[ZnCl2])/(Δt) = (Δ[PH3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| hydrogen chloride | zinc | phosphorous acid | water | zinc chloride | phosphine formula | HCl | Zn | HP(O)(OH)_2 | H_2O | ZnCl_2 | PH_3 Hill formula | ClH | Zn | H_3O_3P | H_2O | Cl_2Zn | H_3P name | hydrogen chloride | zinc | phosphorous acid | water | zinc chloride | phosphine IUPAC name | hydrogen chloride | zinc | phosphorous acid | water | zinc dichloride | phosphine