HCl + Fe = H2 + FeCl8

HCl hydrogen chloride + Fe iron ⟶ H_2 hydrogen + FeCl8

Balance the chemical equation algebraically: HCl + Fe ⟶ H_2 + FeCl8 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HCl + c_2 Fe ⟶ c_3 H_2 + c_4 FeCl8 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and Fe: Cl: | c_1 = 8 c_4 H: | c_1 = 2 c_3 Fe: | c_2 = 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 8 c_2 = 1 c_3 = 4 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 8 HCl + Fe ⟶ 4 H_2 + FeCl8

+ ⟶ + FeCl8

hydrogen chloride + iron ⟶ hydrogen + FeCl8

Construct the equilibrium constant, K, expression for: HCl + Fe ⟶ H_2 + FeCl8 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: 8 HCl + Fe ⟶ 4 H_2 + FeCl8 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 | 8 | -8 Fe | 1 | -1 H_2 | 4 | 4 FeCl8 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HCl | 8 | -8 | ([HCl])^(-8) Fe | 1 | -1 | ([Fe])^(-1) H_2 | 4 | 4 | ([H2])^4 FeCl8 | 1 | 1 | [FeCl8] 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])^(-8) ([Fe])^(-1) ([H2])^4 [FeCl8] = (([H2])^4 [FeCl8])/(([HCl])^8 [Fe])

Construct the rate of reaction expression for: HCl + Fe ⟶ H_2 + FeCl8 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: 8 HCl + Fe ⟶ 4 H_2 + FeCl8 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 | 8 | -8 Fe | 1 | -1 H_2 | 4 | 4 FeCl8 | 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 | 8 | -8 | -1/8 (Δ[HCl])/(Δt) Fe | 1 | -1 | -(Δ[Fe])/(Δt) H_2 | 4 | 4 | 1/4 (Δ[H2])/(Δt) FeCl8 | 1 | 1 | (Δ[FeCl8])/(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 = -1/8 (Δ[HCl])/(Δt) = -(Δ[Fe])/(Δt) = 1/4 (Δ[H2])/(Δt) = (Δ[FeCl8])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen chloride | iron | hydrogen | FeCl8 formula | HCl | Fe | H_2 | FeCl8 Hill formula | ClH | Fe | H_2 | Cl8Fe name | hydrogen chloride | iron | hydrogen | IUPAC name | hydrogen chloride | iron | molecular hydrogen |

| hydrogen chloride | iron | hydrogen | FeCl8 molar mass | 36.46 g/mol | 55.845 g/mol | 2.016 g/mol | 339.4 g/mol phase | gas (at STP) | solid (at STP) | gas (at STP) | melting point | -114.17 °C | 1535 °C | -259.2 °C | boiling point | -85 °C | 2750 °C | -252.8 °C | density | 0.00149 g/cm^3 (at 25 °C) | 7.874 g/cm^3 | 8.99×10^-5 g/cm^3 (at 0 °C) | solubility in water | miscible | insoluble | | dynamic viscosity | | | 8.9×10^-6 Pa s (at 25 °C) | odor | | | odorless |