Zn + FeS = Fe + ZnS

Zn zinc + FeS ferrous sulfide ⟶ Fe iron + ZnS zinc sulfide

Balance the chemical equation algebraically: Zn + FeS ⟶ Fe + ZnS Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Zn + c_2 FeS ⟶ c_3 Fe + c_4 ZnS Set the number of atoms in the reactants equal to the number of atoms in the products for Zn, Fe and S: Zn: | c_1 = c_4 Fe: | c_2 = c_3 S: | 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 1 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Zn + FeS ⟶ Fe + ZnS

+ ⟶ +

zinc + ferrous sulfide ⟶ iron + zinc sulfide

| zinc | ferrous sulfide | iron | zinc sulfide molecular enthalpy | 0 kJ/mol | -100 kJ/mol | 0 kJ/mol | -206 kJ/mol total enthalpy | 0 kJ/mol | -100 kJ/mol | 0 kJ/mol | -206 kJ/mol | H_initial = -100 kJ/mol | | H_final = -206 kJ/mol | ΔH_rxn^0 | -206 kJ/mol - -100 kJ/mol = -106 kJ/mol (exothermic) | | |

| zinc | ferrous sulfide | iron | zinc sulfide molecular entropy | 42 J/(mol K) | 67 J/(mol K) | 27 J/(mol K) | 58 J/(mol K) total entropy | 42 J/(mol K) | 67 J/(mol K) | 27 J/(mol K) | 58 J/(mol K) | S_initial = 109 J/(mol K) | | S_final = 85 J/(mol K) | ΔS_rxn^0 | 85 J/(mol K) - 109 J/(mol K) = -24 J/(mol K) (exoentropic) | | |

Construct the equilibrium constant, K, expression for: Zn + FeS ⟶ Fe + ZnS 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: Zn + FeS ⟶ Fe + ZnS 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 Zn | 1 | -1 FeS | 1 | -1 Fe | 1 | 1 ZnS | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Zn | 1 | -1 | ([Zn])^(-1) FeS | 1 | -1 | ([FeS])^(-1) Fe | 1 | 1 | [Fe] ZnS | 1 | 1 | [ZnS] 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 = ([Zn])^(-1) ([FeS])^(-1) [Fe] [ZnS] = ([Fe] [ZnS])/([Zn] [FeS])

Construct the rate of reaction expression for: Zn + FeS ⟶ Fe + ZnS 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: Zn + FeS ⟶ Fe + ZnS 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 Zn | 1 | -1 FeS | 1 | -1 Fe | 1 | 1 ZnS | 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 Zn | 1 | -1 | -(Δ[Zn])/(Δt) FeS | 1 | -1 | -(Δ[FeS])/(Δt) Fe | 1 | 1 | (Δ[Fe])/(Δt) ZnS | 1 | 1 | (Δ[ZnS])/(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 = -(Δ[Zn])/(Δt) = -(Δ[FeS])/(Δt) = (Δ[Fe])/(Δt) = (Δ[ZnS])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc | ferrous sulfide | iron | zinc sulfide formula | Zn | FeS | Fe | ZnS Hill formula | Zn | FeS | Fe | SZn name | zinc | ferrous sulfide | iron | zinc sulfide IUPAC name | zinc | | iron | thioxozinc

| zinc | ferrous sulfide | iron | zinc sulfide molar mass | 65.38 g/mol | 87.9 g/mol | 55.845 g/mol | 97.44 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) melting point | 420 °C | 1195 °C | 1535 °C | 1064 °C boiling point | 907 °C | | 2750 °C | density | 7.14 g/cm^3 | 4.84 g/cm^3 | 7.874 g/cm^3 | 4.1 g/cm^3 solubility in water | insoluble | insoluble | insoluble | dynamic viscosity | | 0.00343 Pa s (at 1250 °C) | | odor | odorless | | |