Input interpretation
H_2O water + O_2 oxygen + FeS ferrous sulfide ⟶ S mixed sulfur + Fe(OH)_3 iron(III) hydroxide
Balanced equation
Balance the chemical equation algebraically: H_2O + O_2 + FeS ⟶ S + Fe(OH)_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 O_2 + c_3 FeS ⟶ c_4 S + c_5 Fe(OH)_3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, Fe and S: H: | 2 c_1 = 3 c_5 O: | c_1 + 2 c_2 = 3 c_5 Fe: | c_3 = c_5 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 4/3 c_4 = 4/3 c_5 = 4/3 Multiply by the least common denominator, 3, to eliminate fractional coefficients: c_1 = 6 c_2 = 3 c_3 = 4 c_4 = 4 c_5 = 4 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 6 H_2O + 3 O_2 + 4 FeS ⟶ 4 S + 4 Fe(OH)_3
Structures
+ + ⟶ +
Names
water + oxygen + ferrous sulfide ⟶ mixed sulfur + iron(III) hydroxide
Equilibrium constant
Construct the equilibrium constant, K, expression for: H_2O + O_2 + FeS ⟶ S + Fe(OH)_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 H_2O + 3 O_2 + 4 FeS ⟶ 4 S + 4 Fe(OH)_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 H_2O | 6 | -6 O_2 | 3 | -3 FeS | 4 | -4 S | 4 | 4 Fe(OH)_3 | 4 | 4 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 6 | -6 | ([H2O])^(-6) O_2 | 3 | -3 | ([O2])^(-3) FeS | 4 | -4 | ([FeS])^(-4) S | 4 | 4 | ([S])^4 Fe(OH)_3 | 4 | 4 | ([Fe(OH)3])^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 = ([H2O])^(-6) ([O2])^(-3) ([FeS])^(-4) ([S])^4 ([Fe(OH)3])^4 = (([S])^4 ([Fe(OH)3])^4)/(([H2O])^6 ([O2])^3 ([FeS])^4)
Rate of reaction
Construct the rate of reaction expression for: H_2O + O_2 + FeS ⟶ S + Fe(OH)_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 H_2O + 3 O_2 + 4 FeS ⟶ 4 S + 4 Fe(OH)_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 H_2O | 6 | -6 O_2 | 3 | -3 FeS | 4 | -4 S | 4 | 4 Fe(OH)_3 | 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 H_2O | 6 | -6 | -1/6 (Δ[H2O])/(Δt) O_2 | 3 | -3 | -1/3 (Δ[O2])/(Δt) FeS | 4 | -4 | -1/4 (Δ[FeS])/(Δt) S | 4 | 4 | 1/4 (Δ[S])/(Δt) Fe(OH)_3 | 4 | 4 | 1/4 (Δ[Fe(OH)3])/(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[H2O])/(Δt) = -1/3 (Δ[O2])/(Δt) = -1/4 (Δ[FeS])/(Δt) = 1/4 (Δ[S])/(Δt) = 1/4 (Δ[Fe(OH)3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| water | oxygen | ferrous sulfide | mixed sulfur | iron(III) hydroxide formula | H_2O | O_2 | FeS | S | Fe(OH)_3 Hill formula | H_2O | O_2 | FeS | S | FeH_3O_3 name | water | oxygen | ferrous sulfide | mixed sulfur | iron(III) hydroxide IUPAC name | water | molecular oxygen | | sulfur | ferric trihydroxide
Substance properties
| water | oxygen | ferrous sulfide | mixed sulfur | iron(III) hydroxide molar mass | 18.015 g/mol | 31.998 g/mol | 87.9 g/mol | 32.06 g/mol | 106.87 g/mol phase | liquid (at STP) | gas (at STP) | solid (at STP) | solid (at STP) | melting point | 0 °C | -218 °C | 1195 °C | 112.8 °C | boiling point | 99.9839 °C | -183 °C | | 444.7 °C | density | 1 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 4.84 g/cm^3 | 2.07 g/cm^3 | solubility in water | | | insoluble | | surface tension | 0.0728 N/m | 0.01347 N/m | | | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 2.055×10^-5 Pa s (at 25 °C) | 0.00343 Pa s (at 1250 °C) | | odor | odorless | odorless | | |
Units