Input interpretation
FeS_2 (pyrite) + Na_2O_2 (sodium peroxide) ⟶ Na_2SO_4 (sodium sulfate) + Fe_2O_3 (iron(III) oxide) + Na_2O (sodium oxide)
Balanced equation
Balance the chemical equation algebraically: FeS_2 + Na_2O_2 ⟶ Na_2SO_4 + Fe_2O_3 + Na_2O Add stoichiometric coefficients, c_i, to the reactants and products: c_1 FeS_2 + c_2 Na_2O_2 ⟶ c_3 Na_2SO_4 + c_4 Fe_2O_3 + c_5 Na_2O Set the number of atoms in the reactants equal to the number of atoms in the products for Fe, S, Na and O: Fe: | c_1 = 2 c_4 S: | 2 c_1 = c_3 Na: | 2 c_2 = 2 c_3 + 2 c_5 O: | 2 c_2 = 4 c_3 + 3 c_4 + c_5 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_4 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 15 c_3 = 4 c_4 = 1 c_5 = 11 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 FeS_2 + 15 Na_2O_2 ⟶ 4 Na_2SO_4 + Fe_2O_3 + 11 Na_2O
Structures
+ ⟶ + +
Names
pyrite + sodium peroxide ⟶ sodium sulfate + iron(III) oxide + sodium oxide
Equilibrium constant
Construct the equilibrium constant, K, expression for: FeS_2 + Na_2O_2 ⟶ Na_2SO_4 + Fe_2O_3 + Na_2O 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 FeS_2 + 15 Na_2O_2 ⟶ 4 Na_2SO_4 + Fe_2O_3 + 11 Na_2O 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 FeS_2 | 2 | -2 Na_2O_2 | 15 | -15 Na_2SO_4 | 4 | 4 Fe_2O_3 | 1 | 1 Na_2O | 11 | 11 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression FeS_2 | 2 | -2 | ([FeS2])^(-2) Na_2O_2 | 15 | -15 | ([Na2O2])^(-15) Na_2SO_4 | 4 | 4 | ([Na2SO4])^4 Fe_2O_3 | 1 | 1 | [Fe2O3] Na_2O | 11 | 11 | ([Na2O])^11 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 = ([FeS2])^(-2) ([Na2O2])^(-15) ([Na2SO4])^4 [Fe2O3] ([Na2O])^11 = (([Na2SO4])^4 [Fe2O3] ([Na2O])^11)/(([FeS2])^2 ([Na2O2])^15)
Rate of reaction
Construct the rate of reaction expression for: FeS_2 + Na_2O_2 ⟶ Na_2SO_4 + Fe_2O_3 + Na_2O 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 FeS_2 + 15 Na_2O_2 ⟶ 4 Na_2SO_4 + Fe_2O_3 + 11 Na_2O 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 FeS_2 | 2 | -2 Na_2O_2 | 15 | -15 Na_2SO_4 | 4 | 4 Fe_2O_3 | 1 | 1 Na_2O | 11 | 11 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 FeS_2 | 2 | -2 | -1/2 (Δ[FeS2])/(Δt) Na_2O_2 | 15 | -15 | -1/15 (Δ[Na2O2])/(Δt) Na_2SO_4 | 4 | 4 | 1/4 (Δ[Na2SO4])/(Δt) Fe_2O_3 | 1 | 1 | (Δ[Fe2O3])/(Δt) Na_2O | 11 | 11 | 1/11 (Δ[Na2O])/(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[FeS2])/(Δt) = -1/15 (Δ[Na2O2])/(Δt) = 1/4 (Δ[Na2SO4])/(Δt) = (Δ[Fe2O3])/(Δt) = 1/11 (Δ[Na2O])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| pyrite | sodium peroxide | sodium sulfate | iron(III) oxide | sodium oxide formula | FeS_2 | Na_2O_2 | Na_2SO_4 | Fe_2O_3 | Na_2O Hill formula | FeS_2 | Na_2O_2 | Na_2O_4S | Fe_2O_3 | Na_2O name | pyrite | sodium peroxide | sodium sulfate | iron(III) oxide | sodium oxide IUPAC name | bis(sulfanylidene)iron | disodium peroxide | disodium sulfate | | disodium oxygen(-2) anion
Substance properties
| pyrite | sodium peroxide | sodium sulfate | iron(III) oxide | sodium oxide molar mass | 120 g/mol | 77.978 g/mol | 142.04 g/mol | 159.69 g/mol | 61.979 g/mol phase | | solid (at STP) | solid (at STP) | solid (at STP) | melting point | | 660 °C | 884 °C | 1565 °C | boiling point | | | 1429 °C | | density | 4.89 g/cm^3 | 2.805 g/cm^3 | 2.68 g/cm^3 | 5.26 g/cm^3 | 2.27 g/cm^3 solubility in water | | reacts | soluble | insoluble | odor | odorless | | | odorless |
Units