Al + Na2O2 = Na2O + NaAlO2

Al aluminum + Na_2O_2 sodium peroxide ⟶ Na_2O sodium oxide + AlNaO_2 sodium aluminate

Balance the chemical equation algebraically: Al + Na_2O_2 ⟶ Na_2O + AlNaO_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Al + c_2 Na_2O_2 ⟶ c_3 Na_2O + c_4 AlNaO_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Al, Na and O: Al: | c_1 = c_4 Na: | 2 c_2 = 2 c_3 + c_4 O: | 2 c_2 = c_3 + 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 = 3/2 c_3 = 1 c_4 = 1 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 2 c_2 = 3 c_3 = 2 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 Al + 3 Na_2O_2 ⟶ 2 Na_2O + 2 AlNaO_2

+ ⟶ +

aluminum + sodium peroxide ⟶ sodium oxide + sodium aluminate

Construct the equilibrium constant, K, expression for: Al + Na_2O_2 ⟶ Na_2O + AlNaO_2 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 Al + 3 Na_2O_2 ⟶ 2 Na_2O + 2 AlNaO_2 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 Al | 2 | -2 Na_2O_2 | 3 | -3 Na_2O | 2 | 2 AlNaO_2 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Al | 2 | -2 | ([Al])^(-2) Na_2O_2 | 3 | -3 | ([Na2O2])^(-3) Na_2O | 2 | 2 | ([Na2O])^2 AlNaO_2 | 2 | 2 | ([AlNaO2])^2 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 = ([Al])^(-2) ([Na2O2])^(-3) ([Na2O])^2 ([AlNaO2])^2 = (([Na2O])^2 ([AlNaO2])^2)/(([Al])^2 ([Na2O2])^3)

Construct the rate of reaction expression for: Al + Na_2O_2 ⟶ Na_2O + AlNaO_2 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 Al + 3 Na_2O_2 ⟶ 2 Na_2O + 2 AlNaO_2 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 Al | 2 | -2 Na_2O_2 | 3 | -3 Na_2O | 2 | 2 AlNaO_2 | 2 | 2 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 Al | 2 | -2 | -1/2 (Δ[Al])/(Δt) Na_2O_2 | 3 | -3 | -1/3 (Δ[Na2O2])/(Δt) Na_2O | 2 | 2 | 1/2 (Δ[Na2O])/(Δt) AlNaO_2 | 2 | 2 | 1/2 (Δ[AlNaO2])/(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[Al])/(Δt) = -1/3 (Δ[Na2O2])/(Δt) = 1/2 (Δ[Na2O])/(Δt) = 1/2 (Δ[AlNaO2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| aluminum | sodium peroxide | sodium oxide | sodium aluminate formula | Al | Na_2O_2 | Na_2O | AlNaO_2 name | aluminum | sodium peroxide | sodium oxide | sodium aluminate IUPAC name | aluminum | disodium peroxide | disodium oxygen(-2) anion | sodium oxido-oxo-alumane

| aluminum | sodium peroxide | sodium oxide | sodium aluminate molar mass | 26.9815385 g/mol | 77.978 g/mol | 61.979 g/mol | 81.969 g/mol phase | solid (at STP) | solid (at STP) | | solid (at STP) melting point | 660.4 °C | 660 °C | | 1800 °C boiling point | 2460 °C | | | density | 2.7 g/cm^3 | 2.805 g/cm^3 | 2.27 g/cm^3 | 1.5 g/cm^3 solubility in water | insoluble | reacts | | soluble surface tension | 0.817 N/m | | | dynamic viscosity | 1.5×10^-4 Pa s (at 760 °C) | | | odor | odorless | | |