H2SO4 + O2 + Cu2Te = H2O + Te + Cu2SO4

H_2SO_4 sulfuric acid + O_2 oxygen + Cu_2Te copper(I) telluride ⟶ H_2O water + Te tellurium + Cu2SO4

Balance the chemical equation algebraically: H_2SO_4 + O_2 + Cu_2Te ⟶ H_2O + Te + Cu2SO4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2SO_4 + c_2 O_2 + c_3 Cu_2Te ⟶ c_4 H_2O + c_5 Te + c_6 Cu2SO4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, S, Cu and Te: H: | 2 c_1 = 2 c_4 O: | 4 c_1 + 2 c_2 = c_4 + 4 c_6 S: | c_1 = c_6 Cu: | 2 c_3 = 2 c_6 Te: | c_3 = 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 2 c_4 = 2 c_5 = 2 c_6 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 H_2SO_4 + O_2 + 2 Cu_2Te ⟶ 2 H_2O + 2 Te + 2 Cu2SO4

+ + ⟶ + + Cu2SO4

sulfuric acid + oxygen + copper(I) telluride ⟶ water + tellurium + Cu2SO4

Construct the equilibrium constant, K, expression for: H_2SO_4 + O_2 + Cu_2Te ⟶ H_2O + Te + Cu2SO4 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 H_2SO_4 + O_2 + 2 Cu_2Te ⟶ 2 H_2O + 2 Te + 2 Cu2SO4 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_2SO_4 | 2 | -2 O_2 | 1 | -1 Cu_2Te | 2 | -2 H_2O | 2 | 2 Te | 2 | 2 Cu2SO4 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2SO_4 | 2 | -2 | ([H2SO4])^(-2) O_2 | 1 | -1 | ([O2])^(-1) Cu_2Te | 2 | -2 | ([Cu2Te])^(-2) H_2O | 2 | 2 | ([H2O])^2 Te | 2 | 2 | ([Te])^2 Cu2SO4 | 2 | 2 | ([Cu2SO4])^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 = ([H2SO4])^(-2) ([O2])^(-1) ([Cu2Te])^(-2) ([H2O])^2 ([Te])^2 ([Cu2SO4])^2 = (([H2O])^2 ([Te])^2 ([Cu2SO4])^2)/(([H2SO4])^2 [O2] ([Cu2Te])^2)

Construct the rate of reaction expression for: H_2SO_4 + O_2 + Cu_2Te ⟶ H_2O + Te + Cu2SO4 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 H_2SO_4 + O_2 + 2 Cu_2Te ⟶ 2 H_2O + 2 Te + 2 Cu2SO4 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_2SO_4 | 2 | -2 O_2 | 1 | -1 Cu_2Te | 2 | -2 H_2O | 2 | 2 Te | 2 | 2 Cu2SO4 | 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 H_2SO_4 | 2 | -2 | -1/2 (Δ[H2SO4])/(Δt) O_2 | 1 | -1 | -(Δ[O2])/(Δt) Cu_2Te | 2 | -2 | -1/2 (Δ[Cu2Te])/(Δt) H_2O | 2 | 2 | 1/2 (Δ[H2O])/(Δt) Te | 2 | 2 | 1/2 (Δ[Te])/(Δt) Cu2SO4 | 2 | 2 | 1/2 (Δ[Cu2SO4])/(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[H2SO4])/(Δt) = -(Δ[O2])/(Δt) = -1/2 (Δ[Cu2Te])/(Δt) = 1/2 (Δ[H2O])/(Δt) = 1/2 (Δ[Te])/(Δt) = 1/2 (Δ[Cu2SO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sulfuric acid | oxygen | copper(I) telluride | water | tellurium | Cu2SO4 formula | H_2SO_4 | O_2 | Cu_2Te | H_2O | Te | Cu2SO4 Hill formula | H_2O_4S | O_2 | Cu_2Te | H_2O | Te | Cu2O4S name | sulfuric acid | oxygen | copper(I) telluride | water | tellurium | IUPAC name | sulfuric acid | molecular oxygen | copper; tellurium | water | tellurium |

| sulfuric acid | oxygen | copper(I) telluride | water | tellurium | Cu2SO4 molar mass | 98.07 g/mol | 31.998 g/mol | 254.69 g/mol | 18.015 g/mol | 127.6 g/mol | 223.15 g/mol phase | liquid (at STP) | gas (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) | melting point | 10.371 °C | -218 °C | 1125 °C | 0 °C | 450 °C | boiling point | 279.6 °C | -183 °C | | 99.9839 °C | 990 °C | density | 1.8305 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 4.6 g/cm^3 | 1 g/cm^3 | 6.24 g/cm^3 | solubility in water | very soluble | | | | insoluble | surface tension | 0.0735 N/m | 0.01347 N/m | | 0.0728 N/m | | dynamic viscosity | 0.021 Pa s (at 25 °C) | 2.055×10^-5 Pa s (at 25 °C) | | 8.9×10^-4 Pa s (at 25 °C) | | odor | odorless | odorless | | odorless | |