H2O + CuO = O2 + H2 + Cu

H_2O water + CuO cupric oxide ⟶ O_2 oxygen + H_2 hydrogen + Cu copper

Balance the chemical equation algebraically: H_2O + CuO ⟶ O_2 + H_2 + Cu Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 CuO ⟶ c_3 O_2 + c_4 H_2 + c_5 Cu Set the number of atoms in the reactants equal to the number of atoms in the products for H, O and Cu: H: | 2 c_1 = 2 c_4 O: | c_1 + c_2 = 2 c_3 Cu: | c_2 = 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_3 = c_2/2 + 1/2 c_4 = 1 c_5 = c_2 The resulting system of equations is still underdetermined, so an additional coefficient must be set arbitrarily. Set c_2 = 1 and solve for the remaining coefficients: c_1 = 1 c_2 = 1 c_3 = 1 c_4 = 1 c_5 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2O + CuO ⟶ O_2 + H_2 + Cu

+ ⟶ + +

water + cupric oxide ⟶ oxygen + hydrogen + copper

| water | cupric oxide | oxygen | hydrogen | copper molecular enthalpy | -285.8 kJ/mol | -157.3 kJ/mol | 0 kJ/mol | 0 kJ/mol | 0 kJ/mol total enthalpy | -285.8 kJ/mol | -157.3 kJ/mol | 0 kJ/mol | 0 kJ/mol | 0 kJ/mol | H_initial = -443.1 kJ/mol | | H_final = 0 kJ/mol | | ΔH_rxn^0 | 0 kJ/mol - -443.1 kJ/mol = 443.1 kJ/mol (endothermic) | | | |

| water | cupric oxide | oxygen | hydrogen | copper molecular entropy | 69.91 J/(mol K) | 43 J/(mol K) | 205 J/(mol K) | 115 J/(mol K) | 33 J/(mol K) total entropy | 69.91 J/(mol K) | 43 J/(mol K) | 205 J/(mol K) | 115 J/(mol K) | 33 J/(mol K) | S_initial = 112.9 J/(mol K) | | S_final = 353 J/(mol K) | | ΔS_rxn^0 | 353 J/(mol K) - 112.9 J/(mol K) = 240.1 J/(mol K) (endoentropic) | | | |

Construct the equilibrium constant, K, expression for: H_2O + CuO ⟶ O_2 + H_2 + Cu 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: H_2O + CuO ⟶ O_2 + H_2 + Cu 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 | 1 | -1 CuO | 1 | -1 O_2 | 1 | 1 H_2 | 1 | 1 Cu | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 1 | -1 | ([H2O])^(-1) CuO | 1 | -1 | ([CuO])^(-1) O_2 | 1 | 1 | [O2] H_2 | 1 | 1 | [H2] Cu | 1 | 1 | [Cu] 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])^(-1) ([CuO])^(-1) [O2] [H2] [Cu] = ([O2] [H2] [Cu])/([H2O] [CuO])

Construct the rate of reaction expression for: H_2O + CuO ⟶ O_2 + H_2 + Cu 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: H_2O + CuO ⟶ O_2 + H_2 + Cu 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 | 1 | -1 CuO | 1 | -1 O_2 | 1 | 1 H_2 | 1 | 1 Cu | 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 H_2O | 1 | -1 | -(Δ[H2O])/(Δt) CuO | 1 | -1 | -(Δ[CuO])/(Δt) O_2 | 1 | 1 | (Δ[O2])/(Δt) H_2 | 1 | 1 | (Δ[H2])/(Δt) Cu | 1 | 1 | (Δ[Cu])/(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[H2O])/(Δt) = -(Δ[CuO])/(Δt) = (Δ[O2])/(Δt) = (Δ[H2])/(Δt) = (Δ[Cu])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| water | cupric oxide | oxygen | hydrogen | copper formula | H_2O | CuO | O_2 | H_2 | Cu name | water | cupric oxide | oxygen | hydrogen | copper IUPAC name | water | | molecular oxygen | molecular hydrogen | copper

| water | cupric oxide | oxygen | hydrogen | copper molar mass | 18.015 g/mol | 79.545 g/mol | 31.998 g/mol | 2.016 g/mol | 63.546 g/mol phase | liquid (at STP) | solid (at STP) | gas (at STP) | gas (at STP) | solid (at STP) melting point | 0 °C | 1326 °C | -218 °C | -259.2 °C | 1083 °C boiling point | 99.9839 °C | 2000 °C | -183 °C | -252.8 °C | 2567 °C density | 1 g/cm^3 | 6.315 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 8.99×10^-5 g/cm^3 (at 0 °C) | 8.96 g/cm^3 solubility in water | | insoluble | | | 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) | 8.9×10^-6 Pa s (at 25 °C) | odor | odorless | | odorless | odorless | odorless