Cl2O7 = O2 + Cl2

Cl_2O_7 dichlorine heptoxide ⟶ O_2 oxygen + Cl_2 chlorine

Balance the chemical equation algebraically: Cl_2O_7 ⟶ O_2 + Cl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2O_7 ⟶ c_2 O_2 + c_3 Cl_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and O: Cl: | 2 c_1 = 2 c_3 O: | 7 c_1 = 2 c_2 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 = 7/2 c_3 = 1 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 2 c_2 = 7 c_3 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 Cl_2O_7 ⟶ 7 O_2 + 2 Cl_2

⟶ +

dichlorine heptoxide ⟶ oxygen + chlorine

Construct the equilibrium constant, K, expression for: Cl_2O_7 ⟶ O_2 + Cl_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 Cl_2O_7 ⟶ 7 O_2 + 2 Cl_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 Cl_2O_7 | 2 | -2 O_2 | 7 | 7 Cl_2 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2O_7 | 2 | -2 | ([Cl2O7])^(-2) O_2 | 7 | 7 | ([O2])^7 Cl_2 | 2 | 2 | ([Cl2])^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 = ([Cl2O7])^(-2) ([O2])^7 ([Cl2])^2 = (([O2])^7 ([Cl2])^2)/([Cl2O7])^2

Construct the rate of reaction expression for: Cl_2O_7 ⟶ O_2 + Cl_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 Cl_2O_7 ⟶ 7 O_2 + 2 Cl_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 Cl_2O_7 | 2 | -2 O_2 | 7 | 7 Cl_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 Cl_2O_7 | 2 | -2 | -1/2 (Δ[Cl2O7])/(Δt) O_2 | 7 | 7 | 1/7 (Δ[O2])/(Δt) Cl_2 | 2 | 2 | 1/2 (Δ[Cl2])/(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[Cl2O7])/(Δt) = 1/7 (Δ[O2])/(Δt) = 1/2 (Δ[Cl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| dichlorine heptoxide | oxygen | chlorine formula | Cl_2O_7 | O_2 | Cl_2 name | dichlorine heptoxide | oxygen | chlorine IUPAC name | perchloryl perchlorate | molecular oxygen | molecular chlorine

| dichlorine heptoxide | oxygen | chlorine molar mass | 182.9 g/mol | 31.998 g/mol | 70.9 g/mol phase | | gas (at STP) | gas (at STP) melting point | -91.5 °C | -218 °C | -101 °C boiling point | 82 °C | -183 °C | -34 °C density | 1.9 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 0.003214 g/cm^3 (at 0 °C) solubility in water | reacts | | surface tension | | 0.01347 N/m | dynamic viscosity | | 2.055×10^-5 Pa s (at 25 °C) | odor | | odorless |