HClO4 = O2 + HCl

HClO_4 perchloric acid ⟶ O_2 oxygen + HCl hydrogen chloride

Balance the chemical equation algebraically: HClO_4 ⟶ O_2 + HCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 HClO_4 ⟶ c_2 O_2 + c_3 HCl Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, H and O: Cl: | c_1 = c_3 H: | c_1 = c_3 O: | 4 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 = 2 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | HClO_4 ⟶ 2 O_2 + HCl

⟶ +

perchloric acid ⟶ oxygen + hydrogen chloride

Construct the equilibrium constant, K, expression for: HClO_4 ⟶ O_2 + HCl 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: HClO_4 ⟶ 2 O_2 + HCl 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 HClO_4 | 1 | -1 O_2 | 2 | 2 HCl | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression HClO_4 | 1 | -1 | ([HClO4])^(-1) O_2 | 2 | 2 | ([O2])^2 HCl | 1 | 1 | [HCl] 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 = ([HClO4])^(-1) ([O2])^2 [HCl] = (([O2])^2 [HCl])/([HClO4])

Construct the rate of reaction expression for: HClO_4 ⟶ O_2 + HCl 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: HClO_4 ⟶ 2 O_2 + HCl 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 HClO_4 | 1 | -1 O_2 | 2 | 2 HCl | 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 HClO_4 | 1 | -1 | -(Δ[HClO4])/(Δt) O_2 | 2 | 2 | 1/2 (Δ[O2])/(Δt) HCl | 1 | 1 | (Δ[HCl])/(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[HClO4])/(Δt) = 1/2 (Δ[O2])/(Δt) = (Δ[HCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| perchloric acid | oxygen | hydrogen chloride formula | HClO_4 | O_2 | HCl Hill formula | ClHO_4 | O_2 | ClH name | perchloric acid | oxygen | hydrogen chloride IUPAC name | perchloric acid | molecular oxygen | hydrogen chloride

| perchloric acid | oxygen | hydrogen chloride molar mass | 100.5 g/mol | 31.998 g/mol | 36.46 g/mol phase | liquid (at STP) | gas (at STP) | gas (at STP) melting point | -112 °C | -218 °C | -114.17 °C boiling point | 90 °C | -183 °C | -85 °C density | 1.77 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 0.00149 g/cm^3 (at 25 °C) solubility in water | very soluble | | miscible surface tension | | 0.01347 N/m | dynamic viscosity | 8×10^-4 Pa s (at 25 °C) | 2.055×10^-5 Pa s (at 25 °C) | odor | odorless | odorless |