KOH + CrCl3 + KClO4 = H2O + KCl + K2CrO4

KOH potassium hydroxide + CrCl_3 chromic chloride + KClO_4 potassium perchlorate ⟶ H_2O water + KCl potassium chloride + K_2CrO_4 potassium chromate

Balance the chemical equation algebraically: KOH + CrCl_3 + KClO_4 ⟶ H_2O + KCl + K_2CrO_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 KOH + c_2 CrCl_3 + c_3 KClO_4 ⟶ c_4 H_2O + c_5 KCl + c_6 K_2CrO_4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, K, O, Cl and Cr: H: | c_1 = 2 c_4 K: | c_1 + c_3 = c_5 + 2 c_6 O: | c_1 + 4 c_3 = c_4 + 4 c_6 Cl: | 3 c_2 + c_3 = c_5 Cr: | c_2 = c_6 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 40/3 c_2 = 8/3 c_3 = 1 c_4 = 20/3 c_5 = 9 c_6 = 8/3 Multiply by the least common denominator, 3, to eliminate fractional coefficients: c_1 = 40 c_2 = 8 c_3 = 3 c_4 = 20 c_5 = 27 c_6 = 8 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 40 KOH + 8 CrCl_3 + 3 KClO_4 ⟶ 20 H_2O + 27 KCl + 8 K_2CrO_4

+ + ⟶ + +

potassium hydroxide + chromic chloride + potassium perchlorate ⟶ water + potassium chloride + potassium chromate

Construct the equilibrium constant, K, expression for: KOH + CrCl_3 + KClO_4 ⟶ H_2O + KCl + K_2CrO_4 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: 40 KOH + 8 CrCl_3 + 3 KClO_4 ⟶ 20 H_2O + 27 KCl + 8 K_2CrO_4 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 KOH | 40 | -40 CrCl_3 | 8 | -8 KClO_4 | 3 | -3 H_2O | 20 | 20 KCl | 27 | 27 K_2CrO_4 | 8 | 8 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression KOH | 40 | -40 | ([KOH])^(-40) CrCl_3 | 8 | -8 | ([CrCl3])^(-8) KClO_4 | 3 | -3 | ([KClO4])^(-3) H_2O | 20 | 20 | ([H2O])^20 KCl | 27 | 27 | ([KCl])^27 K_2CrO_4 | 8 | 8 | ([K2CrO4])^8 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 = ([KOH])^(-40) ([CrCl3])^(-8) ([KClO4])^(-3) ([H2O])^20 ([KCl])^27 ([K2CrO4])^8 = (([H2O])^20 ([KCl])^27 ([K2CrO4])^8)/(([KOH])^40 ([CrCl3])^8 ([KClO4])^3)

Construct the rate of reaction expression for: KOH + CrCl_3 + KClO_4 ⟶ H_2O + KCl + K_2CrO_4 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: 40 KOH + 8 CrCl_3 + 3 KClO_4 ⟶ 20 H_2O + 27 KCl + 8 K_2CrO_4 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 KOH | 40 | -40 CrCl_3 | 8 | -8 KClO_4 | 3 | -3 H_2O | 20 | 20 KCl | 27 | 27 K_2CrO_4 | 8 | 8 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 KOH | 40 | -40 | -1/40 (Δ[KOH])/(Δt) CrCl_3 | 8 | -8 | -1/8 (Δ[CrCl3])/(Δt) KClO_4 | 3 | -3 | -1/3 (Δ[KClO4])/(Δt) H_2O | 20 | 20 | 1/20 (Δ[H2O])/(Δt) KCl | 27 | 27 | 1/27 (Δ[KCl])/(Δt) K_2CrO_4 | 8 | 8 | 1/8 (Δ[K2CrO4])/(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 = -1/40 (Δ[KOH])/(Δt) = -1/8 (Δ[CrCl3])/(Δt) = -1/3 (Δ[KClO4])/(Δt) = 1/20 (Δ[H2O])/(Δt) = 1/27 (Δ[KCl])/(Δt) = 1/8 (Δ[K2CrO4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| potassium hydroxide | chromic chloride | potassium perchlorate | water | potassium chloride | potassium chromate formula | KOH | CrCl_3 | KClO_4 | H_2O | KCl | K_2CrO_4 Hill formula | HKO | Cl_3Cr | ClKO_4 | H_2O | ClK | CrK_2O_4 name | potassium hydroxide | chromic chloride | potassium perchlorate | water | potassium chloride | potassium chromate IUPAC name | potassium hydroxide | trichlorochromium | potassium perchlorate | water | potassium chloride | dipotassium dioxido-dioxochromium

| potassium hydroxide | chromic chloride | potassium perchlorate | water | potassium chloride | potassium chromate molar mass | 56.105 g/mol | 158.3 g/mol | 138.54 g/mol | 18.015 g/mol | 74.55 g/mol | 194.19 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) | solid (at STP) melting point | 406 °C | 1152 °C | 400 °C | 0 °C | 770 °C | 971 °C boiling point | 1327 °C | | | 99.9839 °C | 1420 °C | density | 2.044 g/cm^3 | 2.87 g/cm^3 | 2.5239 g/cm^3 | 1 g/cm^3 | 1.98 g/cm^3 | 2.73 g/cm^3 solubility in water | soluble | slightly soluble | | | soluble | soluble surface tension | | | | 0.0728 N/m | | dynamic viscosity | 0.001 Pa s (at 550 °C) | | | 8.9×10^-4 Pa s (at 25 °C) | | odor | | | | odorless | odorless | odorless