CuSO4 + KI = K2SO4 + CuI2

CuSO_4 copper(II) sulfate + KI potassium iodide ⟶ K_2SO_4 potassium sulfate + CuI2

Balance the chemical equation algebraically: CuSO_4 + KI ⟶ K_2SO_4 + CuI2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 CuSO_4 + c_2 KI ⟶ c_3 K_2SO_4 + c_4 CuI2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cu, O, S, I and K: Cu: | c_1 = c_4 O: | 4 c_1 = 4 c_3 S: | c_1 = c_3 I: | c_2 = 2 c_4 K: | c_2 = 2 c_3 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 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | CuSO_4 + 2 KI ⟶ K_2SO_4 + CuI2

+ ⟶ + CuI2

copper(II) sulfate + potassium iodide ⟶ potassium sulfate + CuI2

Construct the equilibrium constant, K, expression for: CuSO_4 + KI ⟶ K_2SO_4 + CuI2 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: CuSO_4 + 2 KI ⟶ K_2SO_4 + CuI2 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 CuSO_4 | 1 | -1 KI | 2 | -2 K_2SO_4 | 1 | 1 CuI2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression CuSO_4 | 1 | -1 | ([CuSO4])^(-1) KI | 2 | -2 | ([KI])^(-2) K_2SO_4 | 1 | 1 | [K2SO4] CuI2 | 1 | 1 | [CuI2] 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 = ([CuSO4])^(-1) ([KI])^(-2) [K2SO4] [CuI2] = ([K2SO4] [CuI2])/([CuSO4] ([KI])^2)

Construct the rate of reaction expression for: CuSO_4 + KI ⟶ K_2SO_4 + CuI2 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: CuSO_4 + 2 KI ⟶ K_2SO_4 + CuI2 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 CuSO_4 | 1 | -1 KI | 2 | -2 K_2SO_4 | 1 | 1 CuI2 | 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 CuSO_4 | 1 | -1 | -(Δ[CuSO4])/(Δt) KI | 2 | -2 | -1/2 (Δ[KI])/(Δt) K_2SO_4 | 1 | 1 | (Δ[K2SO4])/(Δt) CuI2 | 1 | 1 | (Δ[CuI2])/(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[CuSO4])/(Δt) = -1/2 (Δ[KI])/(Δt) = (Δ[K2SO4])/(Δt) = (Δ[CuI2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| copper(II) sulfate | potassium iodide | potassium sulfate | CuI2 formula | CuSO_4 | KI | K_2SO_4 | CuI2 Hill formula | CuO_4S | IK | K_2O_4S | CuI2 name | copper(II) sulfate | potassium iodide | potassium sulfate | IUPAC name | copper sulfate | potassium iodide | dipotassium sulfate |

| copper(II) sulfate | potassium iodide | potassium sulfate | CuI2 molar mass | 159.6 g/mol | 166.0028 g/mol | 174.25 g/mol | 317.355 g/mol phase | solid (at STP) | solid (at STP) | | melting point | 200 °C | 681 °C | | boiling point | | 1330 °C | | density | 3.603 g/cm^3 | 3.123 g/cm^3 | | solubility in water | | | soluble | dynamic viscosity | | 0.0010227 Pa s (at 732.9 °C) | |