Zn + CdSO4 = ZnSO4 + Cd

Zn zinc + CdSO_4 cadmium sulfate ⟶ ZnSO_4 zinc sulfate + Cd cadmium

Balance the chemical equation algebraically: Zn + CdSO_4 ⟶ ZnSO_4 + Cd Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Zn + c_2 CdSO_4 ⟶ c_3 ZnSO_4 + c_4 Cd Set the number of atoms in the reactants equal to the number of atoms in the products for Zn, Cd, O and S: Zn: | c_1 = c_3 Cd: | c_2 = c_4 O: | 4 c_2 = 4 c_3 S: | c_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 = 1 c_3 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Zn + CdSO_4 ⟶ ZnSO_4 + Cd

+ ⟶ +

zinc + cadmium sulfate ⟶ zinc sulfate + cadmium

Construct the equilibrium constant, K, expression for: Zn + CdSO_4 ⟶ ZnSO_4 + Cd 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: Zn + CdSO_4 ⟶ ZnSO_4 + Cd 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 Zn | 1 | -1 CdSO_4 | 1 | -1 ZnSO_4 | 1 | 1 Cd | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Zn | 1 | -1 | ([Zn])^(-1) CdSO_4 | 1 | -1 | ([CdSO4])^(-1) ZnSO_4 | 1 | 1 | [ZnSO4] Cd | 1 | 1 | [Cd] 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 = ([Zn])^(-1) ([CdSO4])^(-1) [ZnSO4] [Cd] = ([ZnSO4] [Cd])/([Zn] [CdSO4])

Construct the rate of reaction expression for: Zn + CdSO_4 ⟶ ZnSO_4 + Cd 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: Zn + CdSO_4 ⟶ ZnSO_4 + Cd 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 Zn | 1 | -1 CdSO_4 | 1 | -1 ZnSO_4 | 1 | 1 Cd | 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 Zn | 1 | -1 | -(Δ[Zn])/(Δt) CdSO_4 | 1 | -1 | -(Δ[CdSO4])/(Δt) ZnSO_4 | 1 | 1 | (Δ[ZnSO4])/(Δt) Cd | 1 | 1 | (Δ[Cd])/(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[Zn])/(Δt) = -(Δ[CdSO4])/(Δt) = (Δ[ZnSO4])/(Δt) = (Δ[Cd])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| zinc | cadmium sulfate | zinc sulfate | cadmium formula | Zn | CdSO_4 | ZnSO_4 | Cd Hill formula | Zn | CdO_4S | O_4SZn | Cd name | zinc | cadmium sulfate | zinc sulfate | cadmium

| zinc | cadmium sulfate | zinc sulfate | cadmium molar mass | 65.38 g/mol | 208.47 g/mol | 161.4 g/mol | 112.414 g/mol phase | solid (at STP) | | | solid (at STP) melting point | 420 °C | | | 320.9 °C boiling point | 907 °C | | | 765 °C density | 7.14 g/cm^3 | | 1.005 g/cm^3 | 8.65 g/cm^3 solubility in water | insoluble | | soluble | insoluble odor | odorless | | odorless | odorless