H2S + Cd(NO3)2 = HNO3 + CdS

H_2S hydrogen sulfide + Cd(NO3)2 ⟶ HNO_3 nitric acid + CdS cadmium sulfide

Balance the chemical equation algebraically: H_2S + Cd(NO3)2 ⟶ HNO_3 + CdS Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2S + c_2 Cd(NO3)2 ⟶ c_3 HNO_3 + c_4 CdS Set the number of atoms in the reactants equal to the number of atoms in the products for H, S, Cd, N and O: H: | 2 c_1 = c_3 S: | c_1 = c_4 Cd: | c_2 = c_4 N: | 2 c_2 = c_3 O: | 6 c_2 = 3 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 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2S + Cd(NO3)2 ⟶ 2 HNO_3 + CdS

+ Cd(NO3)2 ⟶ +

hydrogen sulfide + Cd(NO3)2 ⟶ nitric acid + cadmium sulfide

Construct the equilibrium constant, K, expression for: H_2S + Cd(NO3)2 ⟶ HNO_3 + CdS 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: H_2S + Cd(NO3)2 ⟶ 2 HNO_3 + CdS 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 H_2S | 1 | -1 Cd(NO3)2 | 1 | -1 HNO_3 | 2 | 2 CdS | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2S | 1 | -1 | ([H2S])^(-1) Cd(NO3)2 | 1 | -1 | ([Cd(NO3)2])^(-1) HNO_3 | 2 | 2 | ([HNO3])^2 CdS | 1 | 1 | [CdS] 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 = ([H2S])^(-1) ([Cd(NO3)2])^(-1) ([HNO3])^2 [CdS] = (([HNO3])^2 [CdS])/([H2S] [Cd(NO3)2])

Construct the rate of reaction expression for: H_2S + Cd(NO3)2 ⟶ HNO_3 + CdS 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: H_2S + Cd(NO3)2 ⟶ 2 HNO_3 + CdS 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 H_2S | 1 | -1 Cd(NO3)2 | 1 | -1 HNO_3 | 2 | 2 CdS | 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 H_2S | 1 | -1 | -(Δ[H2S])/(Δt) Cd(NO3)2 | 1 | -1 | -(Δ[Cd(NO3)2])/(Δt) HNO_3 | 2 | 2 | 1/2 (Δ[HNO3])/(Δt) CdS | 1 | 1 | (Δ[CdS])/(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[H2S])/(Δt) = -(Δ[Cd(NO3)2])/(Δt) = 1/2 (Δ[HNO3])/(Δt) = (Δ[CdS])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| hydrogen sulfide | Cd(NO3)2 | nitric acid | cadmium sulfide formula | H_2S | Cd(NO3)2 | HNO_3 | CdS Hill formula | H_2S | CdN2O6 | HNO_3 | CdS name | hydrogen sulfide | | nitric acid | cadmium sulfide IUPAC name | hydrogen sulfide | | nitric acid | thioxocadmium

| hydrogen sulfide | Cd(NO3)2 | nitric acid | cadmium sulfide molar mass | 34.08 g/mol | 236.42 g/mol | 63.012 g/mol | 144.47 g/mol phase | gas (at STP) | | liquid (at STP) | solid (at STP) melting point | -85 °C | | -41.6 °C | 1400 °C boiling point | -60 °C | | 83 °C | density | 0.001393 g/cm^3 (at 25 °C) | | 1.5129 g/cm^3 | 4.82 g/cm^3 solubility in water | | | miscible | dynamic viscosity | 1.239×10^-5 Pa s (at 25 °C) | | 7.6×10^-4 Pa s (at 25 °C) |