Cl2 + Hg = Hg2Cl2

Cl_2 (chlorine) + Hg (mercury) ⟶ Hg_2Cl_2 (mercury(I) chloride)

Balance the chemical equation algebraically: Cl_2 + Hg ⟶ Hg_2Cl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 Hg ⟶ c_3 Hg_2Cl_2 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and Hg: Cl: | 2 c_1 = 2 c_3 Hg: | 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Cl_2 + 2 Hg ⟶ Hg_2Cl_2

+ ⟶

chlorine + mercury ⟶ mercury(I) chloride

| chlorine | mercury | mercury(I) chloride molecular enthalpy | 0 kJ/mol | 0 kJ/mol | -265 kJ/mol total enthalpy | 0 kJ/mol | 0 kJ/mol | -265 kJ/mol | H_initial = 0 kJ/mol | | H_final = -265 kJ/mol ΔH_rxn^0 | -265 kJ/mol - 0 kJ/mol = -265 kJ/mol (exothermic) | |

| chlorine | mercury | mercury(I) chloride molecular free energy | 0 kJ/mol | 0 kJ/mol | -211 kJ/mol total free energy | 0 kJ/mol | 0 kJ/mol | -211 kJ/mol | G_initial = 0 kJ/mol | | G_final = -211 kJ/mol ΔG_rxn^0 | -211 kJ/mol - 0 kJ/mol = -211 kJ/mol (exergonic) | |

| chlorine | mercury | mercury(I) chloride molecular entropy | 223 J/(mol K) | 76 J/(mol K) | 196 J/(mol K) total entropy | 223 J/(mol K) | 152 J/(mol K) | 196 J/(mol K) | S_initial = 375 J/(mol K) | | S_final = 196 J/(mol K) ΔS_rxn^0 | 196 J/(mol K) - 375 J/(mol K) = -179 J/(mol K) (exoentropic) | |

Construct the equilibrium constant, K, expression for: Cl_2 + Hg ⟶ Hg_2Cl_2 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: Cl_2 + 2 Hg ⟶ Hg_2Cl_2 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 Cl_2 | 1 | -1 Hg | 2 | -2 Hg_2Cl_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2 | 1 | -1 | ([Cl2])^(-1) Hg | 2 | -2 | ([Hg])^(-2) Hg_2Cl_2 | 1 | 1 | [Hg2Cl2] 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 = ([Cl2])^(-1) ([Hg])^(-2) [Hg2Cl2] = ([Hg2Cl2])/([Cl2] ([Hg])^2)

Construct the rate of reaction expression for: Cl_2 + Hg ⟶ Hg_2Cl_2 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: Cl_2 + 2 Hg ⟶ Hg_2Cl_2 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 Cl_2 | 1 | -1 Hg | 2 | -2 Hg_2Cl_2 | 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 Cl_2 | 1 | -1 | -(Δ[Cl2])/(Δt) Hg | 2 | -2 | -1/2 (Δ[Hg])/(Δt) Hg_2Cl_2 | 1 | 1 | (Δ[Hg2Cl2])/(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[Cl2])/(Δt) = -1/2 (Δ[Hg])/(Δt) = (Δ[Hg2Cl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| chlorine | mercury | mercury(I) chloride formula | Cl_2 | Hg | Hg_2Cl_2 Hill formula | Cl_2 | Hg | Cl_2Hg_2 name | chlorine | mercury | mercury(I) chloride IUPAC name | molecular chlorine | mercury | chloromercury

| chlorine | mercury | mercury(I) chloride molar mass | 70.9 g/mol | 200.592 g/mol | 472.08 g/mol phase | gas (at STP) | liquid (at STP) | solid (at STP) melting point | -101 °C | -38.87 °C | 525 °C boiling point | -34 °C | 356.6 °C | 383 °C density | 0.003214 g/cm^3 (at 0 °C) | 13.534 g/cm^3 | 7.16 g/cm^3 solubility in water | | slightly soluble | insoluble surface tension | | 0.47 N/m | dynamic viscosity | | 0.001526 Pa s (at 25 °C) | odor | | odorless |