Hg2Cl2 = Hg + HgCl2

Hg_2Cl_2 mercury(I) chloride ⟶ Hg mercury + HgCl_2 mercuric chloride

Balance the chemical equation algebraically: Hg_2Cl_2 ⟶ Hg + HgCl_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Hg_2Cl_2 ⟶ c_2 Hg + c_3 HgCl_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: | 2 c_1 = 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 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Hg_2Cl_2 ⟶ Hg + HgCl_2

⟶ +

mercury(I) chloride ⟶ mercury + mercuric chloride

| mercury(I) chloride | mercury | mercuric chloride molecular enthalpy | -265 kJ/mol | 0 kJ/mol | -224.3 kJ/mol total enthalpy | -265 kJ/mol | 0 kJ/mol | -224.3 kJ/mol | H_initial = -265 kJ/mol | H_final = -224.3 kJ/mol | ΔH_rxn^0 | -224.3 kJ/mol - -265 kJ/mol = 40.7 kJ/mol (endothermic) | |

| mercury(I) chloride | mercury | mercuric chloride molecular free energy | -211 kJ/mol | 0 kJ/mol | -178.6 kJ/mol total free energy | -211 kJ/mol | 0 kJ/mol | -178.6 kJ/mol | G_initial = -211 kJ/mol | G_final = -178.6 kJ/mol | ΔG_rxn^0 | -178.6 kJ/mol - -211 kJ/mol = 32.4 kJ/mol (endergonic) | |

| mercury(I) chloride | mercury | mercuric chloride molecular entropy | 196 J/(mol K) | 76 J/(mol K) | 144 J/(mol K) total entropy | 196 J/(mol K) | 76 J/(mol K) | 144 J/(mol K) | S_initial = 196 J/(mol K) | S_final = 220 J/(mol K) | ΔS_rxn^0 | 220 J/(mol K) - 196 J/(mol K) = 24 J/(mol K) (endoentropic) | |

Construct the equilibrium constant, K, expression for: Hg_2Cl_2 ⟶ Hg + HgCl_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: Hg_2Cl_2 ⟶ Hg + HgCl_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 Hg_2Cl_2 | 1 | -1 Hg | 1 | 1 HgCl_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Hg_2Cl_2 | 1 | -1 | ([Hg2Cl2])^(-1) Hg | 1 | 1 | [Hg] HgCl_2 | 1 | 1 | [HgCl2] 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 = ([Hg2Cl2])^(-1) [Hg] [HgCl2] = ([Hg] [HgCl2])/([Hg2Cl2])

Construct the rate of reaction expression for: Hg_2Cl_2 ⟶ Hg + HgCl_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: Hg_2Cl_2 ⟶ Hg + HgCl_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 Hg_2Cl_2 | 1 | -1 Hg | 1 | 1 HgCl_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 Hg_2Cl_2 | 1 | -1 | -(Δ[Hg2Cl2])/(Δt) Hg | 1 | 1 | (Δ[Hg])/(Δt) HgCl_2 | 1 | 1 | (Δ[HgCl2])/(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[Hg2Cl2])/(Δt) = (Δ[Hg])/(Δt) = (Δ[HgCl2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| mercury(I) chloride | mercury | mercuric chloride formula | Hg_2Cl_2 | Hg | HgCl_2 Hill formula | Cl_2Hg_2 | Hg | Cl_2Hg name | mercury(I) chloride | mercury | mercuric chloride IUPAC name | chloromercury | mercury | dichloromercury

| mercury(I) chloride | mercury | mercuric chloride molar mass | 472.08 g/mol | 200.592 g/mol | 271.49 g/mol phase | solid (at STP) | liquid (at STP) | solid (at STP) melting point | 525 °C | -38.87 °C | 277 °C boiling point | 383 °C | 356.6 °C | 302 °C density | 7.16 g/cm^3 | 13.534 g/cm^3 | 5.44 g/cm^3 solubility in water | insoluble | slightly soluble | surface tension | | 0.47 N/m | dynamic viscosity | | 0.001526 Pa s (at 25 °C) | odor | | odorless | odorless