Cl2 + Sb = SbCl5

Cl_2 chlorine + Sb gray antimony ⟶ SbCl_5 antimony pentachloride

Balance the chemical equation algebraically: Cl_2 + Sb ⟶ SbCl_5 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Cl_2 + c_2 Sb ⟶ c_3 SbCl_5 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and Sb: Cl: | 2 c_1 = 5 c_3 Sb: | 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 5/2 c_2 = 1 c_3 = 1 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 5 c_2 = 2 c_3 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 5 Cl_2 + 2 Sb ⟶ 2 SbCl_5

+ ⟶

chlorine + gray antimony ⟶ antimony pentachloride

Construct the equilibrium constant, K, expression for: Cl_2 + Sb ⟶ SbCl_5 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: 5 Cl_2 + 2 Sb ⟶ 2 SbCl_5 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 | 5 | -5 Sb | 2 | -2 SbCl_5 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Cl_2 | 5 | -5 | ([Cl2])^(-5) Sb | 2 | -2 | ([Sb])^(-2) SbCl_5 | 2 | 2 | ([SbCl5])^2 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])^(-5) ([Sb])^(-2) ([SbCl5])^2 = ([SbCl5])^2/(([Cl2])^5 ([Sb])^2)

Construct the rate of reaction expression for: Cl_2 + Sb ⟶ SbCl_5 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: 5 Cl_2 + 2 Sb ⟶ 2 SbCl_5 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 | 5 | -5 Sb | 2 | -2 SbCl_5 | 2 | 2 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 | 5 | -5 | -1/5 (Δ[Cl2])/(Δt) Sb | 2 | -2 | -1/2 (Δ[Sb])/(Δt) SbCl_5 | 2 | 2 | 1/2 (Δ[SbCl5])/(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 = -1/5 (Δ[Cl2])/(Δt) = -1/2 (Δ[Sb])/(Δt) = 1/2 (Δ[SbCl5])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| chlorine | gray antimony | antimony pentachloride formula | Cl_2 | Sb | SbCl_5 Hill formula | Cl_2 | Sb | Cl_5Sb name | chlorine | gray antimony | antimony pentachloride IUPAC name | molecular chlorine | antimony | pentachlorostiborane

| chlorine | gray antimony | antimony pentachloride molar mass | 70.9 g/mol | 121.76 g/mol | 299 g/mol phase | gas (at STP) | solid (at STP) | liquid (at STP) melting point | -101 °C | 630 °C | 2.8 °C boiling point | -34 °C | 1587 °C | 92 °C (measured at 3999 Pa) density | 0.003214 g/cm^3 (at 0 °C) | 6.69 g/cm^3 | 2.36 g/cm^3 solubility in water | | | soluble dynamic viscosity | | | 0.00191 Pa s (at 35 °C)