SbCl5 = Cl2 + SbCl3

SbCl_5 antimony pentachloride ⟶ Cl_2 chlorine + SbCl_3 antimony(III) chloride

Balance the chemical equation algebraically: SbCl_5 ⟶ Cl_2 + SbCl_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 SbCl_5 ⟶ c_2 Cl_2 + c_3 SbCl_3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl and Sb: Cl: | 5 c_1 = 2 c_2 + 3 c_3 Sb: | c_1 = 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: | | SbCl_5 ⟶ Cl_2 + SbCl_3

⟶ +

antimony pentachloride ⟶ chlorine + antimony(III) chloride

Construct the equilibrium constant, K, expression for: SbCl_5 ⟶ Cl_2 + SbCl_3 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: SbCl_5 ⟶ Cl_2 + SbCl_3 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 SbCl_5 | 1 | -1 Cl_2 | 1 | 1 SbCl_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression SbCl_5 | 1 | -1 | ([SbCl5])^(-1) Cl_2 | 1 | 1 | [Cl2] SbCl_3 | 1 | 1 | [SbCl3] 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 = ([SbCl5])^(-1) [Cl2] [SbCl3] = ([Cl2] [SbCl3])/([SbCl5])

Construct the rate of reaction expression for: SbCl_5 ⟶ Cl_2 + SbCl_3 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: SbCl_5 ⟶ Cl_2 + SbCl_3 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 SbCl_5 | 1 | -1 Cl_2 | 1 | 1 SbCl_3 | 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 SbCl_5 | 1 | -1 | -(Δ[SbCl5])/(Δt) Cl_2 | 1 | 1 | (Δ[Cl2])/(Δt) SbCl_3 | 1 | 1 | (Δ[SbCl3])/(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[SbCl5])/(Δt) = (Δ[Cl2])/(Δt) = (Δ[SbCl3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| antimony pentachloride | chlorine | antimony(III) chloride formula | SbCl_5 | Cl_2 | SbCl_3 Hill formula | Cl_5Sb | Cl_2 | Cl_3Sb name | antimony pentachloride | chlorine | antimony(III) chloride IUPAC name | pentachlorostiborane | molecular chlorine | trichlorostibane

| antimony pentachloride | chlorine | antimony(III) chloride molar mass | 299 g/mol | 70.9 g/mol | 228.1 g/mol phase | liquid (at STP) | gas (at STP) | solid (at STP) melting point | 2.8 °C | -101 °C | 73.4 °C boiling point | 92 °C (measured at 3999 Pa) | -34 °C | density | 2.36 g/cm^3 | 0.003214 g/cm^3 (at 0 °C) | solubility in water | soluble | | dynamic viscosity | 0.00191 Pa s (at 35 °C) | |