KCl + Al = AlCl3 + K

KCl potassium chloride + Al aluminum ⟶ AlCl_3 aluminum chloride + K potassium

Balance the chemical equation algebraically: KCl + Al ⟶ AlCl_3 + K Add stoichiometric coefficients, c_i, to the reactants and products: c_1 KCl + c_2 Al ⟶ c_3 AlCl_3 + c_4 K Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, K and Al: Cl: | c_1 = 3 c_3 K: | c_1 = c_4 Al: | 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 = 3 c_2 = 1 c_3 = 1 c_4 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 3 KCl + Al ⟶ AlCl_3 + 3 K

+ ⟶ +

potassium chloride + aluminum ⟶ aluminum chloride + potassium

| potassium chloride | aluminum | aluminum chloride | potassium molecular entropy | 83 J/(mol K) | 28.3 J/(mol K) | 111 J/(mol K) | 64 J/(mol K) total entropy | 249 J/(mol K) | 28.3 J/(mol K) | 111 J/(mol K) | 192 J/(mol K) | S_initial = 277.3 J/(mol K) | | S_final = 303 J/(mol K) | ΔS_rxn^0 | 303 J/(mol K) - 277.3 J/(mol K) = 25.7 J/(mol K) (endoentropic) | | |

Construct the equilibrium constant, K, expression for: KCl + Al ⟶ AlCl_3 + K 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: 3 KCl + Al ⟶ AlCl_3 + 3 K 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 KCl | 3 | -3 Al | 1 | -1 AlCl_3 | 1 | 1 K | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression KCl | 3 | -3 | ([KCl])^(-3) Al | 1 | -1 | ([Al])^(-1) AlCl_3 | 1 | 1 | [AlCl3] K | 3 | 3 | ([K])^3 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 = ([KCl])^(-3) ([Al])^(-1) [AlCl3] ([K])^3 = ([AlCl3] ([K])^3)/(([KCl])^3 [Al])

Construct the rate of reaction expression for: KCl + Al ⟶ AlCl_3 + K 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: 3 KCl + Al ⟶ AlCl_3 + 3 K 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 KCl | 3 | -3 Al | 1 | -1 AlCl_3 | 1 | 1 K | 3 | 3 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 KCl | 3 | -3 | -1/3 (Δ[KCl])/(Δt) Al | 1 | -1 | -(Δ[Al])/(Δt) AlCl_3 | 1 | 1 | (Δ[AlCl3])/(Δt) K | 3 | 3 | 1/3 (Δ[K])/(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 = -1/3 (Δ[KCl])/(Δt) = -(Δ[Al])/(Δt) = (Δ[AlCl3])/(Δt) = 1/3 (Δ[K])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| potassium chloride | aluminum | aluminum chloride | potassium formula | KCl | Al | AlCl_3 | K Hill formula | ClK | Al | AlCl_3 | K name | potassium chloride | aluminum | aluminum chloride | potassium IUPAC name | potassium chloride | aluminum | trichloroalumane | potassium

| potassium chloride | aluminum | aluminum chloride | potassium molar mass | 74.55 g/mol | 26.9815385 g/mol | 133.3 g/mol | 39.0983 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) melting point | 770 °C | 660.4 °C | 190 °C | 64 °C boiling point | 1420 °C | 2460 °C | | 760 °C density | 1.98 g/cm^3 | 2.7 g/cm^3 | | 0.86 g/cm^3 solubility in water | soluble | insoluble | | reacts surface tension | | 0.817 N/m | | dynamic viscosity | | 1.5×10^-4 Pa s (at 760 °C) | | odor | odorless | odorless | |