Input interpretation
MgCl_2 magnesium chloride + K_2CO_3 pearl ash ⟶ KCl potassium chloride + MgCO_3 magnesium carbonate
Balanced equation
Balance the chemical equation algebraically: MgCl_2 + K_2CO_3 ⟶ KCl + MgCO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 MgCl_2 + c_2 K_2CO_3 ⟶ c_3 KCl + c_4 MgCO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for Cl, Mg, C, K and O: Cl: | 2 c_1 = c_3 Mg: | c_1 = c_4 C: | c_2 = c_4 K: | 2 c_2 = c_3 O: | 3 c_2 = 3 c_4 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 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | MgCl_2 + K_2CO_3 ⟶ 2 KCl + MgCO_3
Structures
+ ⟶ +
Names
magnesium chloride + pearl ash ⟶ potassium chloride + magnesium carbonate
Equilibrium constant
Construct the equilibrium constant, K, expression for: MgCl_2 + K_2CO_3 ⟶ KCl + MgCO_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: MgCl_2 + K_2CO_3 ⟶ 2 KCl + MgCO_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 MgCl_2 | 1 | -1 K_2CO_3 | 1 | -1 KCl | 2 | 2 MgCO_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression MgCl_2 | 1 | -1 | ([MgCl2])^(-1) K_2CO_3 | 1 | -1 | ([K2CO3])^(-1) KCl | 2 | 2 | ([KCl])^2 MgCO_3 | 1 | 1 | [MgCO3] 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 = ([MgCl2])^(-1) ([K2CO3])^(-1) ([KCl])^2 [MgCO3] = (([KCl])^2 [MgCO3])/([MgCl2] [K2CO3])
Rate of reaction
Construct the rate of reaction expression for: MgCl_2 + K_2CO_3 ⟶ KCl + MgCO_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: MgCl_2 + K_2CO_3 ⟶ 2 KCl + MgCO_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 MgCl_2 | 1 | -1 K_2CO_3 | 1 | -1 KCl | 2 | 2 MgCO_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 MgCl_2 | 1 | -1 | -(Δ[MgCl2])/(Δt) K_2CO_3 | 1 | -1 | -(Δ[K2CO3])/(Δt) KCl | 2 | 2 | 1/2 (Δ[KCl])/(Δt) MgCO_3 | 1 | 1 | (Δ[MgCO3])/(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[MgCl2])/(Δt) = -(Δ[K2CO3])/(Δt) = 1/2 (Δ[KCl])/(Δt) = (Δ[MgCO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| magnesium chloride | pearl ash | potassium chloride | magnesium carbonate formula | MgCl_2 | K_2CO_3 | KCl | MgCO_3 Hill formula | Cl_2Mg | CK_2O_3 | ClK | CMgO_3 name | magnesium chloride | pearl ash | potassium chloride | magnesium carbonate IUPAC name | magnesium dichloride | dipotassium carbonate | potassium chloride | magnesium carbonate
Substance properties
| magnesium chloride | pearl ash | potassium chloride | magnesium carbonate molar mass | 95.2 g/mol | 138.2 g/mol | 74.55 g/mol | 84.313 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 714 °C | 891 °C | 770 °C | boiling point | | | 1420 °C | density | 2.32 g/cm^3 | 2.43 g/cm^3 | 1.98 g/cm^3 | solubility in water | soluble | soluble | soluble | odor | | | odorless |
Units