NaNO3 + MgCl2 = NaCl + Mg(NO3)2

NaNO_3 sodium nitrate + MgCl_2 magnesium chloride ⟶ NaCl sodium chloride + Mg(NO_3)_2 magnesium nitrate

Balance the chemical equation algebraically: NaNO_3 + MgCl_2 ⟶ NaCl + Mg(NO_3)_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaNO_3 + c_2 MgCl_2 ⟶ c_3 NaCl + c_4 Mg(NO_3)_2 Set the number of atoms in the reactants equal to the number of atoms in the products for N, Na, O, Cl and Mg: N: | c_1 = 2 c_4 Na: | c_1 = c_3 O: | 3 c_1 = 6 c_4 Cl: | 2 c_2 = c_3 Mg: | c_2 = 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 2 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 NaNO_3 + MgCl_2 ⟶ 2 NaCl + Mg(NO_3)_2

+ ⟶ +

sodium nitrate + magnesium chloride ⟶ sodium chloride + magnesium nitrate

| sodium nitrate | magnesium chloride | sodium chloride | magnesium nitrate molecular enthalpy | -467.9 kJ/mol | -641.3 kJ/mol | -411.2 kJ/mol | -790.7 kJ/mol total enthalpy | -935.8 kJ/mol | -641.3 kJ/mol | -822.4 kJ/mol | -790.7 kJ/mol | H_initial = -1577 kJ/mol | | H_final = -1613 kJ/mol | ΔH_rxn^0 | -1613 kJ/mol - -1577 kJ/mol = -36 kJ/mol (exothermic) | | |

| sodium nitrate | magnesium chloride | sodium chloride | magnesium nitrate molecular free energy | -366 kJ/mol | -591.8 kJ/mol | -384.1 kJ/mol | -589.4 kJ/mol total free energy | -732 kJ/mol | -591.8 kJ/mol | -768.2 kJ/mol | -589.4 kJ/mol | G_initial = -1324 kJ/mol | | G_final = -1358 kJ/mol | ΔG_rxn^0 | -1358 kJ/mol - -1324 kJ/mol = -33.8 kJ/mol (exergonic) | | |

Construct the equilibrium constant, K, expression for: NaNO_3 + MgCl_2 ⟶ NaCl + Mg(NO_3)_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: 2 NaNO_3 + MgCl_2 ⟶ 2 NaCl + Mg(NO_3)_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 NaNO_3 | 2 | -2 MgCl_2 | 1 | -1 NaCl | 2 | 2 Mg(NO_3)_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaNO_3 | 2 | -2 | ([NaNO3])^(-2) MgCl_2 | 1 | -1 | ([MgCl2])^(-1) NaCl | 2 | 2 | ([NaCl])^2 Mg(NO_3)_2 | 1 | 1 | [Mg(NO3)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 = ([NaNO3])^(-2) ([MgCl2])^(-1) ([NaCl])^2 [Mg(NO3)2] = (([NaCl])^2 [Mg(NO3)2])/(([NaNO3])^2 [MgCl2])

Construct the rate of reaction expression for: NaNO_3 + MgCl_2 ⟶ NaCl + Mg(NO_3)_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: 2 NaNO_3 + MgCl_2 ⟶ 2 NaCl + Mg(NO_3)_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 NaNO_3 | 2 | -2 MgCl_2 | 1 | -1 NaCl | 2 | 2 Mg(NO_3)_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 NaNO_3 | 2 | -2 | -1/2 (Δ[NaNO3])/(Δt) MgCl_2 | 1 | -1 | -(Δ[MgCl2])/(Δt) NaCl | 2 | 2 | 1/2 (Δ[NaCl])/(Δt) Mg(NO_3)_2 | 1 | 1 | (Δ[Mg(NO3)2])/(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 = -1/2 (Δ[NaNO3])/(Δt) = -(Δ[MgCl2])/(Δt) = 1/2 (Δ[NaCl])/(Δt) = (Δ[Mg(NO3)2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| sodium nitrate | magnesium chloride | sodium chloride | magnesium nitrate formula | NaNO_3 | MgCl_2 | NaCl | Mg(NO_3)_2 Hill formula | NNaO_3 | Cl_2Mg | ClNa | MgN_2O_6 name | sodium nitrate | magnesium chloride | sodium chloride | magnesium nitrate IUPAC name | sodium nitrate | magnesium dichloride | sodium chloride | magnesium dinitrate

| sodium nitrate | magnesium chloride | sodium chloride | magnesium nitrate molar mass | 84.994 g/mol | 95.2 g/mol | 58.44 g/mol | 148.31 g/mol phase | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) melting point | 306 °C | 714 °C | 801 °C | 88.9 °C boiling point | | | 1413 °C | 330 °C density | 2.26 g/cm^3 | 2.32 g/cm^3 | 2.16 g/cm^3 | 1.2051 g/cm^3 solubility in water | soluble | soluble | soluble | dynamic viscosity | 0.003 Pa s (at 250 °C) | | | odor | | | odorless |