NO2 + Na = NO + NaNO3

NO_2 nitrogen dioxide + Na sodium ⟶ NO nitric oxide + NaNO_3 sodium nitrate

Balance the chemical equation algebraically: NO_2 + Na ⟶ NO + NaNO_3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NO_2 + c_2 Na ⟶ c_3 NO + c_4 NaNO_3 Set the number of atoms in the reactants equal to the number of atoms in the products for N, O and Na: N: | c_1 = c_3 + c_4 O: | 2 c_1 = c_3 + 3 c_4 Na: | 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 = 1 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 NO_2 + Na ⟶ NO + NaNO_3

+ ⟶ +

nitrogen dioxide + sodium ⟶ nitric oxide + sodium nitrate

| nitrogen dioxide | sodium | nitric oxide | sodium nitrate molecular enthalpy | 33.2 kJ/mol | 0 kJ/mol | 91.3 kJ/mol | -467.9 kJ/mol total enthalpy | 66.4 kJ/mol | 0 kJ/mol | 91.3 kJ/mol | -467.9 kJ/mol | H_initial = 66.4 kJ/mol | | H_final = -376.6 kJ/mol | ΔH_rxn^0 | -376.6 kJ/mol - 66.4 kJ/mol = -443 kJ/mol (exothermic) | | |

| nitrogen dioxide | sodium | nitric oxide | sodium nitrate molecular entropy | 240 J/(mol K) | 51 J/(mol K) | 211 J/(mol K) | 116 J/(mol K) total entropy | 480 J/(mol K) | 51 J/(mol K) | 211 J/(mol K) | 116 J/(mol K) | S_initial = 531 J/(mol K) | | S_final = 327 J/(mol K) | ΔS_rxn^0 | 327 J/(mol K) - 531 J/(mol K) = -204 J/(mol K) (exoentropic) | | |

Construct the equilibrium constant, K, expression for: NO_2 + Na ⟶ NO + NaNO_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: 2 NO_2 + Na ⟶ NO + NaNO_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 NO_2 | 2 | -2 Na | 1 | -1 NO | 1 | 1 NaNO_3 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NO_2 | 2 | -2 | ([NO2])^(-2) Na | 1 | -1 | ([Na])^(-1) NO | 1 | 1 | [NO] NaNO_3 | 1 | 1 | [NaNO3] 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 = ([NO2])^(-2) ([Na])^(-1) [NO] [NaNO3] = ([NO] [NaNO3])/(([NO2])^2 [Na])

Construct the rate of reaction expression for: NO_2 + Na ⟶ NO + NaNO_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: 2 NO_2 + Na ⟶ NO + NaNO_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 NO_2 | 2 | -2 Na | 1 | -1 NO | 1 | 1 NaNO_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 NO_2 | 2 | -2 | -1/2 (Δ[NO2])/(Δt) Na | 1 | -1 | -(Δ[Na])/(Δt) NO | 1 | 1 | (Δ[NO])/(Δt) NaNO_3 | 1 | 1 | (Δ[NaNO3])/(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[NO2])/(Δt) = -(Δ[Na])/(Δt) = (Δ[NO])/(Δt) = (Δ[NaNO3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| nitrogen dioxide | sodium | nitric oxide | sodium nitrate formula | NO_2 | Na | NO | NaNO_3 Hill formula | NO_2 | Na | NO | NNaO_3 name | nitrogen dioxide | sodium | nitric oxide | sodium nitrate IUPAC name | Nitrogen dioxide | sodium | nitric oxide | sodium nitrate

| nitrogen dioxide | sodium | nitric oxide | sodium nitrate molar mass | 46.005 g/mol | 22.98976928 g/mol | 30.006 g/mol | 84.994 g/mol phase | gas (at STP) | solid (at STP) | gas (at STP) | solid (at STP) melting point | -11 °C | 97.8 °C | -163.6 °C | 306 °C boiling point | 21 °C | 883 °C | -151.7 °C | density | 0.00188 g/cm^3 (at 25 °C) | 0.968 g/cm^3 | 0.001226 g/cm^3 (at 25 °C) | 2.26 g/cm^3 solubility in water | reacts | decomposes | | soluble dynamic viscosity | 4.02×10^-4 Pa s (at 25 °C) | 1.413×10^-5 Pa s (at 527 °C) | 1.911×10^-5 Pa s (at 25 °C) | 0.003 Pa s (at 250 °C)