N2O5 = O2 + NO

N_2O_5 dinitrogen pentoxide ⟶ O_2 oxygen + NO nitric oxide

Balance the chemical equation algebraically: N_2O_5 ⟶ O_2 + NO Add stoichiometric coefficients, c_i, to the reactants and products: c_1 N_2O_5 ⟶ c_2 O_2 + c_3 NO Set the number of atoms in the reactants equal to the number of atoms in the products for N and O: N: | 2 c_1 = c_3 O: | 5 c_1 = 2 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_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 3/2 c_3 = 2 Multiply by the least common denominator, 2, to eliminate fractional coefficients: c_1 = 2 c_2 = 3 c_3 = 4 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 N_2O_5 ⟶ 3 O_2 + 4 NO

⟶ +

dinitrogen pentoxide ⟶ oxygen + nitric oxide

| dinitrogen pentoxide | oxygen | nitric oxide molecular enthalpy | -43.1 kJ/mol | 0 kJ/mol | 91.3 kJ/mol total enthalpy | -86.2 kJ/mol | 0 kJ/mol | 365.2 kJ/mol | H_initial = -86.2 kJ/mol | H_final = 365.2 kJ/mol | ΔH_rxn^0 | 365.2 kJ/mol - -86.2 kJ/mol = 451.4 kJ/mol (endothermic) | |

| dinitrogen pentoxide | oxygen | nitric oxide molecular free energy | 113.9 kJ/mol | 231.7 kJ/mol | 87.6 kJ/mol total free energy | 227.8 kJ/mol | 695.1 kJ/mol | 350.4 kJ/mol | G_initial = 227.8 kJ/mol | G_final = 1046 kJ/mol | ΔG_rxn^0 | 1046 kJ/mol - 227.8 kJ/mol = 817.7 kJ/mol (endergonic) | |

| dinitrogen pentoxide | oxygen | nitric oxide molecular entropy | 178 J/(mol K) | 205 J/(mol K) | 211 J/(mol K) total entropy | 356 J/(mol K) | 615 J/(mol K) | 844 J/(mol K) | S_initial = 356 J/(mol K) | S_final = 1459 J/(mol K) | ΔS_rxn^0 | 1459 J/(mol K) - 356 J/(mol K) = 1103 J/(mol K) (endoentropic) | |

Construct the equilibrium constant, K, expression for: N_2O_5 ⟶ O_2 + NO 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 N_2O_5 ⟶ 3 O_2 + 4 NO 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 N_2O_5 | 2 | -2 O_2 | 3 | 3 NO | 4 | 4 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression N_2O_5 | 2 | -2 | ([N2O5])^(-2) O_2 | 3 | 3 | ([O2])^3 NO | 4 | 4 | ([NO])^4 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 = ([N2O5])^(-2) ([O2])^3 ([NO])^4 = (([O2])^3 ([NO])^4)/([N2O5])^2

Construct the rate of reaction expression for: N_2O_5 ⟶ O_2 + NO 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 N_2O_5 ⟶ 3 O_2 + 4 NO 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 N_2O_5 | 2 | -2 O_2 | 3 | 3 NO | 4 | 4 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 N_2O_5 | 2 | -2 | -1/2 (Δ[N2O5])/(Δt) O_2 | 3 | 3 | 1/3 (Δ[O2])/(Δt) NO | 4 | 4 | 1/4 (Δ[NO])/(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[N2O5])/(Δt) = 1/3 (Δ[O2])/(Δt) = 1/4 (Δ[NO])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| dinitrogen pentoxide | oxygen | nitric oxide formula | N_2O_5 | O_2 | NO name | dinitrogen pentoxide | oxygen | nitric oxide IUPAC name | nitro nitrate | molecular oxygen | nitric oxide

| dinitrogen pentoxide | oxygen | nitric oxide molar mass | 108.01 g/mol | 31.998 g/mol | 30.006 g/mol phase | solid (at STP) | gas (at STP) | gas (at STP) melting point | 30 °C | -218 °C | -163.6 °C boiling point | 47 °C | -183 °C | -151.7 °C density | 2.05 g/cm^3 | 0.001429 g/cm^3 (at 0 °C) | 0.001226 g/cm^3 (at 25 °C) surface tension | | 0.01347 N/m | dynamic viscosity | | 2.055×10^-5 Pa s (at 25 °C) | 1.911×10^-5 Pa s (at 25 °C) odor | | odorless |