Ca3N2 = N2 + Ca

Ca_3N_2 calcium nitride ⟶ N_2 nitrogen + Ca calcium

Balance the chemical equation algebraically: Ca_3N_2 ⟶ N_2 + Ca Add stoichiometric coefficients, c_i, to the reactants and products: c_1 Ca_3N_2 ⟶ c_2 N_2 + c_3 Ca Set the number of atoms in the reactants equal to the number of atoms in the products for Ca and N: Ca: | 3 c_1 = c_3 N: | 2 c_1 = 2 c_2 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 = 3 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | Ca_3N_2 ⟶ N_2 + 3 Ca

⟶ +

calcium nitride ⟶ nitrogen + calcium

Construct the equilibrium constant, K, expression for: Ca_3N_2 ⟶ N_2 + Ca 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: Ca_3N_2 ⟶ N_2 + 3 Ca 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 Ca_3N_2 | 1 | -1 N_2 | 1 | 1 Ca | 3 | 3 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression Ca_3N_2 | 1 | -1 | ([Ca3N2])^(-1) N_2 | 1 | 1 | [N2] Ca | 3 | 3 | ([Ca])^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 = ([Ca3N2])^(-1) [N2] ([Ca])^3 = ([N2] ([Ca])^3)/([Ca3N2])

Construct the rate of reaction expression for: Ca_3N_2 ⟶ N_2 + Ca 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: Ca_3N_2 ⟶ N_2 + 3 Ca 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 Ca_3N_2 | 1 | -1 N_2 | 1 | 1 Ca | 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 Ca_3N_2 | 1 | -1 | -(Δ[Ca3N2])/(Δt) N_2 | 1 | 1 | (Δ[N2])/(Δt) Ca | 3 | 3 | 1/3 (Δ[Ca])/(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[Ca3N2])/(Δt) = (Δ[N2])/(Δt) = 1/3 (Δ[Ca])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| calcium nitride | nitrogen | calcium formula | Ca_3N_2 | N_2 | Ca name | calcium nitride | nitrogen | calcium IUPAC name | calcium azanidylidenecalcium | molecular nitrogen | calcium

| calcium nitride | nitrogen | calcium molar mass | 148.25 g/mol | 28.014 g/mol | 40.078 g/mol phase | | gas (at STP) | solid (at STP) melting point | | -210 °C | 850 °C boiling point | | -195.79 °C | 1484 °C density | 2.63 g/cm^3 | 0.001251 g/cm^3 (at 0 °C) | 1.54 g/cm^3 solubility in water | | insoluble | decomposes surface tension | | 0.0066 N/m | dynamic viscosity | | 1.78×10^-5 Pa s (at 25 °C) | odor | | odorless |