This is an oxidation-reduction (redox) reaction:

12 NV + 12 e- → 12 NIV (reduction)

6 O-II - 12 e- → 6 O0 (oxidation)

Cr(NO3)3 is an oxidizing agent, Cr(NO3)3 is a reducing agent.

Word equation

chromium nitrate → oxygen + nitrogen dioxide + chromium(III) oxide

Input interpretation

2 CrN3O9 → 3 O2 + 6 NO2 + Cr2O3

chromium nitrate oxygen nitrogen dioxide chromium(III) oxide

Balanced equation

Balance the chemical equation algebraically:

2 CrN3O9 → 3 O2 + 6 NO2 + Cr2O3

Add stoichiometric coefficients, c, to the reactants and products:

c1 2CrN3O9 → c2 3O2 + c36NO2 + c4Cr2O3

Set the number of atoms in the reactants equal to the number of atoms in the products for Cr, N and O:

Cr: c1 = 2c4

N: 3c1 = c3

O: 9c1 = 2c2 + 2c3 + 3c4

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 c4 = 1 and solve the system of equations for the remaining coefficients:

c1 = 2 c2= 3/2

c3=6 c4=1

Multiply by the least common denominator, 2, to eliminate fractional coefficients:

c1 = 4 c2=3

c3 = 12 c4 = 2

Substitute the coefficients into the chemical reaction to obtain the balanced equation:

Answer:

2 CrN3O9 → 3 O2 + 6 NO2 + Cr2O3