Given: NH4ClO4 aqueous solution
Concentration of the solution: 1.0 x 10^-2 mol/L
Assuming: 1 Liter solution
Number of moles of NH4ClO4 = 1.0 x 10^-2 moles
Relative molar amounts:
N: 1/1.0 x 10^-2 = 100
H: 4/1.0 x 10^-2 = 400
Cl: 1/1.0 x 10^-2 = 100
O: 4/1.0 x 10^-2 = 400