Question

the mole percentage of oxygen in a mixture of 7 gram of Nitrogen and 8gram of oxygen is
a) 8
b) 16
c) 21
d) 50

Answer 1

The number of moles of nitrogen = Mass of the given substanceMoalr mass = 728 = 0.25The number of moles of oxygen = Mass of the given substanceMoalr mass = 832 = 0.25Total moles = 0.25 + 0.25 = 0.5Mole % of oxygen = Moles of oxygenTotal moles × 100 =0.250.5 × 100 = 50 %