A - 7g N 2
B - 2g H 2
C - 16g NO 2
D - 16g O 2
Answer
B - 2g H 2
Explanation:
Number of moles = Given mass of substance / Molecular mass of substance
n = m / M
7g N 2 → 7 / 28 = 0.25 moles of molecules
2g H 2 → 2 / 2 = 1 mole of molecules
16g NO 2 → 16 / 46 = 0.347 moles of molecules
16g O 2 → 16 / 32 = 0.5 moles of molecules
Thus 2g H 2 has the most number of molecules.