A 1.0 mol sample of which of the following compounds has the greatest mass? A. NO
B. NO2
C. N2O
D. N2O5

(D) is the correct option.

Explanation:

Molar mass of NO = (14+16) g/mol = 30 g/mol

Molar mass of NO₂ = (14+16×2) g/mol = 46 g/mol

Molar mass of N₂O = (14×2+16) g/mol = 44 g/mol

Molar mass of N₂O₅ = (14×2+16×5) g/mol = 108 g/mol

Number of moles = mass/molar mass

mass = n × M, M = molar mass

n = 1 mol in each case

Higher the molar mass, greater is the mass of the compound. The molar mass of N₂O₅ is greatest of all other cases. It will have greatest mass.

14 days is the half-life of phosphorus-32