Question

Number of molecules in 7.4 gram of ninhydrin

Answer 1

Gram Molecular Mass of Ninhydrin (C₉H₆O₄)
= [(12 × 9) + (1 × 6) + (16 × 4)] gram 
= [108 + 6 + 64] gram
= 178 gram

178 gram of Ninhydrin contains → 1 mole molecules
1 gram of Ninhydrin contains → 1/178 mole molecules
7.4 gram of Ninhydrin contains → 7.4/178 mole molecules

∴ No. of molecules in 7.4 gram of Ninhydrin 
                   = 7.4/178 × 6.023 × 10 ²³ molecules