Question

A compound has 20% of nitrogen by weight. If
one molecule of the compound contains two
nitrogen atoms, the molecular weight of the
compound is
1) 35 2) 70 3) 140 4) 280​

Answer 1

Answer:

Given, 1 molecule of the compound contains 2 nitrogen atoms.

So, 1 mol of compound will have 2 mol of nitrogen atoms =2×14= 28 g of nitrogen.

However, the compound contains 20% of nitrogen by weight.

Therefore, the weight of the compound corresponding to 28 g of nitrogen is =

20

100×28

=140 g.

Hence, the molecular weight of the compound is 140 g/mol.