Question

If 20% nitrogen is present in a compound it's minimum molecular weight will be?

Answer 1

Answer: The minimum molecular mass of the compound is 70 grams.

Explanation:

We are given:

A compound having 20 % of nitrogen.

This means that 20 grams of nitrogen will be present in 100 gram of compound.

We know that:

Mass of 1 nitrogen atom = 14 gram

To calculate the minimum molecular weight of compound, there must be 1 nitrogen present. So,

If 20 grams of nitrogen is present in 100 gram of compound.

Then, 14 gram of nitrogen will be present in = $\frac{100g}{20g}\times 14g=70g$ of compound.

Hence, the minimum molecular mass of the compound is 70 grams.

Answer 2

ANSWER

20% Nitrogen by mass means-

100gm of compound has 20g Nitrogen

There should be a minimum of one Nitrogen atom (since Nitrogen atom cannot be present in fractional form)

So for minimum condition →

weight of 1 nitrogen = 20% of the mass of compound.

14g=  20/100  × x (where x is mass of compound)

70g=x = minimum mol. wt.