Question

Calculate the number of molecules present in 84 g of nitrogen gas

Answer 1

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Answer 2

Given:

Weight of nitrogen gas ($N_{2}$) = 84g

To Find:

The number of molecules in 84g of $N_{2}$.

Solution:

The given numerical can be solved by the following method.

We know that the standard amount of an element contains Avogadro's number of substances.

Avogadro's number = $6.022X10^{23}$

Here,

Molecular weight of nitrogen = 14g

∴ 14g of $N_{2}$ contains $6.022X10^{23}$ molecules

   The number of molecules in 84g of $N_{2}$

=$\frac{84X6.022X10^{23} }{14}$

=$\frac{505.84X10^{23} }{14}$

=$3.61X10^{24}$

Hence, 84g of nitrogen gas contains $3.61X10^{24}$ molecules.