Question

$2.3\times {10}^{22}$ atoms of an element weighs $6.9$ gm. Atomic weight of that element is:

• A. $290$ gm
• B. $180$ gm
• C. $34.4$ gm
• D. $10.4$ gm

Answer 1

The correct option is B $180$ gm

Weight of 1 mole of a substance is equal to atomic weight, and in 1 mole of a substance, there are $6.023\times {10}^{23}$ atoms.

We have weight of $2.3\times {10}^{22}atoms=6.9gm$

Weight of $6.023\times {10}^{23}atoms=6.9\times \frac{6.023\times {10}^{23}}{2.3\times {10}^{22}}=180gm$