Question

Mass of one atom of an element is $6.64\times {10}^{-23}g$. This is equal to :

• A. $6.64\times {10}^{23}u$
• B. $40.0u$
• C. $\frac{1}{40}u$
• D. $6.64u$

Answer 1

The correct option is B $40.0u$

Mass of 1 atom $=6.664\times {10}^{-23}gm$

1 Gram atom $=$ mass of 1 mole atoms $=6.023\times {10}^{23}\times$ mass of one atom

$=6.023\times 1023\times 6.664\times {10}^{-23}=40.13gm=40u$

Hence, option B is correct.