Question

The mass of one atom of an element A is $2.65\times {10}^{-23}$g. Calculate its atomic mass and name the element.

• A. 14.1 g, Nitrogen
• B. 12.2 g, Carbon
• C. 15.69 g, Oxygen
• D. 23 g, Sodium

Answer 1

The correct option is C 15.69 g, Oxygen

The mass of one atom of an element A = $2.65\times {10}^{-23}$g
We know that 1 mole of an atom = $6.023\times {10}^{23}$ atoms
1 mole of an atom = its atomic weight
Mass of one atom of an element = $2.65\times {10}^{-23}$g
Mass of $6.023\times {10}^{23}$ atoms of an element A = $2.65\times {10}^{-23}\times 6.023\times {10}^{23}$g $=15.69g$

Thus the element is oxygen.