Mass of 2 x 1021 number of atoms of a element is 0.49. What is the mass of 0.5 mole of a b
element?

The mass of 0.5 mole of element ab is 81.67 g.

Explanation:

According to the mole concept, 1 mole of a substance contains . As, the mass of atoms is 0.49 g.

So,

Therefore, mass of 1 mole =

                                            = 163.33 g/mol

Hence, mass of 0.5 mole of ab element is calculated as follows.

= 81.67 g

Therefore, the mass of 0.5 mole of element ab is 81.67 g.

answer: electrons