Question

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?
​

Answer 1

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

Step-by-step explanation:

According to the mole concept, 1 mole of a substance contains
`6.022 * 10^(22)`. As, the mass of
`2 * 10^(21)` atoms is 0.49 g.

So,
`(2 * 10^(21))/(6.022 * 10^(23)) mol = 0.49 g`

`0.003 mol = 0.49 g`

Therefore, mass of 1 mole =
`(0.49)/(0.003)`

= 163.33 g/mol

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

`0.5 mol * 163.33 g/mol`

= 81.67 g

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