Question

Question #46beb

Answer 1

`1.51 xx 10^24`

Explanation:

There are 6.022 x `10^23` atoms in a mole ( Avogadro's number)
There are 2 moles of Oxygen in each mole of Carbon Dioxide so

The number of Oxygen atoms is

`1.25 xx 2 xx 6.022 xx 10^23 = 1.51 xx 10^24`

The answer is rounded off to three significant digits because
1.25 moles has only three significant digits.