Question

1. convert 8.43 x 1025 atoms of Fe to moles

2. convert 4.75 x 1024 molecules CO to moles
3. convert 2.43 x 1020 atoms Al to moles

Answer 1

The number of moles of Fe are, 139.9 moles.

The number of moles of CO are, 7.89 moles.

The number of moles of Al are,
`4.04* 10^(-4)` moles.

Explanation :

As we know that 1 mole of substance contains
`6.022* 10^(23)` atoms or molecules.

Part 1:

As,
`6.022* 10^(23)` atoms of Fe present in 1 mole

So,
`8.43* 10^(25)` atoms of Fe present in
`(8.43* 10^(25))/(6.022* 10^(23))* 1=139.9` mole

Thus, the number of moles of Fe are, 139.9 moles.

Part 2:

As,
`6.022* 10^(23)` molecules of CO present in 1 mole

So,
`4.75* 10^(24)` molecules of CO present in
`(4.75* 10^(24))/(6.022* 10^(23))* 1=7.89` mole

Thus, the number of moles of CO are, 7.89 moles.

Part 3:

As,
`6.022* 10^(23)` atoms of Al present in 1 mole

So,
`2.43* 10^(20)` atoms of Al present in
`(2.43* 10^(20))/(6.022* 10^(23))* 1=4.04* 10^(-4)` mole

Thus, the number of moles of Al are,
`4.04* 10^(-4)` moles.