Question

How many atoms of aluminum (Al) are in 6.98 mol of aluminum?​

Answer 1

`\boxed {\boxed {\sf 4.20 *10^(24) \ atoms \ Al }}`

Step-by-step explanation:

To convert from moles to atoms, we must us Avogadro's number: 6.022*10²³. This tells us the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, it is atoms of aluminum.

We can use the number as a fraction.

`(6.022*10^(23) atoms \ Al)/(1 \ mol \ Al)`

Multiply by the given number of moles: 6.98

`6.98 \ mol \ Al *(6.022*10^(23) atoms \ Al)/(1 \ mol \ Al)`

The moles of aluminum will cancel.

`6.98 *(6.022*10^(23) atoms \ Al)/(1 )`

The denominator of 1 can be ignored.

`6.98 * {6.022*10^(23) atoms \ Al}`

Multiply.

`4.203356*10^(24) \ atoms \ Al`

The original measurement of moles has 3 significant figures, so our answer must have the same.

For the number we calculated, that is the hundredth place. The 3 in the thousandth place tells us to leave the 0.

`4.20 *10^(24) \ atoms \ Al`

There are about 4.20*10²⁴ atoms of aluminum in 6.98 moles.