Question

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

Answer 1

Answer:

$\boxed {\boxed {\sf 4.20 *10^{24} \ atoms \ Al }}$

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.

$\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}$

Multiply by the given number of moles: 6.98

$6.98 \ mol \ Al *\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}$

The moles of aluminum will cancel.

$6.98 *\frac{6.022*10^{23} atoms \ Al}{1 }$

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.