A sample contains 0.500 mol of aluminum. What is the mass of aluminum in the sample (in grams)?

Explanation:

To convert from moles to grams we must use the molar mass, which can be found on the Periodic Table.

Use this number as a fraction.

Multiply by the given number of moles.

The moles of aluminum will cancel.

The original number of moles, 0.500, has 3 significant figures, so our answer must have the same.

For the number we calculated, that is the tenth place. The 9 in the hundredth place tells us to round the 4 to a 5.

There are about 13.5 grams of aluminum in 0.500 moles.

13.5 g Al

Explanation:

Recall that to go from moles to mass, you multiply the amount in moles by the molar mass of the substance.

0.500 mol Al = 13.491 g Al --> 13.5 g Al (3 sig figs)

14 days is the half-life of phosphorus-32