# If you have 0.250 mol of Al, a) what is the mass of the sample, and b) how many atoms are in the sample?

Sep 4, 2017

$6.75 g$ and $1.51 \cdot {10}^{23}$ $A l$ atoms.

#### Explanation:

a.) What's the mass?

Use the element/compound's molar mass.

$0.250 m o l \cdot \frac{27.0 g}{m o l} = 6.75 g$ of $A l$

b.) How many atoms are in the sample?

$0.250 m o l \cdot \frac{6.023 \cdot {10}^{23} \text{ Al atoms}}{m o l} = 1.51 \cdot {10}^{23}$ $A l$ atoms