Question

A sample of aluminum foil contains 8.60 × 1023 atoms. What is the mass of the foil?

Answer 1

Answer: The mass of foil is 38.6 grams.

Explanation:

According to mole concept:

$6.022\time 10^{23}$ number of particles are contained in 1 mole of an element.

1 mole of aluminium has a mass of 27 g

We are given:

Number of aluminium atoms = $8.60\times 10^{23}$

To calculate the mass of given number of atoms, we use unitary method:

$6.022\time 10^{23}$ number of particles has a mass of 27 grams

So, $8.60\times 10^{23}$ number of particles has a mass of $\frac{27}{6.022\times 10^{23}}\times 8.60\times 10^{23}=38.6g$

Hence, the mass of foil is 38.6 grams.

Answer 2

8.60*10^23 / 6.02*10^23 (# of atoms in one mole) = 1.43 moles

1.43*26.98 (atomic mass of Al. In other words, this is how much one mole of Al atoms weighs in grams) =
38.54g

38.54g is how much this piece of foil would weigh.