Question

How many moles are contained in 23g He

Answer 1

The property that relates the number of moles of an atom and the mass of the same atom is the atomic weight.

The atomic weight can be consulted in a periodic table.

Consulting one, the atomic weight of He is 4.0026 g/mol.

We can then use rule of three to find the answer:

In 4.0026 g of He, we have 1 mol of He, thus, in 23g of He we have x moles of He:

4.0026 g --- 1 mol

23 g --- x

$\begin{gathered} \frac{4.0026}{23}=\frac{1}{x} \\ x=\frac{23\cdot1}{4.0026} \\ x=5.7462\ldots\approx5.75 \end{gathered}$

Thus, in 23 g of He, there is approximately 5.75 moles.