Question

How many moles are in 15.0 g of krypton?

Answer 1

To find the number of moles of a compound given its mass, we can use the Molar Mass of that compound.

In this case, we have 15.0 g of krypton, which is an atom, so we can consult its molar mass from a periodic table.

Consulting it, we get:

`M_(Kr)=83.798g/mol`

The molar mass, the mass and the atomic number are related by the following:

`\begin{gathered} M_(Kr)=(m_(Kr))/(n_(Kr)) \\ n_(Kr)=(m_(Kr))/(M_(Kr)) \end{gathered}`

Substituting the values we have:

`n_(Kr)=(15.0g)/(83.798g/mol)\approx0.179mol`

Thus, there is approximately 0.179 mol in 15.0 g of krypton.