Question

How many molecules are present in 5 g of `CuSO_4 * 5H_2O`?

Answer 1

In `"copper sulfate pentahydrate"`, well there are `0.020` `mol` of stuff in `5*g`.

Explanation:

`"Moles of"` `CuSO_4*5H_2O` `=` `(5*g)/(249.67*g*mol^-1)=0.020*mol.`

There are thus `0.020*mol` `Cu, and S` atoms. There are `9xx0.020*mol` oxygen atoms, and there are `10xx0.020*mol` hydrogen atoms.

Note that I am dealing with atoms not molecules.