Question

Question #bb58b

Answer 1

`1.32\times10^{22}" formula units of CaO"`. Note that #"CaO"-does not form discrete molecules so we talk in terms of formula units. Unfortunately the question itself misleads by using "molecules".

Explanation:

First you need the molar mass. `"CaO"` has one atom of `"Ca (atomic mass 40.08)"` and one atom of `"O (atomic mass 16.00)"`. So we add the two atoms:

`40.08+16.00=56.08" g/mol"`

Now divide the mass by the molar mass and multiply by Avogrado's Number:

`{1.23" g"}/{{56.08" g"}/"mol"}\times{6.022\times10^{23}" formula units"}/"mol"`
`=1.32\times10^{22}" formula units"`