Question

How many formula units of CaO are in 32.7 g of CaO?

Answer 1

Answer:

D) 3.51x10²³ formula units

Explanation:

To know this, we need to calculate the molecular mass of CaO. To do that, let's use the atomic mass of each element of this compound.

Ca: 40.08 g/mol;    O: 16 g/mol

With these given AM, let's calculate the molar mass of CaO:

Mm CaO = 40.08 + 16 = 56.08 g/mol

Now that we have the MM of CaO, it's time to determine the moles of CaO:

moles = mass / MM

moles = 32.7 / 56.08 = 0.5831 moles

Finally to get the formula units, we need to use the Avogadro's number which is 6.02x10²³. According to this number, 1 mole of any substance has this number of atoms, molecules or formula units. So, if we have 0.5831 moles, then the formula units will be:

FU = 0.5831 * 6.02x10²³

FU = 3.51x10²³ formula units

Hope this helps