Question

how many formula units are in 5.5 moles of mgo?
? × 10^? formula units of mgo
remember 1 mole = 6.02 × 10^23 formula units
enter the coefficient in the green box and the exponent in the yellow box

Explanation:

Step1: Recall Avogadro's number

1 mole of any substance contains $6.02\times 10^{23}$ formula - units.

Step2: Calculate formula - units in 5.5 moles

We use the conversion factor. If 1 mole = $6.02\times 10^{23}$ formula - units, then for 5.5 moles of MgO, the number of formula - units $n$ is given by $n = 5.5\times(6.02\times 10^{23})$.
\[

$$\begin{align*} n&=(5.5\times6.02)\times 10^{23}\\ & = 33.11\times 10^{23}\\ &=3.311\times 10^{24} \end{align*}$$

\]

Answer:

3.311; 24