Question

How many moles are in 45.0 sample of `MgO`?

Answer 1

1.12 moles MgO

Explanation:

Mass of one mole of Magnesium Oxide is 40.3044 g
We can set up conversion factors/ ratios

1 mol MgO = 40.304 g of MgO

1 mol MgO / 40.304 g MgO (a) or 40.340 g MgO / 1 mol MgO (b)

Using the conversion factor (b) we can find number of moles.

45.0 g MgO x ( 1 mol MgO / 40.304 g MgO )

1.1 2 moles MgO