# How many moles are in 550.0 g of lead(II) sulfate?

Mar 6, 2017

${\text{1.814 moles PbSO}}_{4}$

#### Explanation:

You can go from moles of a given substance to grams or vice versa by using the molar mass of said substance.

The molar mass tells you the mass of $1$ mole of a given substance

$\text{molar mass" = "mass in grams"/"1 mole of substance}$

In your case, lead(II) sulfate, ${\text{PbSO}}_{4}$, has a molar mass of ${\text{303.2626 g mol}}^{- 1}$, which means that every mole of lead(II) sulfate has a mass of $\text{303.2626 g}$.

To convert from grams to moles, set up the molar mass as a conversion factor with the mass of $1$ mole as the denominator

$\text{1 mole PbSO"_4/"303.2626 g}$

You will have

$550.0 \textcolor{red}{\cancel{\textcolor{b l a c k}{{\text{g"))) * "1 mole PbSO"_4/(303.2626color(red)(cancel(color(black)("g")))) = color(darkgreen)(ul(color(black)("1.814 moles PbSO}}_{4}}}}$

The answer is rounded to four sig figs.