Question

When lead(II) sulfide reacts with oxygen (O2) gas, the products are lead(II) oxide and sulfur dioxide gas.How many grams of lead(II) sulfide are used to produce 129 g of lead(II) oxide?

Answer 1

Moles of PbS make 2 moles of PbO, so there is a 1:1 ratio.

Therefore, however many moles of PbO was produced is how many moles of PbS was used to make that many PbO, and you can find grams from the number of moles.

First thing, find out the moles of PbO.

The molar mass of PbO is 223.1994 grams.

Divide 129 grams by the molar mass to find out the moles.

129 / 223.1994 = 0.57795 moles.

That means 0.57795 moles of PbS was used.

You know that the molar mass of PbS is 239.265, so multiply that by 0.57795 and you get 138.285 grams of PbS.