Question

What is the mass of oxygen in 250 g of sulfuric acid `H_2SO_4`?

Answer 1

This amount of `H_2SO_4` would contain `10.2` moles of oxygen which is 163.1 grams.

Explanation:

First, you must determine the number of moles of the compound. This will enable you to find how many moles of the particular element would be present, and you can convert this to mass.

Moles of `H_2SO_4` (molar mass = 98.1 g):

`250g:- 98.1 g/"mol"= 2.59` mol

In each molecule of `H_2SO_4` there are 4 oxygen atoms, so 2.59 mol of `H_2SO_4` would contain `2.59 xx 4 = 10.2` mol of O atoms.

Since each mol of O atoms has a mass of 16.0 g, the total mass of oxygen would be

`10.2"mol" xx 16.0g/"mol" = 163.1 g`