Question

Help much appreciated!

I know the answer but don't know how to get to it so please show full working, thanks!

Answer 1

Let's find the masses of carbon and hydrogen from the masses of our products

for carbon:

`23.98 g (CO_2) * (12 g (C))/(44g (CO_2))`

mass of carbon = 6.54 gram

for hydrogen:

`4.91 g (H_(2)O) * (1 g (H))/(18 g (H_(2)O))`

mass of hydrogen = 0.27 gram

Total mass of carbon and hydrogen:

Mass of Carbon + Mass of Hydrogen = 6.54 + 0.27 = 6.81 gram

since we had a 10 gram sample, the rest of the mass must be because of Oxygen. so,

Mass of Oxygen:

Mass of compound - Mass of carbon and hydrogen

10 - 6.81 = 3.19 gram Oxygen

Finding number of moles:

Moles of Carbon:

`\displaystyle moles = (given~mass)/(molar~mass) = (6.54~grams)/(12~(grams)/(mole)) = 0.6~moles`

Moles of Oxygen:

`\displaystyle moles = (given~mass)/(molar~mass) = (3.19~grams)/(16~(grams)/(mole)) = 0.2~moles`

Moles of Hydrogen:

`\displaystyle moles = (given~mass)/(molar~mass) = (0.27~grams)/(1~(grams)/(mole)) = 0.3~moles`

Empirical Formula:

Carbon : Hydrogen : Oxygen

0.6 : 0.3 : 0.2

6 : 3 : 2

C₆H₃O₂