explain this chemistry question please (GCSE)

mysterious lady

Find the emperical formula of a compound that is 48.38% carbon, 8.12% hydrogen and 53.5% oxygen by mass. aLSO WOT IS THIS WHOLE THINGS ABOUT THE MOLeS?

A Mole of any element (say oxygen) basically defines the number of particles (atoms/molecules/ions) in 16g of that elemnt (oxygen in this case).
One mole of any substance has got 6.02*10^23 particles of that substance; meaning that one mole of any subtance is its relative or molecular mass expressed in grams.

Coming on to your question:
Recall what empirical formula is- It is the simplest whole number ratio o fthe elemnts in the compound.

Firstly convert the % into grams= C: 48.38g H: 8.12g O:53.5g

Now you have the number of moles of each substance= C: 48.38/12=4.031 H: 8.12/1= 8.12 O: 53.5/16= 3.343

Now you find the mole ratio= C: 4.031/3.343=1.205=~1 H: 8.12/3.343=2.43=~2.5 O: 3.343/3.343=1

So the mole ratio= C :h:

:O = 1:2.5:1
but we want whole numbers= So times everything by 2 giving;
2:5:2 giving C2H5O2

Reply 2

Eternity Forever

I now get the first part of it.

ok, but when you find the mole ratio, why do you divide everything by 3.43? And "1:2.5:1" are these not already whole numbers? Why do you have to multiply them by 2?

Reply 3

Stranded

mysterious lady

I now get the first part of it.

ok, but when you find the mole ratio, why do you divide everything by 3.43? And "1:2.5:1" are these not already whole numbers? Why do you have to multiply them by 2?