Question

Could someone assist me with this please? An organic compound containing only C, H and F was found to contain 28.2 % by mass carbon and 4.74 % by mass hydrogen. Determine the empirical formula of the compound.

Answer 1

assume you have 100 g of the compound.

convert each (C, H, F,) into moles and compare them.

Answer 2

C: (28.2g/12.011g/mol= 2.35mol)
H: (4.74g/1.008g/mol= 4.70mol)
F: (67.06/ 19g/mol= 3.5mol)

Answer 3

Since they're not whole numbers, do I round?

Answer 4

Hello?

Answer 5

yes, but first divide all by the lowest number.

Answer 6

So
C: (2.35mol/1.008g/mol=2.33 ) ----> 2
H: (4.70mol/1.008g/mol= 4.67) ---->5
F: (3.5mol/ 1.008g/mol= 3.50) ----> 4

Answer 7

?

Answer 8

hm you didn't divide by the lowest/smallest number of moles.

Answer 9

Ah, I guess I didn't! Thanks for catching that!!
C: (2.35mol/ 2.35 mol=2.33 ) ---->1
H: (4.70mol/ 2.35mol= 4.67) ---->2
F: (3.5mol/ 2.35 mol= 3.50) ----> 1.5

Answer 10

so now you wanna multiply them all by the same constant to make all the number integers

Answer 11

So like:
1*2= 2
2*2=4
1.5*2=3

Answer 12

yep, exactly.

Answer 13

Superb, thanks again!!

Answer 14

no problem !