Question

A compound contains 15.81%C, 0.66%H and 83.53% I.
If its molar mass is 455.7g/mol, what is its molecular formula

Answer 1

I think you should find the empirical formula first by converting each atom into moles.
% of atom = mass of atom in the compound

mass of atom x (1/molar mass of atom) = # number of moles

then divide each mole by the smallest mole number.. This will give you the pseudo chemical formula of the compound. After you finish this part, I'll tell you what's the next step.

Answer 2

15.81 g of Carbon convert it to moles.
you may need to use the periodic table.
Molar mass of carbon is approx 12 g/mol

15.81 g C (1 mol C /12 g C)
g will get cancelled, so you'll left with 15.81/12 mol of C
Use calc to simplify

Do the same thing for O, and H

Answer 3

for the empirical formula i ended up getting C2HI Now what?

@owlet

Answer 4

what did you get for the oxygen?

Answer 5

where am i geting O from isnt it supposed to be I?
If so i got the following:
C=1.3175
H=0.654761904
I=0.65823483
@owlet @Data_LG2

Answer 6

Oh sorry lol, I thought it is oxygen

So you are right. Empirical formula would be \(\sf C_2HI\)
The last step you have to do it to find the molar mass of this compound using the empirical formula that you found. Then, divide the given molar mass by the molar mass you calculated from the empirical formula. The quotient will serve as the factor to gain the molecular formula.

Answer 7

C = 2 x 12
H = 1
I = 127

add these, what will you get?

Answer 8

I got 152 @Data_LG2

Answer 9

yes, then divide the given molar mass(455.7) to that calculated molar mass(152)

Answer 10

2.998026316 @Data_LG2

Answer 11

yes so 3 will be the factor