Question

The analgesic paracetamol, has a molar mass of 151.17 g/mol. If 15.0 mg of paracetamol are
combusted in oxygen, 34.97 x 10-3
g of CO2 are produced. If paracetamol consists only of
C,H,N and O, and it is 9.3% N and 5.96% H by mass, what is its molecular formula?

Answer 1

During combustion:
number of moles of paracetamol = \(15\times10^{-3}\over 151.17\)
number of moles of CO2 = \(34.97\times10^{-3}\over {12+16+16}\)

Answer 2

from this, you can find out how much "C" is present in paracetamol

Answer 3

\[N = {9.3\over100}\times 151.17\approx14
\]
Hence, one atom of "N"

Answer 4

similarly, for H:
\[H={5.96\over100}\times 151.17\approx9\]
hence, "9" atoms of H are present

Answer 5

paracetamol:
\(C_nH_9NO_m\)
we have to find "n" and "m"

Answer 6

i'm following along i cant seem to find carbon and oxygen

Answer 7

you can get that from the combustion
nomber of moles of CO2 produced should be equal to the number of "C" atoms
and the "O" atoms can be found from the total molar mass

Answer 8

thats what I tried to show in the first post.
Combustion:
number of moles of paracetamol \(\approx1\times10^{-4}\)
number of moles of CO2 \(\approx0.8\times10^{-3}\)

we take the ratio and we get the carbon atoms to be "8"

Answer 9

thanks can you help me with this one.The anaesthetic propofol has a molar mass of 178.27 g/mol. If 15.0 mg of propofol are combusted in
oxygen, 44.50 mg of CO2 and 13.64 mg of H2O are produced. If propofol consists only of C, H and O,
what is its molecular formula?

Answer 10

follow the same steps and I'll check em for ya

Answer 11

thanks i'll be waiting

Answer 12

the easiest way would be to write an abstract combustion formula