What information do you need to calculate the percentage composition of CF4?

You only need the molar masses of Carbon and Florine

Since Carbon's molar mass is 12.011 and Florine's is 18.998 you have all the information

There is one Carbon molecule so the mass of Carbon in CF4 is 12.011

There are four Florine molecules so the mass of Florine is 18.998 x 4 = 75.992

The mass of the molecule of CF4 as a whole is 12.011 + 75.992 = 88.003

Now to calculate percent composition take the mass of each element divided by the mass of the molecule as a whole:

Carbon- 12.011/88.003 = .1365 or 13.65%

Florine- 75.992/88.003 = .8635 or 86.35%What information do you need to calculate the percentage composition of CF4?
Ar(C)= 12,01

Ar(F)= 19,00 that is all





w(C,CF4)= Ar(C) / Mr(CF4)= 0,1365 (or 13,65%)



w(F,CF4)= 4*Ar(F) / Mr(CF4)= 0,8635 (or 86,35%) instead of this you can just do this 100%-13,65%= 86,35%



;)