What is the empirical formula or 80%Carbon and 20%Hydrogen by mass?

Answer 1

Assume you have 100g of material

80g = carbon, 20 g = hydrogen

moles carbon = 80g * mole/12g = 6.667 moles

moles hydrogen = 20 g * mole/1g = 20 moles

divide both by 6.667

6.667/6.667 = 1 C

20/6.667 = 3 H

The empirical formula is CH3

Answer 2

Okay, this is easy:

You have a hydrocarbon, most likely an alkane, which has the generic formula C(n)H(2n+2):

To solve this, you know that the mass of carbon in the molecule is four times that of the hydrogen, so:

12n = 4(2n+2)

12n = 8n + 8

4n = 8, thus n = 2

So what you have is ethane, C2H6, with an empirical formula of CH3.

2*12 = 24 = 4*6*1

QED.

BTW -- the first two responders have got it wrong -- both give you formulas with a mass ratio of 3/1, not 4/1.

Answer 3

Since a carbon atom has about 12 times the mass of a hydrogen atom, and the mass ratio is 4:1, this means that there must be three times as many hydrogens as carbons. The Emperical formula is CH4.

Answer 4

Carbon | Hydrogen 80% | 20% 12 | a million Molar mass 80/12 = 6.sixty seven | 20/a million = 20 Divide the two by technique of the smaller extensive style 6.sixty seven/6.sixty seven = a million | 20/6.sixty seven = in basic terms approximately 3 the ratio then is a million C for 3 H a) the emperical formula is CH3 b) CH3 has molecular mass of 15, as a manner to get the molecular mass to 30, we ought to consistently multiply by technique of two, which will supply us C2H6, this is the answer to this section. c) 2C2H6 + 7O2 ? 4CO2 + 6H2O

Answer 5

80/12 = 20/3 (ratio of carbon / carbon atomic weight)

20 / 1 = 20 (ratio of hydrogen / hydrogen atomic weight)

C : H ratio = 20/3 : 20 = 20 : 60

empirical formula C20 H60