A compound is known to have an empirical formula of CH and a molar mass of 78.11 g/mol. What is its molecular formula?
The molar mass of Carbon (C) is 12.01 g/mol, and the molar mass of Hydrogen (H) is 1.00 g/mol. Adding these togther gives us the molar mass of the empirical formula:
molar mass CH = (12.01 g/mol) + (1.00 g/mol) = 13.01 g/mol
We know that molar mass of the given compound to be 78.11 g/mol; dviding that by the molar mass of the empirical formula gives us a mole ratio:
mole ratio CH = (78.11 g/mol) / (13.01 g/mol) = 6
So for 6 moles of carbon we have 6 moles of hydrogen, or
C6H6, otherwise known as Benzene.
Empericalformula of CH and a molar mass of 78.11
To find the molecular formula:
1. Find the molar mass of EF:
Carbon: 1x12= 12
Hydrogen= 1x1= 1
Molar mass 13
2. Write the molar mass of the actual compound given:
3. Make a proportion of the molar mass: ` `
`(MFM)/(EFM)` = `(78.11)/(13)`` `
4. Multiply the number to the emperical formula
MFM/EFM= 78.11/13= 6
Molecular Formula= C6H6
78.11/13.01= APPROX. 6
Molar Mass / Empirical Formula mass = the factor!
Molar Mass = 78.11 g/moL
Empirical Formula mass = ?
- CH = (12.01) + (1.00 ) = 13.01 g/mol
(78.11 g/moL) / (13.01g/moL EF mass) = 6
'6' is the factor
(CH)6 = C6H6
Molecular Formula = C6H6