The empirical formula is the reduced formula, if you will. So whatever the molecular formula is, it is a multiple of the empirical formula. Possible solutions could be C4H10, C6H15, etc.
Only one of those multiples will have a molecular weight of 58.10. To calculate the molecular weight, add the atomic weights of the individual atoms.
One carbon atom has a weight of approximately 12 grams per mole.
One hydrogen atom has a weight of approximately 1 gram per mole.
So the overall weight of a molecule that's CxHy is:
MW = 12x + 1y
In this case:
58.10 = 12x + y
Since we know the empirical formula, we can set up a ratio between x and y:
x/y = 2/5
Now you have two equations with two unknown variables. Solve via substitution.
PS. When cramped for time, it may be faster to skip this and just check by trial and error.
Answers & Comments
Verified answer
The empirical formula is the reduced formula, if you will. So whatever the molecular formula is, it is a multiple of the empirical formula. Possible solutions could be C4H10, C6H15, etc.
Only one of those multiples will have a molecular weight of 58.10. To calculate the molecular weight, add the atomic weights of the individual atoms.
One carbon atom has a weight of approximately 12 grams per mole.
One hydrogen atom has a weight of approximately 1 gram per mole.
So the overall weight of a molecule that's CxHy is:
MW = 12x + 1y
In this case:
58.10 = 12x + y
Since we know the empirical formula, we can set up a ratio between x and y:
x/y = 2/5
Now you have two equations with two unknown variables. Solve via substitution.
PS. When cramped for time, it may be faster to skip this and just check by trial and error.
MW of C2H5 = 12*2+5 = 24+5 = 29
That's half of 58, so the answer must be double:
C4H10 = 4*12+10 = 48+10 = 58