13 posts • Page 1 of 1
You should divide the number of atoms for each element in the molecular formula by the greatest number that would still leave you with whole numbers. For example the molecular formula for glucose is C6H12O6. Dividing this by 6 would still give you whole numbers: CH2O. This is the empirical formula for glucose.
Molecular formulas are multiples of empirical formulas. In order to get the empirical formula from the molecular formula, you need to reduce the molecular formula to its simplest whole number ratio of atoms. For example, butane has the molecular formula C4H10. We divide by 2 to reduce it and the resulting empirical formula is C2H5.
To go from molecular to empirical formula you divide the subscripts of the molecular formula by the greatest common divisor to get the most reduced form of the formula which is essentially the empirical formula.
It is basically just like simplifying in math. Once you have the molecular formula you simplify using the greatest common number that you can divide by. For example lets say we have C6H12, then you can simplify by dividing what you have by 6 since both numbers are divisible by 6 to get CH6. Don't forget it is also possible for the molecular and empirical formulas to be the same so if you get a molecular formula that seems can not be simplified further, that should also be your empirical formula.
To go from molecular formula to empirical formula you basically divide by the greatest common factor of all the elements. Remember that empirical formulas are ratios of the molecular. For example, C10H20O5 the greatest common factor of 10,20,and 5 is 5. So you divide all those coefficients by 5 and get c2h4o!
Also just as a side note, if visual diagram of the compound is given often it's easier to start by naming the molecular formula, then reduce the numbers to the empirical formula. I assume if one of the elements is only present once the empirical formula would be the same, since you have to only have whole numbers.
When presented with just a molecular formula, the empirical formula can be found by dividing by the greatest whole number that each element is divisible by. However, if the molecular formula is not able to be divided by any number, the empirical formula is known to be the same as the molecular formula.
We can obtain the empirical formula through the molecular formula, by dividing by its highest common denominator. Due to the fact that the molecular is the actual number of atoms, while the empirical is the relative number of atoms.
Who is online
Users browsing this forum: No registered users and 1 guest