Teach me empirical and molecular formula

Answer 1

Sure! Here's a brief explanation of empirical and molecular formulas:

Empirical Formula:
The empirical formula of a compound shows the simplest whole number ratio of atoms present in the compound. It does not provide information about the actual number of atoms in a molecule, but instead gives the simplest atom ratio. To determine the empirical formula, you need to have the mass percentages or the mass of each element present in the compound.

For example, let's say we have a compound with the following composition by mass: 40% carbon, 6.7% hydrogen, and 53.3% oxygen. To determine the empirical formula, you would first convert these percentages to moles, and then divide each mole value by the smallest mole value to get a whole number ratio. In this case, the empirical formula would be CH2O.

Molecular Formula:
The molecular formula of a compound shows the actual number of each type of atom present in a molecule. It is a multiple of the empirical formula and can be determined if the molecular weight of the compound is known. To determine the molecular formula, you need to know the mass of the compound and compare it to the mass of the empirical formula.

Using the previous example, let's say that the molecular weight of the compound is found to be 60 g/mol. Since we determined the empirical formula to be CH2O, we can now calculate the molecular formula by dividing the molecular weight by the sum of the atomic weights of the elements in the empirical formula. In this case, the molecular formula would be C2H4O2 or (CH2O)2.

I hope this explanation helps! Let me know if you have any other questions.