[lha08]

Does anyone know how i can differentiate a strong acid from a weak acid and likewise for a strong base from a weak base based on their chemical formula?

[nj_bartel]

That actually takes a fair bit of chemistry knowledge - you need to be able to

1) Produce the structure of the molecule from the formula
2) Find the most acidic protons in the molecule by looking at the stability of the individual conjugate bases (more stable conjugate base, more acidic proton)
3) Compare the stability of the most stable conjugate base with the stability of various conjugate bases of other strong acids

What you're looking for in a stable conjugate base is a structure that

1) Allows large delocalization of the negative charge

and/or

2) Is very content holding the negative charge (more electronegative atom)

[Loyal]

In short, in high school Chemistry it is mostly memorization when it comes to acid strength.   It isn't till at least Organic Chemistry in college that you start to learn how to determine acid strength by structure.  There aren't too many strong acids.   A general rule of thumb is if it isn't HCl, HI, HBr, HNO₃, H₂SO₄, or HClO₄ then most likely it isn't a strong acid.  There are a few exceptions, but not too many that you will see. 

Most strong bases you will encounter have xOH where x is usually an alkali  ion or a alkaline ion.