Need help identifying conjugate bases and acids

I understand what they both are, but sometimes get them confused when trying to identify them in an equation.

For example: NH4+ (aq) + H2O (l) <----> NH3 (aq) + H3O+ (aq)

My teacher labeled NH4+ as the conjugate acid, NH3 as the base, H2O as the conjugate base, and H3O+ as the acid.

How do I know to label it like that instead of NH4+ as the acid, NH3 as the conjugate base, H2O as the base, and H3O+ as the conjugate acid????

This is a trick 2 know about acids and bases. Rember an acid is a proton donor and a base is a proton acceptor.
> In this case the :
The NH4+ ( means that it lost one)
And the NH3 (there is no sign which means that it gained) this is why NH3 is a base. (it's a proton acceptor)
> the H2O went to H3O+ ( this means that it lost one because of the sign +)
This is why H3O+ is an acid ( a proton donor)

I hope I helped :)
Gd luck x

I don't see a difference between what you are saying and what your teacher is saying. If you know the difference then that's all you need to worry about.