Basically we performed this reaction in lab (specifically we started with 2.7g of acetanilide (step 2) then went to 3b and 4b to end up with p-nitroaniline.

http://en.wikipedia.org/wiki/File:Synthesis_of_nitroaniline.svg

My goal is to write a balanced chemical equation and the percent yield (which once I just need the theoretical yield and I know how to do the rest) Thanks!

OK

I'm a little confused about what you are asking for...

The step from 2 to 3b is an electrophilic substitution. You have

NO_2\ ^+ formed from reacting conc. HNO3 and conc. H2SO4, substituting H^+ in the ring.

Then, you are hydrolysing the peptide bond which forms p-nitroaniline and the carboxylic acid ethanoic acid.

Hence, you start with 1 mol of 2, reacting with 1 mol of nitronium ion and 1 mol of water to form 1 mol of p-nitroaniline, 1 mol of H^+ ions and 1 mol of ethanoic acid.

Surely you remember how to determine a theoretical yield!
Your Wiki reference shows the balanced reaction. Note you get both the a and b products; you don't just "go on to 3b and 4b"
That's why you are asked for the percent yield.
So: how many moles is 2,7g of acetanilide?
How much does that many moles of p-nitroaniline weigh?
I think I would refer to the protecting group as an amide rather than a peptide. (All peptides are amides, but not vice versa.)

Another thought: don't you just love a reaction that uses Nitric Acid as a base!!