[sgreen49]

Ok so I am pretty confused on this one question.  If you could please help me I would greatly appreciate it!

Assuming that you would have no losses, how many grams of salicylic acid would be needed as starting material to produce 45.00 g of aspirin?

[delta609]

First thing I would do is start by balancing the chemical equation of the formation of the aspirin.  Then all I would do is use a conversion factors to find the amount of salicylic acid needed. 

If you don't know how to do conversion factors, then you should learn.  They can be pretty nifty. 

[sgreen49]

The only problem is I can't balance the equation.
C7H6O3+C4H6O5 --> C9H8O4

[delta609]

Acetic acid is also a product

[sgreen49]

It is?  Why?  Sorry, I am just REALLY confused and am trying to get this.

[delta609]

Why would be an explanation that I don't feel qualified to answer, but I can tell you that substances will react to form more stable states with less potential energy.  Maybe someone else on this forum can shed a little more light on this for you.

As for balancing your equation, it should read C7H6O3 (Salicylic acid) + C4H6O3 (Ethanoic anhydride) => C9H8O4 (Aspirin) + C2H4O2 (Acetic acid).  I remember doing this is in a Chem I lab.  All you really have to know to answer your initial question is that everything reacts in a 1:1 mole ratio, then you can just use conversion factors. 

[Borek]

As for balancing your equation, it should read C7H6O3 (Salicylic acid) + C4H6O3 (Ethanoic anhydride) => C9H8O4 (Aspirin) + C2H4O2 (Acetic acid).

That's assuming you use anhydride, I don't think it is the only possible approach.

All you really have to know to answer your initial question is that everything reacts in a 1:1 mole ratio, then you can just use conversion factors.

That's much better. There is one molecules of the aspirin produced for every molecule of salicylic acid. It is quite easy to see when you look at the reaction equation written using structural formulae, not the molecular formulae.

Edit: missing "only" added, sorry about that.