# Find Limiting Reactant

## Homework Statement

I have this information from a lab handout

I have:

.40g of NH2 = .25 mol NH2

.58g of (CH3CO)2O = .0092 mol (CH3CO)2O

and the reaction

NH2 + (CH3CO)2O---> HNCOCH3 + CH3COOH

I need to find the limiting reactant

I know that since the only product with N on the right hand side is HNCOCH3 so ALL of its N must have come from the NH2

I am just not sure how to "test" the reactant (CH3CO)2O ? Both products contain all of those elements?

Any thoughts?

Because the entire equation reacts in a 1 to 1 ratio (all stoichiometric proportions are equal) your limiting reagent is the one with the smallest number of moles.
only 0.0092mol of (CH3CO)2O is available to react, and as the number of moles of NH2 that will react with it is in equal proportion (the 1:1 ratio), only 0.0092 of the 0.25 mol NH2 will ever react. Thus, the (CH3CO)2O is the limiting reagant

I may have oversimplified the question, but I hope this helps!

Because the entire equation reacts in a 1 to 1 ratio (all stoichiometric proportions are equal) your limiting reagent is the one with the smallest number of moles.
only 0.0092mol of (CH3CO)2O is available to react, and as the number of moles of NH2 that will react with it is in equal proportion (the 1:1 ratio), only 0.0092 of the 0.25 mol NH2 will ever react. Thus, the (CH3CO)2O is the limiting reagant

I may have oversimplified the question, but I hope this helps!

No, I think it it a matter of me over complicating it! Thanks!

Casey

Borek
Mentor
What is NH2?

What is NH2?

I'm not sure. But I think its an amino group and that because its a cation is available to attach as a amine to carbohydrates and such.

Borek
Mentor
Trick is, such a thing doesn't exist as a separate entity.

My bet is that it was some kind of error, in copying or something.