Find Limiting Reactant: Homework Help

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In summary, the conversation discusses finding the limiting reactant in a chemical reaction using information from a lab handout. It is determined that the (CH3CO)2O is the limiting reagent due to its smaller number of moles available to react. The conversation also briefly touches on the compound NH2 and its potential role in the reaction.
  • #1
Saladsamurai
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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?
 
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  • #2
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!
 
  • #3
MustBe said:
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
 
  • #4
What is NH2?
 
  • #5
Borek said:
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.
 
  • #6
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.
 

1. What is a limiting reactant?

A limiting reactant is the reactant that is completely consumed in a chemical reaction, thus limiting the amount of products that can be formed. It determines the maximum amount of product that can be produced.

2. How do I find the limiting reactant?

To find the limiting reactant, you must first determine the moles of each reactant present. Then, use the mole ratio between the reactants and the desired product to calculate the theoretical yield for each reactant. The reactant with the lower theoretical yield is the limiting reactant.

3. Why is it important to identify the limiting reactant?

Identifying the limiting reactant is important because it allows us to determine the maximum amount of product that can be produced in a reaction. It also helps in determining the amount of excess reactants present, which can affect the efficiency and cost of the reaction.

4. What happens if there is no limiting reactant?

If there is no limiting reactant, it means that both reactants are present in excess and there is no limitation on the amount of product that can be formed. In this case, the reactant with the higher amount present will determine the amount of product that is formed.

5. Can the limiting reactant change during a reaction?

Yes, the limiting reactant can change during a reaction if one of the reactants is completely consumed before the other. This can happen if the reactants are not in the correct stoichiometric ratio, or if the reaction conditions change.

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