Stociometric calculations

[gwiyomi17]

Are stoichiometric calculations an effective way to predict limiting reagent and excess reagent?

 

This is one of the questions asked from the lab report that I am doing. My problem is how to explain this, I know that it is an effective way because I got the limiting reagent in the experiment same as my calculations. But I think that's not a proper way on how to explain this. CAn someone help me please?

[krash661]

oh my,

i have not touched Stoichiometry in a while.

 

interesting.

most stoichiometric problems can be solved with these four steps,

 

balance the equation.

convert units of a given substance to moles.

using the mole ratio, calculate the moles of substance yielded by the reaction.

convert moles of wanted substance to desired units.

 

i'm not sure if that will help you.

[gwiyomi17]

oh my,

i have not touched Stoichiometry in a while.

 

interesting.

most stoichiometric problems can be solved with these four steps,

 

balance the equation.

convert units of a given substance to moles.

using the mole ratio, calculate the moles of substance yielded by the reaction.

convert moles of wanted substance to desired units.

 

i'm not sure if that will help you.

Thanks for your respond ,

but I don't think it is not the answer to my question.

It's like how is stoichiometric calculation an effective way of predicting the limiting and excess reagent ??

[pwagen]

Without being in any way, shape or form proficient in chemistry, I would say yes, simply because that seems to be exactly what this paragraph suggests.

 

 

A stoichiometric amount or stoichiometric ratio of a reagent is the optimum amount or ratio where, assuming that the reaction proceeds to completion:

1. All of the reagent is consumed,
2. There is no deficiency of the reagent,
3. There is no excess of the reagent.

A non-stoichiometric mixture, where reactions have gone to completion, will have only the limiting reagent consumed completely.

Source

[krash661]

ok, there's a lot to explain here,

i'm not much of a typer so i'll refer you to this link,

i've skimmed through it.it appears everything you need is there.

 

http://www.science.uwaterloo.ca/~cchieh/cact/c120/limitn.html

 

edit-

ahh yes, try that link pwagen provided.

Edited May 2, 2013 by krash661

[gwiyomi17]

Without being in any way, shape or form proficient in chemistry, I would say yes, simply because that seems to be exactly what this paragraph suggests.

 

 

Source

 

ok, there's a lot to explain here,

i'm not much of a typer so i'll refer you to this link,

i've skimmed through it.it appears everything you need is there.

 

http://www.science.uwaterloo.ca/~cchieh/cact/c120/limitn.html

 

edit-

ahh yes, try that link pwagen provided.

 

That makes sense,

maybe I could just add some information about the result of the experiment.

Thanks guys!

[pwagen]

maybe I could just add some information about the result of the experiment.

Feel free to. Always interesting to see what people come up with.

[krash661]

i agree.

[gwiyomi17]

1.)

1. Summarize
   your findings. Are stoichiometric calculations an effective way to predict
   limiting reagent and excess reagent? Explain.

According
to the findings of this experiment, the reaction between the 2 g of cupric chloride
and the 0.5 g of aluminum would yield aluminum chloride and copper precipitate.
The experiment shows that the aluminum is the excess reagent because of the
unreacted pieces of aluminum still floating on the solution while the cupric
chloride is the limiting reagent. The theoretical findings proved that the
aluminum is the excess reagent and the limiting reagent is the cupric chloride because
of the calculated number of moles of the product. Hence, a stoichiometric
calculation is an effective way to predict limiting reagent and excess reagent
without conducting actual experiments.

2.)

1. Suggest
   reasons why the percentage yield of the reaction was not 100%?

If a yield is 100%, it means that no product has been
lost. But if the yield is 0% it means that no product has
been made. The reasons why the percentage yield of a product might be less than
100%, includes when:

• There were some impurities in the materials
  used.

• The chemical reaction did not go to a completion.

• Some of the reactants were used and some was
  left or did not react during the chemical reaction. The reactants may not
  always exist in the proportions written in the balanced
  equation.

Hi guys! I'm back. I used your suggestions in answering the second question. Do you mind checkin my answers? thanks.

Edited May 2, 2013 by gwiyomi17

[krash661]

it appears to be fine IMO.

 

great job.

[gwiyomi17]

thanks!

[krash661]

no problem at all.