Limiting Reactant- Excess

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Naana Boateng 1I
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Joined: Fri Sep 29, 2017 7:07 am

Limiting Reactant- Excess

Postby Naana Boateng 1I » Tue Oct 03, 2017 2:34 pm

When a question asks for a limiting reactant or reagent, does finding the excess mean the other substance that has more product or is there another formula?

Hector Acosta Discussion 1H
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

Re: Limiting Reactant- Excess

Postby Hector Acosta Discussion 1H » Tue Oct 03, 2017 3:33 pm

Which ever reactant is in excess it means that reactant has more product. This would mean that the other reactant is your limiting reactant.

Jordan Foster
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Re: Limiting Reactant- Excess

Postby Jordan Foster » Tue Oct 03, 2017 4:36 pm

The limiting reactant is the reactant that will run out first. This means there will be excess of the other reactant, making it the non limiting reactant. Most calculations will be based off of the limiting reactant because the excess of the non limiting reactant will not be used.

Austin Ho 1E
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Re: Limiting Reactant- Excess

Postby Austin Ho 1E » Tue Oct 03, 2017 8:44 pm

When finding the excess, you must find which reactant is limiting first. Once you've done this, you can then determine which reactants are in excess; i.e. there is some left over that isn't used in the reaction. An easy way to find how much excess is left over is to convert all of your reactants into moles of one reactant, for instance, if you had the reaction 2H2 + O2 -> 2H20, then convert your reactants into moles of H2 or O2 first. Whichever has more moles has the limiting reactant's # of moles subtracted from it, then you'll convert back and find how much you have excess.

McKenna disc 1C
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Re: Limiting Reactant- Excess

Postby McKenna disc 1C » Thu Oct 05, 2017 12:55 pm

The reactant that is in excess will not be consumed entirely in the reaction, whereas in theory the limiting reactant will be consumed entirely and there will be nothing left over. The amount of product formed is based on how many moles you have of the limiting reactant-- however many moles you have of the limiting reactant determines how many moles of product can be formed (along with the molar ratios between reactant and product). Hope this helps! :)


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