Knowing if it's Limiting Reactions

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Faisal Alshamaa - 1L
Posts: 31
Joined: Fri Apr 06, 2018 11:01 am

Knowing if it's Limiting Reactions

Postby Faisal Alshamaa - 1L » Thu Apr 12, 2018 2:13 am

Hello,
On the test, or in general, will the questions asked indicate that the problem is a limiting reactions problem by either mentioning yields or stating to find the limiting reactant or the reactant in excess? In other words, will there be limiting reaction questions that will be disguised as simple molar ratio problems?
Thanks :)

nelquosey
Posts: 31
Joined: Fri Apr 06, 2018 11:02 am

Re: Knowing if it's Limiting Reactions

Postby nelquosey » Thu Apr 12, 2018 9:50 am

I would just be prepared in general with a founded understanding. Also I suggest that you do all the limiting reactant questions that were "assigned" for homework :)

Isabel Jabara 1C
Posts: 34
Joined: Fri Apr 06, 2018 11:03 am

Re: Knowing if it's Limiting Reactions

Postby Isabel Jabara 1C » Thu Apr 12, 2018 12:31 pm

Usually in the textbook the question does not explicitly state that it should be a limiting reactant calculation. You are expected to know how to interpret the information given to you to find out that it is a limiting reactant calculation. I suggest doing the textbook problems without looking at what section it is in so you can learn how to identify a limiting reactant problem from other types of problems.

Jessica Lancisi - 1I
Posts: 29
Joined: Fri Apr 06, 2018 11:03 am

Re: Knowing if it's Limiting Reactions

Postby Jessica Lancisi - 1I » Thu Apr 12, 2018 10:23 pm

Although I know this wont apply to all problems, but often times the questions that are just stoich will give you only one quantity/mass to use in your calculation, and problems that involve limiting reactants will give you 2 or more masses. If you only have one quantity to work with, it cannot be limiting because you dont have another amount to compare it to. I hope that makes sense!

Vienna Cimetta 1L
Posts: 31
Joined: Thu Feb 01, 2018 3:01 am

Re: Knowing if it's Limiting Reactions

Postby Vienna Cimetta 1L » Fri Apr 13, 2018 12:25 am

Sometimes the question will just ask what the mass of a particular product will be in a specific reaction. In this case, you have to find what the limiting reagent is because this will dictate what the mass of the product will be. Therefore, it won't always directly ask you to find the limiting reactant, but you have to know what the concept is in order to reach the right answer.

SamanthaGrohe1B
Posts: 31
Joined: Fri Apr 06, 2018 11:03 am

Re: Knowing if it's Limiting Reactions

Postby SamanthaGrohe1B » Sun Apr 15, 2018 8:56 pm

keep in mind the purpose or the key concept that the question is asking you to utilize. if it is a simple determination of the mass of the products produced by the reaction, stoichiometry can be utilized and the limiting reactant has to be determine. however, if the question is not focusing on that mass of product produced or is focusing on different chemistry topic like acid/ base reactions, the limiting reactant may not be needed to be determined or may be already stated within the problem as that is not a key focus of what the problem is asking you to recall from what you learned.

204917020
Posts: 31
Joined: Fri Apr 06, 2018 11:05 am

Re: Knowing if it's Limiting Reactions

Postby 204917020 » Sun May 20, 2018 1:57 am

Anytime you are given certain amounts of reactants and are asked to find the product, this will be a limiting reactant problem. While it may not say so specifically in the problem, you can know it'a a limiting reactant problem because you can only make as much product as your reactants allow.

For example, if the asked you how many cars can be made if you have 12 wheels and 2 bodies of a car, you can only make 2 cars. So the wheels would be in excess while the body of the car would be your limiting reactant.


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