Why does the Limiting Reactant only affect the other reactant and not affect the product?  [ENDORSED]

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Cindy Adiwidjaja 1B
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Joined: Sat Jul 20, 2019 12:15 am

Why does the Limiting Reactant only affect the other reactant and not affect the product?

Postby Cindy Adiwidjaja 1B » Wed Oct 02, 2019 11:37 pm

In the example problem given in class, is was discovered that the CaC2 limited the H2O. However, since the CaC2 is the limiting reactant and not allowing the water to reach its full potential, how come the products produced are not limited as well? If we have less of the CaC2, shouldn't both the other reactant AND the products be hindered by the lack of CaC2?

Myka G 1l
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Joined: Fri Aug 30, 2019 12:17 am

Re: Why does the Limiting Reactant only affect the other reactant and not affect the product?  [ENDORSED]

Postby Myka G 1l » Wed Oct 02, 2019 11:41 pm

The CaC2 is limiting the amount of product formed. 100g of CaC2 produces 40.6 g of the product C2H2, while 100g of H20 produces 72.3g of the product C2H2. CaC2 limits the entire reaction, causing the theoretical yield to be 40.6g of C2H2.

JustinHorriat_4f
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Re: Why does the Limiting Reactant only affect the other reactant and not affect the product?

Postby JustinHorriat_4f » Wed Oct 02, 2019 11:42 pm

A limiting reactant is a substance that is limited because it is totally consumed when the reaction happens, and when it is consumed the reaction can't occur without it. Therefore, i wouldn't think of it as not allowing water to reach its full potential rather it should be that we have excess amount of water, and we won't use all of it when the reaction is complete. Furthermore, the products created are also in a way limited by the limited reactant because if there is more the limiting reactant then more of the products can be created. Hope this helps.

RobertXu_2J
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Re: Why does the Limiting Reactant only affect the other reactant and not affect the product?

Postby RobertXu_2J » Wed Oct 02, 2019 11:47 pm

The products are being limited. Because there is a limited supply of CaC2, the reaction will eventually reach a point where there is no more CaC2, and therefore no more product being produced. It's like making a hamburger: no matter how much cheese (H2O) you have, if you run out of buns (CaC2), you can't produce anymore hamburgers.

Emily Chirila 2E
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Joined: Sat Jul 20, 2019 12:16 am

Re: Why does the Limiting Reactant only affect the other reactant and not affect the product?

Postby Emily Chirila 2E » Thu Oct 03, 2019 1:17 am

I found the analogy of making brownies very helpful in understanding this concept. If you need 2 eggs and 2 cups of flour to make a batch of brownies, and you have 1 egg and 2 cups of flour, you can only make half a batch of brownies because each ingredient must be used in the same ratio it is called for in the recipe (chemical equation). Thus, the extra cup of flour (excess reactant) is left unused since there is no egg left to react with it. Same goes for molecules in chemical reactions! :) Technically the product is affected as well because you can only produce as much as the limiting reactant is able to produce (calculated through dimensional analysis).


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