Half Lives?  [ENDORSED]


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Hellen Truong 2J
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Half Lives?

Postby Hellen Truong 2J » Fri Mar 09, 2018 8:52 am

Is it accurate to use half lives for questions that say something like 1/4 of the reactant is remaining?

Christine Wastila 1H
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Re: Half Lives?

Postby Christine Wastila 1H » Fri Mar 09, 2018 9:00 am

Yes because that would indicate that the species has undergone two half-lives.

skalvakota2H
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Re: Half Lives?

Postby skalvakota2H » Fri Mar 09, 2018 12:14 pm

In general, at any stage of the reaction, we can find how much of a reactant is remaining after n half-lives by (1/2)^n [A]0. Thus, if 1/2 is a factor of the remaining amount, then it is allowed to use the half life method.

CalebBurns3L
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Re: Half Lives?

Postby CalebBurns3L » Fri Mar 09, 2018 12:18 pm

Yes, you would simply calculate the half life and then multiple it by 2 get the time to reach 1/4 of the reactant remaining.

Ilan Shavolian 1K
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Re: Half Lives?

Postby Ilan Shavolian 1K » Sat Mar 10, 2018 10:17 pm

yes because 1/4th product is = the amount left after two half lives

Fatima_Iqbal_2E
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Re: Half Lives?  [ENDORSED]

Postby Fatima_Iqbal_2E » Sat Mar 10, 2018 10:56 pm

Yes, because you would be able to multiply the half-life by the number of times it occurred to find the time it would take to reach the new concentration.

snehabhargava
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Re: Half Lives?

Postby snehabhargava » Mon Mar 12, 2018 6:05 pm

yes, because 1/4 is the half life of the half life.

Timothy Kim 1B
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Re: Half Lives?

Postby Timothy Kim 1B » Mon Mar 12, 2018 10:19 pm

Yes, half-life works for that fraction.


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