Half life


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Abigail Menchaca_1H
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Half life

Postby Abigail Menchaca_1H » Sun Mar 15, 2020 11:52 pm

Where do you start when you determine the half life for a zero order reaction?

Adam Kramer 1A
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Re: Half life

Postby Adam Kramer 1A » Mon Mar 16, 2020 12:14 am

to find the half life of the zero order reaction, you need to use the equation [A.5]=-kt+[A0], where A.5 is half the concentration of A0
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Serena Song 1A
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Re: Half life

Postby Serena Song 1A » Tue Mar 02, 2021 9:21 pm

You could also use t1/2 = [A]0/2k!

clairehathaway 2J
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Re: Half life

Postby clairehathaway 2J » Wed Mar 03, 2021 1:31 pm

Today in lecture (3/3) Dr. Lavelle went through the derivation of finding the equation for the half-life of a zero-order reaction.
He started with the equation , then when looking for we know that . Then we can find that
which simplifies to and ultimately gives us the zero-order half life equation which is:

DMaya_2G
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Re: Half life

Postby DMaya_2G » Wed Mar 03, 2021 4:45 pm

You just simply use the equation t1/2 = [A]0/2k

apurva-3E
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Re: Half life

Postby apurva-3E » Wed Mar 03, 2021 6:52 pm

We can use the reaction: t(1/2) = [A]0/2k

Xinying Wang_3C
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Re: Half life

Postby Xinying Wang_3C » Thu Mar 04, 2021 12:28 am

you could plug numbers into the equation, t(1/2) = [A]0/2k

Samantha Lee 1A
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Re: Half life

Postby Samantha Lee 1A » Thu Mar 04, 2021 11:22 am

The half life of a zero order reaction is

The derivation of this equation was in 3/3 lecture. The integrated rate law for the zero order is . At , [A] = 1/2*([A]_0). When we substitute 1/2[A]_0 into the equation for [A], the equation can be rearranged. The initial concentrations of A can be combined and then we solve for . When we solve for , we get the half life equation for the zero order.

We can either derive the equation every time you want to use the half life equation for each order, using its specific integrated rate law, or you can use the answer of the derivation. The half life equation will be the same for every problem that is of that order.

Stephen Min 1I
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Re: Half life

Postby Stephen Min 1I » Thu Mar 04, 2021 2:22 pm

A 0 order reaction has a half life of t = [A]/2k, which depends on [A] initial.

rhettfarmer-3H
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Re: Half life

Postby rhettfarmer-3H » Sun Mar 07, 2021 4:28 pm

To begin, Half life is when the reaction reaches half the initial amount. Hence, 0.5A=-kt+A. Then becomes -.5A=-kt which more so .5A=kt. So then we get A*1/(2*k)=t. That the half life of zero reaction.

Brian_Wu_3B
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Re: Half life

Postby Brian_Wu_3B » Wed Mar 10, 2021 4:05 pm

Use the half life equation for zero order reactions: t = [A0]/2k

abby hyman
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Re: Half life

Postby abby hyman » Wed Mar 10, 2021 4:35 pm

You must use the specific half life equation for a zero order reaction which is t1/2 = [A]0/2k

aashmi_agrawal_3d
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Re: Half life

Postby aashmi_agrawal_3d » Wed Mar 10, 2021 10:48 pm

You can use the equation t 1/2 = [A] 0/2k

Gian Boco 2G
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Re: Half life

Postby Gian Boco 2G » Fri Mar 12, 2021 11:54 pm

Use t(1/2) = [A]0/2k

Ismar Zamora
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Joined: Mon Jan 04, 2021 11:26 am

Re: Half life

Postby Ismar Zamora » Sat Mar 13, 2021 12:00 am

t(1/2) = [A]0/2k

David Liu 1E
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Joined: Wed Sep 30, 2020 10:07 pm

Re: Half life

Postby David Liu 1E » Sat Mar 13, 2021 3:02 am

we use the equation specifically for half life for zero order reactions! which is the equation everyone else has stated

Joshua Swift
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Joined: Wed Sep 30, 2020 9:50 pm

Re: Half life

Postby Joshua Swift » Sat Mar 13, 2021 12:49 pm

to find the the half life of a zero order reaction:
t1/2 = [A]0/2k

Jerry_T
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Re: Half life

Postby Jerry_T » Sun Mar 14, 2021 1:03 am

Lecture 23
Dervied equation for half-time of a zero order reaction:
t1/2 = [A]0/2k

Edgar Velazquez 2K
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Joined: Wed Nov 20, 2019 12:20 am

Re: Half life

Postby Edgar Velazquez 2K » Sun Mar 14, 2021 11:09 pm

I believe you can use the half-life equation where you divide [A]/2k. The first step is to find the original concentration of the given molecule.

Neha Mukund
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Joined: Fri Sep 24, 2021 5:23 am

Re: Half life

Postby Neha Mukund » Thu Mar 03, 2022 7:23 pm

In order to determine the half-life of a reaction, you can begin by using this equation:
t1/2 = [A]0/2k


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