Page 1 of 1

### Half Life Equations

Posted: Mon Mar 09, 2020 4:59 pm
Do we need to memorize the half life equations for zeroth and second order rate laws? Will they be given on the equation sheet for the final?

### Re: Half Life Equations

Posted: Mon Mar 09, 2020 5:21 pm
I'm pretty sure they were written on our tests last week so it's likely that they'll be provided. It doesn't hurt to memorize them though.

### Re: Half Life Equations

Posted: Mon Mar 09, 2020 10:01 pm
I think they will be provided!

### Re: Half Life Equations

Posted: Wed Mar 11, 2020 4:47 pm
They should be provided, but it may be easier to memorize which equation goes with which order.

### Re: Half Life Equations

Posted: Wed Mar 11, 2020 4:52 pm
It's an open book final...

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 10:29 am
For Zero Order reaction: t½ = [Ao] / 2k
For First Order reaction: t½ = 0.693 / k
For Second Order Reaction: t½ = 1 / k [Ao]

They are given, but they are not labeled on the constants sheet.

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 12:49 pm
i'm pretty sure they will be given but the final is also open book

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 1:37 pm
As the final is open-book, this shouldn't be a concern anymore, but the homework question (7A.7 I believe) that discusses the units of the rate constant for different rate orders is good to review on this topic.

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 1:42 pm
They are typically provided on the list of given equations!

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 2:26 pm
can someone explain their importance/use?

### Re: Half Life Equations

Posted: Thu Mar 12, 2020 2:31 pm
The 0th, 1st, and 2nd order equations are provided on the equation sheet but the equation sheet doesn't specify which one is which. So if you are doing your test with the equation sheet I recommend labeling each one so you don't mix them up.