## 7B.1

Savannah Mance 4G
Posts: 107
Joined: Fri Aug 30, 2019 12:17 am

### 7B.1

For this problem, I'm confused on how to solve the rate equation with the given info. I know I'm supposed to use the equation with K=1/t*ln(A initial)/(A) but I don't get how the initial mass given is put into the equation to solve.

KSong_1J
Posts: 101
Joined: Thu Jul 11, 2019 12:17 am

### Re: 7B.1

You plug the initial mass into [A]initial! I suggest rearranging the equation to [A] = [A]initial*e^-kt to make it easier to solve (since you’re solving for [A]) and don’t forget to convert 5.0 hours into minutes (since the units for k is given as min^-1)! Hope this helps :)

Savannah Mance 4G
Posts: 107
Joined: Fri Aug 30, 2019 12:17 am

### Re: 7B.1

Why can you plug in the grams of the drug if you don't know what volume it is in? Since it's asking for concentration, how come you can plug in the 0.02 grams?

Nick Fiorentino 1E
Posts: 102
Joined: Wed Sep 18, 2019 12:16 am

### Re: 7B.1

I think if you're only given one thing (like mass) then you have to plug it in and it will work as long as you are using like values