Dilution Chemistry Problems i dont get it >.<

[king atlantis]

ok, our teacher showed us a ton of stuff today, includeing molarity and dilution. i understand molarity but not dilution...any help please?

Homework Statement

the problems are all like this:
*0.005 L of 1.0 M Hcl is diluted w/ water to 0.125 L
*100.0 ML of 2.0 M HCL is diluted with water to 200 mL.
etc...

The Attempt at a Solution

now, the formula given is M1V1=M2V2

so i would:
0.005L*0.125L=10L*20L
?
for some reason that looks wrong, but like i said, i just don't get it...the teach was a sub, and made it all confusing-like <.<

any help would be appreciated...

 

[rocomath]

well you interpreted all the variables incorrectly

$$M_{1}=\mbox{Molairty}_{\mbox{initial}}$$

$$M_{2}=\mbox{Molarity}_{\mbox{final after dilution}}$$

$$V_{1}=\mbox{Volume}_{\mbox{initial}}$$

$$V_{2}=\mbox{Volume}_{\mbox{final after dilution}}$$

so to answer your first question

$$M_{1}=\mbox{1.0 M HCL}$$
$$V_{1}=0.005L$$

$$V_{2}=0.125L$$

and so, all you need to do is solve for final Volume

$$M_{1} \times V_{1} = M_{2} \times V_{2}$$

*also, always pay attention to your final units

 

[MichaelXY]

It looks to me like your trying to use Boyles Law P1V1=P2V2, I don't think that applies to your problem. Other thing I noticed is the you converted 100ML to 10L, it should be .1L

Also it seems as though part of the question is missing.

 

[rocomath]

It looks to me like your trying to use Boyles Law P1V1=P2V2, I don't think that applies to your problem. Other thing I noticed is the you converted 100ML to 10L, it should be .1L

Also it seems as though part of the question is missing.

Boyle's Law has nothing to do with this problem. He is simply looking for the final Molarity after dilution.

 

[MichaelXY]

Ok, My bad.

 

[rocomath]

Ok, My bad.

Is ok, I'm in Organic 1 and I'm currently reading General Chemistry by Linus Pauling :-] There is still a lot to learn.