help with the basics

[B19]

Hey,

 

I am very confused with calculations and I guess I am mixing molecular mass with molar concentration.

 

I just want straight answer for two questions about how to make calculations:

 

1. I have a liquid with molecular weight = 40 and I want to prepare 15ml of 100mM stock. It is not a powder like for example NaCl.

 

2. I have 50ug of lyophylized chemical and molecular weight = 500 and I want to use it all (50ug) to prepare 500mM of stock.

 

Thanks a lot.

 

B19

Edited January 18, 2017 by B19

[Function]

You want straight answers for both questions? That's not how things work here, parvovirus. Show us what you think might be a way to solve the problem and what you've got so far.

 

Should be in the Homework Help section btw ...

Edited January 18, 2017 by Function

[B19]

But then this will be discussion and I don't want any discussion, but answer.

[Phi for All]

But then this will be discussion and I don't want any discussion, but answer.

 

!

Moderator Note

You can get help here, if you can tell us what you have so far, and what part is hanging you up. That's the discussion.

 

You can't get answers here. If we did that, teachers would hate us.

[Function]

Would you go to an oncologist to get a brain cancer removed with surgery?

 

You wouldn't.

 

So don't rely on a forum just to get answers.

 

Forums are not the place to be if you want other people to solve your questions for you.

 

EDIT: oops, sorry Phi. Bit at the same time.

Edited January 18, 2017 by Function

[hypervalent_iodine]

Hey,

 

I am very confused with calculations and I guess I am mixing molecular mass with molar concentration.

 

I just want straight answer for two questions about how to make calculations:

 

1. I have a liquid with molecular weight = 40 and I want to prepare 15ml of 100mM stock. It is not a powder like for example NaCl.

 

2. I have 50ug of lyophylized chemical and molecular weight = 500 and I want to use it all (50ug) to prepare 500mM of stock.

 

Thanks a lot.

 

B19

There are two calculations you need. What calculations do you know of for calculating concentration? Or, what units is concentration usually expressed in (hint: what does mM mean?)