# 40.0g NaCl that is 90% by Mass, find Mass

1. Jan 12, 2010

### BKHuff

1. You will prepare 40.0g of a NaCl solution that is 0.90% by mass. Calculate the mass of the NaCl that is needed.

2. I don't know the proper equations/steps to find the answer, this is really what I need help with.

3. I have not made an attempt yet as I don't know how to go about making an attempt. Hopefully somebody could point me in the right direction so I can figure this out.

Also I did do a search though I was unable to find anything that seemed to deal with my situation.

-Britt

2. Jan 12, 2010

### Bohrok

Try looking at it this way first: If you needed to prepare a 100. g solution of NaCl that is 10.0% by mass, what mass of NaCl is needed?

3. Jan 12, 2010

### Staff: Mentor

Other hint: you can solve the question using just definition of mass percentage and basic algebra to rearrange the formula.

Last edited by a moderator: Aug 13, 2013
4. Jan 13, 2010

### BKHuff

Thanks for the help it seemed I was over thinking the question a bit. I came up with 0.36g NaCl

5. Jan 13, 2010

### Staff: Mentor

Can't say I am surpsised

Last edited by a moderator: Aug 13, 2013