Top Posters
Since Sunday
5
o
5
4
m
4
b
4
x
4
a
4
l
4
t
4
S
4
m
3
s
3
New Topic  
leelo leelo
wrote...
Posts: 15
Rep: 0 0
10 years ago
I have 2',7'-dichlorofluoroscein with a MW of 401.20. I need to make a 150 uM stock solution with a final volume of 50 ml. How many grams of the compound should I weigh out?

I have to do a few things like this in lab and I am getting confused when the molarity is in uM and nM. Can you explain exactly how you got your answer? I have one but I'm not sure if I did it correctly.
Read 398 times
2 Replies
Replies
Answer accepted by topic starter
ff.marquisff.marquis
wrote...
Posts: 10
Rep: 0 0
10 years ago
Sign in or Sign up in seconds to unlock everything for free
1

Related Topics

fey
wrote...
10 years ago
The key is to use the units of each measurement to help you with your solution and to keep the units consistent throughout your stoichiometric equation.  For example, instead of writing your equation out with 50 mL to start, write its as 0.050 L; 150 uM can instead be 0.000150 mol/L.  You then just need to put everything together so that all the units cancel out except for grams.  Here's how I would write it:

(0.050 L) * [(0.000150 mol) / (1 L)] * [(401.20 g) / (1 mol)] = 0.0030 g or 3.0 mg
New Topic      
Explore
Post your homework questions and get free online help from our incredible volunteers
  866 People Browsing
 106 Signed Up Today
Related Images
  
 83
  
 168
  
 122
Your Opinion
What percentage of nature vs. nurture dictates human intelligence?
Votes: 387

Previous poll results: How often do you eat-out per week?