Alysion.org - Medication Math for Nursing Students http://www.alysion.org/dimensional/analysis.htm
Calculators & Converters http://www.endmemo.com/bio/dilution.php
Calculating Concentrations http://chemistry.about.com/od/lecturenotesl3/a/concentration.htm
Formula: C V C V 1 1 2 2
https://docs.google.com/viewer?url=www.delta.jkirkbrown.com%2Fpdf%2Fbiotech%2FLabMath.pdf&docid=89cd6e71da8b4bb628d639988c21494d&a=bi&pagenumber=5&w=784
Definitions:
Dilution - when one substance is added to water to make a more dilute solution. Sometimes they are not in water, but most solutions solutions used in biotech are aqueous used in biotech are aqueous.
Video on Dilution https://www.youtube.com/watch?v=x8wqQL25IRw
Stock = Original substance
Diluent = Solution and the diluting substance
How much 30% stock sodium hydroxide solution should be added to 500 mL of water to make a 5% sodium hydroxide solution
You currently have 500 ml @ 0% sodium hydroxide (it's water!)
You need to add X ml @ 30% sodium hydroxide
You'll then have (500 + X) ml @ 5% sodium hydroxide.
Using decimals for the percents, we multiply the quantity times the concentration %:
500(0) + X(.30) = (500+X)(.05)
0 + .30X = 25 + .05X
.25X = 25
X = 100 ml
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You can also think of this in table form.
0 + .3x = .05(500 + x)
30x = 5(500 + x) = 2500 + 5x
25x = 2500
x = 100
100mL should be added...