Question

What is the process for calculating a serial dilution that is a 4-step 5 fold process to achieve a specific desired concentration?

Answer 1

In general, a serial dilution is where you dilute successive subsamples of previous dilutions until you reach whatever concentration you're working toward.

For example, if you started off with 10 mLs of 10x running buffer, pulled one mL out and added 9mLs of water to it, you would now have 10mLs of 1x running buffer.

If from that 1x running buffer you pulled one mL, added to it another 9 mLs of water, you would now have 10 mLs of 0.1x running buffer....

This step can be repeated how ever many times you like, adding how ever much water you like relative to your sample to achieve whatever concentration you want.

Hope that's helpful.

Answer 2

For example the concentration of a substance is 3.5 M. If this were diluted in water using a 5 step, 10 fold dilution process, what would the final concentration be?

Im not sure how to tackle this question..

Answer 3

A 10 fold dilution means make a 1 in 10 dilution. That means, 1 part substance to 9 parts water because 1 + 9 = 10. Hence "one in ten."

The initial concentration of a solution is 3.5 M. To do a ten fold dilution, you take 1 mL of whatever you're diluting and mix it with 9 mLs of water. Its concentration is now 0.35 M. That is one step.

The prob asks you for a 5 step process. So to do the second step, you would take 1 mL of the 0.35 M solution you made in the first step, add 9 mLs of water to it and so on...