January 25, 2021, 03:15:07 AM
Forum Rules: Read This Before Posting

### Topic: overall dilution factor  (Read 568 times)

0 Members and 1 Guest are viewing this topic.

• New Member
• Posts: 7
• Mole Snacks: +0/-0
##### overall dilution factor
« on: January 13, 2021, 01:38:44 AM »
If your unknown solution is first diluted 30 times and then a 17ml aliquot is taken and diluted in a 50.00ml volumetric flask, what is the overall dilution factor?

I thought it was DF = 1/30 * 50/16
(but the answer's wrong. I'm not sure what to do with the 30 times part)

• New Member
• Posts: 7
• Mole Snacks: +0/-0
##### overall dilution factor
« Reply #1 on: January 13, 2021, 03:04:02 AM »
If your unknown solution is first diluted 25 times and then a 14ml aliquot is taken and diluted in a 50.00ml volumetric flask, what is the overall dilution factor?

I thought it was DF = (1/25)(50/14) since DF = V2/V1. I believe the 25 times portion is wrong but I don't know how to fix it.

#### billnotgatez

• Global Moderator
• Sr. Member
• Posts: 4125
• Mole Snacks: +215/-58
• Gender:
##### Re: overall dilution factor
« Reply #2 on: January 13, 2021, 03:17:24 AM »
posts are merged since both are so similar

also if you have not read the forum rules please do so
This is a forum policy.
Click on the link near the top center of the forum page.
Forum Rules: Read This Before Posting.
http://www.chemicalforums.com/index.php?topic=65859.0

see
4.6 Don't post more than once
in forum rules
« Last Edit: January 13, 2021, 03:28:01 AM by billnotgatez »

#### AWK

• Retired Staff
• Sr. Member
• Posts: 7872
• Mole Snacks: +546/-92
• Gender:
##### Re: overall dilution factor
« Reply #3 on: January 13, 2021, 04:52:01 AM »
Knowing only the meaning of the word "dilution" you should arrange these three numbers so that the answer is correct.
AWK

#### Babcock_Hall

• Chemist
• Sr. Member
• Posts: 4480
• Mole Snacks: +273/-19
##### Re: overall dilution factor
« Reply #4 on: January 13, 2021, 08:39:00 AM »
A definition such as DF = V2/V1 is prone to being misapplied when one is working with serial dilutions.  One might try to find the final concentration this solution first, then come back to what is meant by the overall dilution factor.

• New Member
• Posts: 7
• Mole Snacks: +0/-0
##### Re: overall dilution factor
« Reply #5 on: January 14, 2021, 03:14:09 AM »
A definition such as DF = V2/V1 is prone to being misapplied when one is working with serial dilutions.  One might try to find the final concentration this solution first, then come back to what is meant by the overall dilution factor.

How would you find the final concentration? I am not given any other values except the ones in the question... Thanks!

#### AWK

• Retired Staff
• Sr. Member
• Posts: 7872
• Mole Snacks: +546/-92
• Gender:
##### Re: overall dilution factor
« Reply #6 on: January 14, 2021, 03:37:58 AM »
You have a two-step dilution. The first step is given directly and the second step is given by the volume of the solutions.
How do you calculate the total dilution from two consecutive dilutions?
AWK

#### Babcock_Hall

• Chemist
• Sr. Member
• Posts: 4480
• Mole Snacks: +273/-19
##### Re: overall dilution factor
« Reply #7 on: January 14, 2021, 02:09:58 PM »
If you are having trouble getting started, I suggest that the undiluted solution has a concentration C1, the once-diluted solution has a concentration C2, and the twice-diluted solution has a concentration C3.

• New Member
• Posts: 7
• Mole Snacks: +0/-0
##### Re: overall dilution factor
« Reply #8 on: January 15, 2021, 12:38:13 AM »
For overall dilution factor, I know you're supposed to get the individual dilution factor then multiply them so would it be DF = 30 * 50/16?

Thanks!

#### AWK

• Retired Staff
• Sr. Member
• Posts: 7872
• Mole Snacks: +546/-92
• Gender:
##### Re: overall dilution factor
« Reply #9 on: January 15, 2021, 12:47:27 AM »
Quote
17ml aliquot is taken
One number in your post was different.
AWK