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# Preparation of a %NACL solution

w/v solution

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### #1 Dima

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Posted 12 August 2013 - 08:19 AM

Sorry for this basic question on a professional forum!!

it has been a while since I worked in the preparation of stock solutions and now am back to learning happily.

I just need to prepare a 1056 ml solution (not water) containing 2.1% NACL. Shall I just add 21 g of NACL and make it up to 1056 and If so I need to first dilute the salt to make it up, would not this change the final concentration?

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Posted 12 August 2013 - 09:22 AM

22.176g NaCl in 1056ml solutions?

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### #3 Dima

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Posted 12 August 2013 - 09:32 AM

So I just add it up? i thought there is an equation to convert ml into g since 2.1% may be expressed as w/w rather than w/v . could be i am complicating the simple issue. Thx for the reply!

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Posted 12 August 2013 - 09:46 AM

In practice, % usually is meaning  "w/v" or "g/ml"

Can refer to this promega's technical manual on the way they suggest to prepare 10% SDS Solution, 100g in final volume of 1000ml solutions:

http://www.promega.c...b Solutions.pdf

Expecting the world to treat you fairly because you are a good person is like expecting the lion not to attack you because you are a vegetarian.

..."best of our knowledge, as far as we know this had never been reported before, though I can't possible read all the published journals on earth, but by perform thorough search in google, the keywords did not match any documents"...

"what doesn't kill you, makes you stronger"---Goddess Casandra reminds me to be strong

"It's all just DNA. Do it."---phage434

### #5 phage434

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Posted 12 August 2013 - 12:18 PM

% usually means grams/100 ml.  It's an ugly standard, but there it is. Perhaps justified by noting that 100 ml weighs 100 g, so you can think of this a bit like a w/w measurement, but this is wrong in more complex situations.

### #6 Dima

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Posted 15 August 2013 - 07:39 AM

Many many thanks for the continuous supportive forum!!