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Topic: Measuring Cyinder v Volumentric Flask  (Read 2964 times)

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Offline defencegrid

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Measuring Cyinder v Volumentric Flask
« on: January 27, 2017, 06:06:02 AM »
I don't get the point of using a measuring cylinder to make a solution as opposed to using a volumetric flask.  I know you don't need to use a volumetric flask unless you need high accuracy, but using a measuring cylinder to make a solution is no faster.  And with a volumetric flask you can just stopper it and invert it to mix the solution while you can't invert a measuring cylinder to mix the final solution.

Offline Irlanur

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Re: Measuring Cyinder v Volumentric Flask
« Reply #1 on: January 27, 2017, 07:10:28 AM »
try measuring 95 ml with a volumetric flask...

Offline defencegrid

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Re: Measuring Cyinder v Volumentric Flask
« Reply #2 on: January 27, 2017, 05:33:26 PM »
try measuring 95 ml with a volumetric flask...

Why would you make a 95ml solution? Just make 100ml.

Offline Arkcon

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Re: Measuring Cyinder v Volumentric Flask
« Reply #3 on: January 27, 2017, 06:51:04 PM »
I routinely make a dozen solutions, of varying volumes, from 30, to 33, to 37, to 53 mL.  As was said, they don't make flasks in 1 mL increments.  My reagents cost hundreds of dollars a gram, and react with moisture and oxygen -- I can't make 100 mL, use 33 mL, and keep them for a month or discard 64 mL.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline defencegrid

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Re: Measuring Cyinder v Volumentric Flask
« Reply #4 on: January 27, 2017, 08:26:38 PM »
I routinely make a dozen solutions, of varying volumes, from 30, to 33, to 37, to 53 mL.  As was said, they don't make flasks in 1 mL increments.  My reagents cost hundreds of dollars a gram, and react with moisture and oxygen -- I can't make 100 mL, use 33 mL, and keep them for a month or discard 64 mL.

If you needed to make a 100ml solution, would you still use a measuring cylinder?

Offline hypervalent_iodine

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Re: Measuring Cyinder v Volumentric Flask
« Reply #5 on: January 27, 2017, 08:35:26 PM »
Even if I need to make a 100 mL solution, if I don't need accuracy then I m not going to bother with a volumetric. It is in fact a bit of added hassle. Most of the things I would be using a measuring cylinder for would be for mixing liquids anyway. In that case, I'd need two volumetric flasks or a volumetric pipette, and I'd need them in increments they probably don't come in. As for why not round up what you make to the nearest volumetric flask volume, the simple answer is because it's wasteful.

Offline Arkcon

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Re: Measuring Cyinder v Volumentric Flask
« Reply #6 on: January 28, 2017, 06:30:23 AM »
If you needed to make a 100ml solution, would you still use a measuring cylinder?

As was said, almost certainly.  The volumetric flask is for greater accuracy.  I disagree with your premise -- I routinely make 1 liter mobile phases, I mix the components in ~800 ml water, and bring the resulting solution to 1.0 L in a graduate quickly.  The volumetric take some time to learn to use, but is only a little bit slower.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline defencegrid

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Re: Measuring Cyinder v Volumentric Flask
« Reply #7 on: January 29, 2017, 08:53:08 PM »
I don't see the difference in terms of speed.

Instead of mixing the components and adding them to the measuring cylinder,  you're mixing the components and adding them to the volumetric flask.

Offline Borek

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Re: Measuring Cyinder v Volumentric Flask
« Reply #8 on: January 30, 2017, 03:20:24 AM »
I don't see the difference in terms of speed.

Instead of mixing the components and adding them to the measuring cylinder,  you're mixing the components and adding them to the volumetric flask.

You know better and you decided to ignore half of what is said. Further discussion is a waste of time.

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