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Topic: Lab techniques  (Read 25892 times)

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Offline Messi

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Re: Lab techniques
« Reply #45 on: November 10, 2012, 12:53:00 AM »
Again, explained so nicely! Thank you!

Offline Messi

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Re: Lab techniques
« Reply #46 on: November 12, 2012, 08:38:38 PM »
ANOTHER Lab technique question! :)

How do I know how much solvent I should add to my reaction!?

My reaction includes 0.15g of sulfur, 1mL of an amine, 0.3mL of an alkyne and 0.2mL of an acid, 0.4mL of a strong base.

Thanks!

Offline fledarmus

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Re: Lab techniques
« Reply #47 on: November 12, 2012, 08:45:02 PM »
Hopefully, the procedure you got from a publication will give you some indication of a concentration. If not, you sort of have to pick a concentration and hope for the best. After a while you get good at figuring out which reactions are going to go very fast and may need to be run more dilute, and which ones will be slow and will need to be concentrated. And of course, the solubility of your starting materials or products may determine how much solvent you need.

Usually I would start with ~0.1 to ~1 M of my limiting reagent in the solvent. Smaller reactions I tended to run a little more dilute, just because it is hard to measure and manipulate very small quantities of solvent.

Offline Messi

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Re: Lab techniques
« Reply #48 on: November 12, 2012, 09:48:15 PM »
After a while you get good at figuring out which reactions are going to go very fast and may need to be run more dilute, and which ones will be slow and will need to be concentrated.

Why do fast reactions need to be run more dilute?

Offline Borek

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Re: Lab techniques
« Reply #49 on: November 13, 2012, 03:57:00 AM »
When you dilute you slow down the reaction, that makes it easier to control.
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Offline Messi

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Re: Lab techniques
« Reply #50 on: November 14, 2012, 09:21:56 PM »
Thanks Borek

Offline Messi

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Re: Lab techniques
« Reply #51 on: November 14, 2012, 09:22:30 PM »
ANOTHER technique question :)

Is it ok to run two SIMULTANEOUS reactions in the same fumehood!?

Two for the price of one. Save some time :)


Offline Messi

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Re: Lab techniques
« Reply #53 on: November 14, 2012, 09:54:05 PM »
Run as many reactions as you want!

Now that's what I call epic!

Too bad my school is old and everything is done with my two hands :(

Maybe Santa will find me this year though? :)

Offline discodermolide

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Re: Lab techniques
« Reply #54 on: November 14, 2012, 11:11:00 PM »
You mean you want hands for Xmas? You'd better write to Santa now then he must have a forum somewhere on the net.
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Offline curiouscat

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Re: Lab techniques
« Reply #55 on: November 14, 2012, 11:38:25 PM »
You mean you want hands for Xmas? You'd better write to Santa now then he must have a forum somewhere on the net.

You can actually post a card marked "Santa, North Pole" and it gets delivered to him!

Offline discodermolide

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Re: Lab techniques
« Reply #56 on: November 14, 2012, 11:43:02 PM »
I do that every year but it obviously never gets there as I never get what I put on the card :-\
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Offline curiouscat

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Re: Lab techniques
« Reply #57 on: November 15, 2012, 12:11:09 AM »
I do that every year but it obviously never gets there as I never get what I put on the card :-\

Maybe you just weren't good enough in the years past?

Offline discodermolide

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Re: Lab techniques
« Reply #58 on: November 15, 2012, 12:14:03 AM »
That could be ???
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Offline Borek

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Re: Lab techniques
« Reply #59 on: November 15, 2012, 03:07:56 AM »
You can actually post a card marked "Santa, North Pole" and it gets delivered to him!

These cards are actually delivered to Rovaniemi on arctic circle. Been there two years ago.
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