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A couple of curiositys.

Migrated topic.

Xt

.
Senior Member
OG Pioneer
So i saw a beaker with some IPA the other day. It did not sit flat or level in the beaker. What i mean is the sides of the liquid where it made contact with the beaker were convex. Not just immediately at the edge but quite some way in. Almost like the liquid was bulging out.

What causes this?

Secondly, a friend and i were discussing chemistry, a question came up.
Say your using water to crash something out of an alcohol or solvent, what effect would using De-ionized water have over regular water?

X
 
Well, I can answer your first question, but I'm not too sure on your second one. IPA is a liquid and liquids take the shape of the container you put them in. This means that if you have a container that has a convex bottom, the fluid in that container will reflect that. This is the reason that when you are reading the measaurements off the side of a graduated cylinder or beaker or flask, you are supposed to look at the measuring lines at your eye level to get an accurate volume measurement. If you look at the lines from above, it is possible to misread the amount as the volume is wherever the center of the top layer of liquid is at it's lowest. At least, this is what I remember from a lab long long ago. Hope it helps (and I'm not out in left field talking outta my wormhole).

SB
 
yes, the curvature of the surface of a liquid is called a meniscus. However sb, I don't think the phenomenon has anything to do with the shape of the bottom of the container, respectfully, I think it has to do with attraction to the sides of the container at the surface; for instance, mercury will form a convex meniscus even when placed in a container with a concave bottom, this has to do with the fact that mercury is more attracted to itself than the glass, where as water and most other substance will attract to the container.:d

SCIENCE!

as for your second question, how would a saturated solvent separate in response to water? I do not follow but my knowledge is limit
 
xtechre said:
Say your using water to crash something out of an alcohol or solvent, what effect would using De-ionized water have over regular water?
X

ions in tap water may form complexes with compounds with charged groups, forming extraneous salts.
not particularly desirable, yields are higher (due to increased mass from the salts), but product is very impure. use DI water whenever possible.
 
Meniscus, plural: menisci/meniscuses, from the Greek for "crescent", is a curve in the surface of a molecular substance and is produced in response to the surface of the container or another object. It can be either concave or convex. A convex meniscus occurs when the molecules have a stronger attraction to each other than to the container.[1] This may be seen between mercury and glass in barometers.[1] Conversely, a concave meniscus occurs when the molecules of the liquid attract those of the container. This can be seen between water and an unfilled glass. One can over-fill a glass with water, producing a convex meniscus that raises above the top of the glass, due to surface tension.

wikipedia

there ya go (for the first question anyway.)

JBArk
 
benzyme said:
xtechre said:
Say your using water to crash something out of an alcohol or solvent, what effect would using De-ionized water have over regular water?
X

ions in tap water may form complexes with compounds with charged groups, forming extraneous salts.
not particularly desirable, yields are higher (due to increased mass from the salts), but product is very impure. use DI water whenever possible.

I assumed something like that would occur.
Or perhaps the lack of ions would reduce the amount of crashing out good the desired product.
Well i got my answers.

Thanks folks!
 
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