Homework help (science)

[scaredstiff695]

i like this thread allthough dont really no the questions lol made me smile and forget about anxiety.

hope he gets a good grade now hes got his mummy and mummys friends helping lol xx

used to be caling cheating when i was at school hahah (only kidding)

[SueBee]

The answer is most certianly not density - it has to deal with the size of the molecules and intermolecular forces shared between the molecules. Even though isopropyl alcohol and water arent' the same size (isopropyl is a little bit larger) they do share a critical intermolecular force - hydrogen bonding. This makes it so that when the two molecules come together, they are attracted to one another (as opposed to having no affinity for one another) and thus "pack more closely" to reduce the volume. Unlike you've often learned, volumes ARE NOT additive, to correct a problem like this, scientists usually refer to the partial molar volume of a substance which takes into account interaction with another substance. The same effect can be seen with many other pairs of liquid like water and ethanol or benzene and toluene.

[/B] Eh lol

[lizzie29]

What's the percentage Di? Better be more than 50!

[Nigel]

I will slip you a fiver when the others ain't looking but this is between you amd me only!!!

OK, deal
And for another fiver I’ll pretend I didn’t see that earlier comment

Thanks Lizzie
I found that interesting, and it wasn’t even my homework!

[lizzie29]

Like I said, I didn't come up with that answer sadly! But I thought it was quite interesting too - good bit of pub quiz knowledge!

Okay, if Nigel is now on a tenner, I want that percentage to be 100% Di - you tell Lisa that!

[Nigel]

Thanks Sue.

That sounds cleverer, but I prefer Lizzie’s answer because I can understand it

[lizzie29]

Sue - does yours mean the same as mine?! If you wrote that yourself - blimey, I take my hat off to you!

[SueBee]

LMAO noooooo I didn't write it myself !! Good old google search!

I think it basically means that the molecules of one fit into the spaces of the other, therefore altering the density.

[lizzie29]

Phew! That's what the gist of mine said too.

[SueBee]

LOL lizzie, just read yours - wish my son were here, He's at Uni doing just this subject but I can never guarantee that I'd understand the answer to the question lol