June 2008 - Chemistry

<p>Yeah, I think it was hydrogen and helium, not argon and helium.</p>

<p>My bad, sorry. It was 22.4 L of He at STP. I just mixed them up.</p>

<p>Did I just misread the T/F question about NaCl in water, or was the first statement that adding NaCl increases the freezing point?</p>

<p>yea, that is what it said so it was F T</p>

<p>Yeah, I'm really sure that it said higher, not lower freezing pt</p>

<p>For a reasoning one. Salt water increases freezin point BECAUSE all aqueous solutions have the same vapor pressure as watter</p>

<p>FF becuz salt water would have a lower freezing point and aqueous solutions would have a lower vapor pressure.</p>

<p>btw everyone, the chat room is talking about the tricky gas problem where temp and pressure changed and we had to find new volume.
it was 200L<em>(newpressure/oldpressure)</em>(old temp in K/new temp in K)
temp is inverse. pressure is regular proportion.</p>

<p>how about that question about diatomic elements? X2
nonpolar and linear o.o</p>

<p>hockydood, all of them are nonpolar and linear so it was TTCE</p>

<p>(@ rjacob) yes. adding a solute decreases intermolecular forces, which in turn changes the vapor pressure.</p>

<p>@ rjacob Yup. For a moment I thought the first part of what you wrote was your answer, I was like noooo...that's not right.</p>

<p>No, I don't think the fact diatomic mole are linear explain that they are non polar. There are ionic bonds that are linear too</p>

<p>LiF
NaCl are all linear'</p>

<p>For that question it'd be only TT. Not CE</p>

<p>for that new pressure problem u had to use P1V1/T1=P2V2/T2</p>

<p>so V2=(P1)(V1)(T2)/(P2)(T1)</p>

<p>that is what i put for the diatomic linear one</p>

<p>I assumed diatomic meeant 2 of the same atom</p>

<p>well, there are only 7 or so diatomics, and they're all linear, so yes</p>

<p>Diatomic was TT, no CE. Diatomic molecules are nonpolar because the atoms have identical electronegativity. Although linear arrangement plays into it, it wasn't why.</p>

<p>Actually, just b'c it's diatomics have a linear orientation doesn't mean it's non-polar. I said it was TT. A linear mc can be HF, and that's a VERY polar mc.</p>

<p>The reason the diatomic molecules are nonpolar is because they have the same electronegativity (because they are the same molecule) Polarmolecules can be linear too.</p>

<p>o wait, i think that it should be F T because the def of a diatomic molecule isnt the same molecule, it is a molecule composed of 2 atoms.</p>