June 2010: Chemistry

<p>Ahh dwarf, that’s Tin. You probably got it then, because I put Zinc (still a transition metal), but now that I think about it, Tin has Tn2+ and Tn4+.</p>

<p>Can anyone confirm the isomer pictures? Was it:</p>

<p>I. ClH C=C ClH (Cl’s up top on opposite sides, H’s on bottom opposite sides)
II. ClCl C=C HH (Cl’s on left side only now, H’s on right side only)</p>

<p>^ yes it was.</p>

<p>Can someone clarify the 14.7 question? Thanks. Got everything else correct so far I think.</p>

<p>OK then, the isomer answer is none of them are isomers. I and II aren’t isomers.</p>

<p>I put I and II for the isomer pictures, just because they look same, just rearranged</p>

<p>@dwarfwarri: 3d10 4s2 (zinc) is not considered a transition metal because the d orbitals are full. Whereas 3d2 4s2 is - the 4s orbitals always fill up before the 3d orbitals since their energy level is lower. Hope this helps!</p>

<p>

Yes they are, they have the same formula.
[Structural</a> isomer - Wikipedia, the free encyclopedia](<a href=“http://en.wikipedia.org/wiki/Structural_isomerism]Structural”>Structural isomer - Wikipedia)</p>

<p>I think I missed two, anyone want to guess the curve?</p>

<p>^ I and II <em>are</em> isomers because they have the same molecular formula, C2H2Cl2.</p>

<p>A bit off topic, but how would it look if I got around a 730-750-ish then retook it next year and hopefully get an 800?
:I’m going to be a senior, do I have any more test taking chances next year?</p>

<p>No, you have to recall that double bonds and single bonds differ in isomers. Google double bond isomers.</p>

<p>The only way for the double bonds to be isomers in the question given is if it were:</p>

<p>Cl H C=C H Cl</p>

<p>with Cl on top left, H on bottom left, H on top right, Cl on bottom right.</p>

<p><a href=“double bonds and isomers? - Google Search”>double bonds and isomers? - Google Search;

<p>Thanks fiftyeight,</p>

<p>For the 14.7 question I think I got 1.47</p>

<p>No I just realized that it wasn’t Tin that was the oxidation one…since it was 4s23d2, it was Ti (titanium) which has an oxidation number of +4 compared to zinc which is +2.</p>

<p>Unless there was another option that was Tin…which is like 5p2</p>

<p>How did the various prep books preform on this test?</p>

<p>What do you mean by that mabsjenbu123</p>

<p>

</p>

<p>Check the link I posted. Stereoisomers are only one type of isomer. Since both had the same formula, but different structures like you are saying, it is not stereoisomerism but is still structural isomerism. For chem at the SAT level, look ONLY at the molecular formula to determine isomerism.</p>

<p>What was the 14.7 question?</p>

<p>Could someone please tell me what the 14.7 answer is referring to?</p>

<p>Guys,</p>

<p>Does oxidation state for any element (by itself) always = 0 ?</p>

<p>The answer was 1.47 but i don’t remember what it was…I had to multiply 14.7 (maybe it was the molar mass?) by 0.1 (maybe the moles?)</p>

<p>@dwarf
Only if it’s a pure metal or a diatomic molecule.</p>

<p>

</p>

<p>I’m pretty sure the Cls were on different carbons in I and on the same one in II.
Wait, are we allowed to discuss these?</p>

<p>Edit: Here, this should finally clear it up.</p>

<p><a href=“http://en.wikipedia.org/wiki/Dichloroethene[/url]”>http://en.wikipedia.org/wiki/Dichloroethene&lt;/a&gt;&lt;/p&gt;

<p>There are two different isomers of 1,2Dichloroethene. However, there are THREE isomers of Dichloroethene. There’s also 1,1 Dichloroethene, which IS an isomer of 1,2 Dichloroethene and vice versa.</p>

<p>Actually, bob, you might be right. I’m not sure anymore, unless I can see the exact test question ._.</p>

<p>by pure metal, do you mean all the elements on the periodic table (left to the zigzag ladder) all have oxidation state of 0 when by itself right?</p>