<p>guys there was a friggin history question about how "mendeleev could predict physical properties of Ga" ...LOL... i put FF because the periodic relationships relate chemical properties, not physical properties..</p>
<p>No I know. Octet rule never works for boron. But technically boron trioxide isn't really boron trioxide. Its a complex of BO3 rings and chains. Based on the chemistry you should know for this test, then boron which we know doesn't follow an octet cannot make discrete B2O3 molecules (which is technically true since that's not the form B2O3 exists in), So I'd be extremely surprised if that's what they were expecting you to know unless they were testing whether you just knew it existed not on whether you understood bonding.</p>
<p>Idk whether Mendeleev predicted the properties of gallium. However I do know periodic trends do tell us physically properties too. We know if something is a metal versus a nonmetal based on position on the periodic table and those have vastly different and predictable physical properties.</p>
<p>Boron</a> trioxide - Wikipedia, the free encyclopedia</p>
<p>B2O3 does exist, i put B and Fe</p>
<p>I know it exists. But again it's not B2O3 as in a molecule consisting of 2 borons and 3 oxygens. Its a huge complex of long chains of borons and oxygens whose empirical formula reduces to B2O3. You can't know this from what you learn in a regular high school chemistry class (including AP) so I don't think they're asking about that. There are a lot of things in chemistry that we're told do or don't exist that aren't the case once you get into more advanced topics but that's not what this test tests you on. I could be wrong in thinking that but I don't see why they would test you on those type of compounds.</p>
<p>well they wouldn't expect us to know that, i think the purpose of that question was to test you on how different elements bond based on their valence electrons, so since Fe (III) and B have the same number of valence electrons, then this is what they'd want us to answer, even if in reality the answer should be different.</p>
<p>But boron is a nonmetal so you should know nonmetals don't bond the same way as metals. </p>
<p>Whatever. I hate ambiguous questions. I thought that was confined to the realm of the literature test =/</p>
<p>oh wth was i thinking. yeahhhh, to what i said like a page ago, a hydride is the answer to that one lol.</p>
<p>mehhhh, i failed though. i got three of the separation ones wrong and prolly like 2 or 3 others, so ima cancel -____-</p>
<p>I can actually remember some calculation qs from the top of my head- the one with the amount of heat loss was it -9.25 or sumthin along the lines?</p>
<p>I totally agree with Sifat.</p>
<p>Here is some colclusive stuff, how i solved the B2O3....I looked which group B was in, and it was the same as that of alluminium, so i put in B2O3, as Al2O3 exists!</p>
<p>^ I don't remember this question... what was it again?</p>
<p>
Lol seriously? As if it matters if you get an 800 or not...</p>
<p>a halide contains a halogen...right? i think metal and hydrogen is a hydride</p>
<p>the heat loss was around that i think</p>
<p>are you sure the test said physical properties instead of chemical properties?</p>
<p>It doesn't matter... elements in similar groups have similar physical properties, too. Like how alkali metals are whitish and stuff.</p>
<p>What maximum wrong could we get to still have an 800 in Chem ? I am really worried about TFCE part in Dec SAT. A lot of weird questions !</p>
<p>Probably a max of 4-5 wrong.</p>
<p>I got around that many wrong and got an 800 :)</p>
<p>Wow, the vast majority of answers I've seen posted here are really, really wrong. Mendeleev did predict the existence of Ga, that was true, the second part was false because elements that have the same number of valence electrons have similar chemical properties.</p>
<p>And if you think insulated does not imply closed.... lol. Explain how you can have an insulated container that isn't closed? Have you ever done any calorimetry in lab?</p>
<p>Halide = halogens
Hydride = metal + hydrogen</p>
<p>B and Fe</p>
<p>Edit: Definition of "closed system": closed system -- a system with a boundary permeable to energy but not to mass. Insulated, no?</p>
<p>Erm I would like an answer for a score prediction. I didn't read through this thread so I have no idea what I put for the trickier questions. In general I'm pretty confident I destroyed the test, but I had four omits because of time restraints. As all of you understand 85 questions in an hour is a lot. So I'm slightly worried about what score I will receive. This is the third time I've taken the Chemistry SAT II. I would prefer not to take it again as junior year is hectic etc. </p>
<p>So how is the curve?
On my practice tests since my last actual collegeboard test of 700 were: 590, 590, 640, 680, 700, 740, 770. I'm pretty sure I would have gotten an 800 on the last practice test, but I didn't take one so...</p>
<p>For those of you who don't know scores are released December 25, 2008 (Christmas Day OMO)</p>
<p>Scores come out on the 23 dude.</p>