<p>acid can be characterized by
I. hydrogen ion donor
II. proton donor
III. electron donor</p>
<p>i'm not sure if i remembered the answers correctly, but i remermber getting I and II. is that right?</p>
<p>I'm 100% sure that the water/hydrogen bond one is T,F</p>
<p>Hydrogen bondsing DOES NOT explain why ice is less dense than water, it only explains that water has high specific heat and strong intermolecular forces.</p>
<p>The reason is that: if you look at the phase diagram of water, you will find that the slope of solid-liquid border is NEGATIVE, and this means that as temperature decreases, the pressure increases. Therefore solid water is more dense than liquid water.</p>
<p>On the other hand, for CO2, the slope of solid-liquid border is positive, and this meansthat liquid is more dense than solid for CO2</p>
<p>ahhh, yes the answer for that one was I and II</p>
<p>For skierdude1000 the ativation is T,T,CE; the first statement is correct because the reaction of A-->B has a much lower activation energy than the reverse reaction of B-->A. Since a reaction needs to conquer activation energy barrier, the lower the activation energy, the faster the reaction.</p>
<p>For ahhh, the yes, the answer is (I) and (II)</p>
<p>Actually, I think the density question is because of the open structure of the hydrogen bonding. Check out the above site. It even has a sentence explanation at the bottom of the graphic. And this site has a better explanation:</p>
<p><a href="http://www.bluedevilchem.com/info/water.htm%5B/url%5D">http://www.bluedevilchem.com/info/water.htm</a></p>
<p>But they both say that the open structure makes ice less dense than water. Therefore, the answer was T,T,CE</p>
<p>Here from my chem book (General Chem by Petrucci):
"the model for ice in fig 11.21 shows how hydrogen bonds break, and water molecules move into holes that were in the ice structure. As a result, water molecules are closer tether in liqwuid water than in ice. when ice melts there is a 10% decrease in volume and corresponding increase in density. liquid watera t o celsius is MORE DENSE than ICE, but water is most unusual in this case. for the vast majority of substances, the liquid state is LESS DENSE than the solid. HIGH PRESSURES FACILITATE THE DISRUPTION OF HYDROGEN BODNING AND THE DECR4EASE IN VOLUME THAT ACCOMPANY THE MELTING OF ICE. THUS THE GHREATER THE PRESSURE THE LOWER THE TEMPERATURE AT WHICH ICE AN MELT. THIS ACCOUNTS FOR THE NEGATIVE SLOPE OF THE FUSION CURVE.... if we continure to heat liquid water abpve melting point, more hydrogen bonds break"</p>
<p>yes, the phase diagram does support this, but it is NOT a reason. its just a quantative representation (graph) of what happens at a molecular level. hydrogen bonding accounts for the negative slope.</p>
<p>and you will see why the answer is T,F because it has something to do with the phase diagram and the negative slope</p>
<p>lol, yes the phase diagram is correct. but a graph isn't an explanation. it is just something scientists create to make things concrete. </p>
<p>if u read what i wrote, it explains it, and how the hydrogen bonding causes the graph to be made that way.</p>
<p>"THUS THE GHREATER THE PRESSURE THE LOWER THE TEMPERATURE AT WHICH ICE AN MELT. THIS ACCOUNTS FOR THE NEGATIVE SLOPE OF THE FUSION CURVE."</p>
<p>the explanation goes deeper than the graph....</p>
<p>for tm2000, I can buy that...yeah, now I see why hydrogen bond is right</p>
<p>For the one I put graduated cylinder becuase the question ask to which one can MEASURE AND TRANSFER the testing VOLUME most accurately.</p>
<p>I don't think buret is right because you cannot use buret to transfer liquid.</p>
<p>Any thought?</p>
<p>I was confused on that one, but I put buret. Because I thinking by controlling the buret you are transferring the liquid from the buret into the other solution. And a buret does have measurements on it, so you can measure the volume of the substance that you put into the titration.</p>
<p>well, i don't remember what the questions actually said, but a buret is the the long skinny thing that u use to add acid/base to base/acid or whatever. it definitely has markings on it, for you need to know how much of whatever ever u are adding to something else. remember a buret is for titrations, u must know the volume to calculate a titration. i also thought that implied transfering. </p>
<p>but one of them included ''stop ****'' and valve''. for sure, a valve is used on a buret, and definitely not a graduated cylinder. the valve allows for careful addtion of substance to something elese. and also, i dont think a stopcock can be put on a graduated cylinder, or for what purpose it would serve?</p>
<p><a href="http://www.uigi.com/air.html%5B/url%5D">http://www.uigi.com/air.html</a> <- this site proves the answer is H2 not H2O for least present in air, since H20 can be present anywhere between 0 and 5%, which is alot more compared to the trace amounts of H2 shown on that other site.</p>
<p>hahahaha it censored c-o-c-k. lol, thats great.</p>
<p>yea except it is 0-5% INCLUSIVE. and the test said specifically ''under normal conditions.'' why else would it say that with the answer choices there? all the answer choices were things that are always present in air, not ''non standard'' things like SO2 which YOUR site states. ur site also says that you need certain conditions. the ''standard '' chart at the top of the page does not include water!</p>
<p>i do not think the SAT2 makers expected us to know relative amounts of elements in air. they wanted us to use common sense, thus the ''normal conditions'' thing that was stated in the problem.</p>
<p>well, i think it makes sense that H2 is least amount in air. and if you want to take the phrase literally, normally there is almost always water vapor in air. it never said "standard dry air.' Even in CA. (i.e. weather forecasts ALWAYS talk about humidity)</p>
<p>also, what about the problem where the explanation was something like ordered reactions are less probable than unordered?</p>
<p>EDIT: (from wikipedia) </p>
<p>"Under normal atmospheric conditions, water vapor is continuously evaporating and condensing. Normally, water vapor is invisible to the naked eye."</p>
<p>if H2 was copius in air, we would all blow up every time we smoked!!</p>
<p>how many Raw Points do i need to get 700 from Real SAT II's?</p>
<p>wow...just read two pages of this thread straight..soo dizzy -__-...
so the answer is H2? i put H2 instead of H20 b/c i thought water vapor was present always...normal conditions would signify what? 0 C and 1atm? </p>
<p>and i also got two burets for my answers...one with the control and stopcock, and the other for measuring the volume for titrations b/c i've done lots of titrations in chem lab and we never use graduated cylinder</p>
<p>i thought to measure volumes for titrations you use the volumetric flask</p>
<p>Does anyone have the Real SAT II book???</p>
<p>can you read me ot the raw points you would need to get 700 from several tests??</p>