<p>Hi everyone!</p>
<p>Ok, I have a slew of chemistry questions to ask you guys. My test is Dec. 2, so I would really, really appreciate it if you guys could take some time and look at them. I know there are a lot, so please don't feel like you have to answer them all - I would appreciate any answers. I've given some page references for Barron's SAT Chemistry 2007 if that will help you. I know some of the questions are very elementary, but I really want to clarify all the things I am not sure about, so please bear with me...and please help me and other chemistry test-takers out! :) Thank you!!</p>
<p>1) Which is the more reactive fluorine or francium? (I know that F is the most reactive nonmetal, and Fr is the most reactive metal).</p>
<p>2) Are electrostatic bonds considered intermolecular forces of attraction?</p>
<p>3) Minimum repulsion between two electron pairs in a molecular compound will result in a linear structure This statement is TRUE. I thought it was false though because I thought repulsion would be maximum since the electron pairs would be 180* apart, the furthest possible.</p>
<p>This statement is also TRUE. The VSEPR model says that like charges will orient themselves so as to diminish the repulsion between them. But again, I thought the repulsion would be maximized. Why am I wrong for both these statements? (Btw, the answer is TTCE just incase youre wondering)</p>
<p>4) 2K + 2H2O 2KOH + H2(g) Can O2 be a product instead of H2?</p>
<p>5) What is the 2n^2 rule for the valence electrons? (Like the first shell has 2 electrons, then 8, then 18, etc is the rule that turned out to be not right?) I remember seeing it somewhere in Barrons book and then lost it and haven't been able to find it since.</p>
<p>6) What is the difference between subshells and sublevels?</p>
<p>7) Reference page 72, Barrons: Where does the + charge on the NH4+ ammonium ion come from?? Also on this page, I do not understand the potential energy graphs at all. Would you be able to please simply explain them to me? </p>
<p>8) page 72 - London forces cause nonpolar substances like noble gases to condense into liquids, then freeze into solids because the London forces cause the particles to generally be closer together? Is that a correct explanation?</p>
<p>9) also on page 74 - what is electron density? </p>
<p>10) page 75 - resonance structures. What are they? The diagrams just seem to be rotated, and this could be done for any molecule. Nothing seems to distinguish the three sulfur trioxide structures, or the two benzene ones.</p>
<p>11) page 155 can someone please explain gram-equivalent mass and normality please?</p>
<p>12) Specific gravity essentially is just density?</p>
<p>13) Is gram-atomic mass essentially the molar mass without the moles? And same with gram-formula weight? (Also, difference between the mass in gram-atomic mass and weight in gram-formula weight?)</p>
<p>14) Definition of monoatomic on page 69 elements that show no tendency to combine with iether like atoms or other kinds of elements so I figured noble gases. BUT, on page 88, rule number 1 says The oxidation number of a monoatomic ion is the same as the charge on the ion. Therefore, in NaCl, the oxidation number assigned to sodium is +1, and the oxidation number of chlorine is -1 WHAT?! This doesnt seem to have anything to do with the original monoatomic???</p>
<p>15) Any easy way to remember solubility rules? Any mnemonic methods? </p>
<p>16) Page 159 - What is the difference between orthorhomic, triclinic, and tetragonal crystal structures? The three structures just seem to have different bases (perhaps the internal axis?) </p>
<p>17) Page 160 #11 The question asks When another crystal was added to a water solution of the same substance, the crystal seemed to remain unchanged. Its particles were: </p>
<p>A) going into an unsaturated solution
B) exchanging places with others in the solution
C) causing the solution to become supersaturated
D) not going into solution in this static condition</p>
<p>The answer was B. But my question is, how do you tell the difference between the situation in B (equilibrium) vs. the situation in C (supersaturation)? Dont the two situations look the same physically?</p>
<p>18) Do I need to memorize the activity series?</p>
<p>19) Why does the universe prefer exothermic reactions if the universe likes low energy, high entropy? Dont exothermic reactions release energy, so the energy is therefore high? Or do I have this reversed?</p>
<p>20) I am sooo bad at mental math any tips/tricks for doing square roots of numbers in scientific notation? Or dividing/multiplying/decimal places? I know for multiplying, add the exponents on the 10; for dividing, subtract the exponents but Im pretty bad with the rest. How hard does the math on the test get?</p>
<p>21) Degrees kelvin can never go negative, right? (Because then an endothermic reaction, a negative entropy level could make a negative delta G, but according to Barrons on pg. 197, that is impossible)</p>
<p>22) Is Ca(OH)2 a strong base? In PR, it is not. But it seems like Barrons is implying that it is on page 202 because it is completely or near completely ionized in water.</p>
<p>23) I think I am mixing up aqueous solutions with something else, but on page 203, under Broader Acid-Base theories, it talks about reacting HCl with NH3 to make a white solid, NH4Cl. But, according to the solubility rules all Cl compounds are soluble. However, NH4Cl isnt soluble, because it isnt in an aqueous solution, right? The questions will make sure to state that we are dealing with aqueous solutions?</p>