NEED ANSWERS FASTTTTT: 10 points B.A?

Question

So, i asked this question before, and ppl were just idiots.

I have the August 2008 Chemistry Regents tomorrow. so if anyone knows the EXPLANATIONS (i already have all the answers) to these questions, please please answer them. Thanks in advance!

June 2006 Regents: #19, #22

http://www.jmap.org/JMAP/IJMAP/Chemistry...

August 2006 Regents: #16, #39, #43, #79

http://www.jmap.org/JMAP/IJMAP/Chemistry...

January 2006: #30

http://www.jmap.org/JMAP/IJMAP/Chemistry...

ALSO: if you have an email address I could reach you at just till tonight (my test is tomorrow...) that would be absolutely SPLENDID! Just so I could ask you questions, I'm not a stalker lol.

Thanks again! :)

*little miss fashionista

Answer 1

i have the explanations and i am taking the test today too but if u can send me at [e-mail] the answers for the aug regents 2008 and i will wait online for your message.

thank you

Answer 2

Your links don't go anywhere

Edit: I got the links from your other question.

19: There are some answers we can rule out right away. 1 and 2 are clearly combustion reactions (carbon-molecule + O2 --> CO2), so they're exothermic. For 3, we can see that the total moles of gas in the system goes down, meaning that the products would, given constant volume, have a lower temperature, and the reaction would be exothermic.

22: 4 is appropriate here, because all the other choices are physical or chemical properties, which usually are not the same for two isomers. In fact, the only thing that must be the same for them is molecular formula, which is the written out ratio of each atom in the molecule, regardless of its structure.

16: The pathway must be alternate, because identical pathways require identical energetics. In addition, it must be a lower activation energy, because that is what allows the reaction to proceed more easily. Less energy is required to get the desired result.

39: The heat of fusion of water is roughly 6 kJ/mol and water is 18g/mol, so 6 kJ/mol x 30g / 18g/mol = 10 kJ = 10000 J.

43: Weak bonds must be involved, because high pressure is required. The stronger the bonds, the lower pressure and higher temperature needed to liquefy or freeze a substance. Covalent bonds cannot have anything to do with it, because chlorine gas is Cl2 as well as liquid chlorine, meaning that the covalent bonds do not change.

79: The clue here is that you're trying to create ethyl methanoate. The ethyl means that it would be ethyl alcohol.

30: Ionic compounds depress the freezing point of aqueous compounds because they introduce ions that disrupt the crystal formation required for ice. The more ions, the lower the freezing point drops, meaning that CaCl2 (3 ions) has a lower freezing point than KCl (2 ions).