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- Feb 11, 2012
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AAMC 9 #142 (discrete)
When muscles in the skin contract and cause teh hair of an animal to "stand on end," the skin could be functioning as a regulator of:
A) pH
B) salt excretion
C) body temperature
D) muscle tone
I'm not sure I understand the answer for this one. How does hair standing up limit heat loss from the body? I thought it was just when you were scared or something.
The answer said something about making some kind of insulation of air. I'm not sure I follow. What does that mean? And how does that help?
AAMC 5 #24
When a strip of Cu is placed into H2O (l), no change is observed. However, when a strip of Cu is placed into a solution of HNO3(aq), a gas evolves. What is the most likely identity of the gas?
A) NO(g)
B) CO2(g)
C) H2(g)
D)O3(g)
This one is just wierd. I'm pretty sure EVERYONE who took that test when it was released picked H2 (g) for this answer. I'm assuming the fact that the copper didn't react with water is what eliminates this answer choice? But there are only very small amounts of available H+ in nuetral non-acidic water. This could just as well be the reason.
The only one I could clearly eliminate is CO2 for obvious reasons. But the others?
How does O3 formation mean copper gained an electron? And why does Kaplan say that O3 oxygen has an oxidation number of 0? Only one of the oxygens should have a 0 oxidation number. The other two should have +1 and -1 by my calculations.
And maybe I'm thinking to orgo-y but I can't think of any reasonable mechanism for the formation of NO from the reactants (or O3 for that matter) while such a mechanism is clear to see for H2 formation.
When muscles in the skin contract and cause teh hair of an animal to "stand on end," the skin could be functioning as a regulator of:
A) pH
B) salt excretion
C) body temperature
D) muscle tone
I'm not sure I understand the answer for this one. How does hair standing up limit heat loss from the body? I thought it was just when you were scared or something.
The answer said something about making some kind of insulation of air. I'm not sure I follow. What does that mean? And how does that help?
AAMC 5 #24
When a strip of Cu is placed into H2O (l), no change is observed. However, when a strip of Cu is placed into a solution of HNO3(aq), a gas evolves. What is the most likely identity of the gas?
A) NO(g)
B) CO2(g)
C) H2(g)
D)O3(g)
This one is just wierd. I'm pretty sure EVERYONE who took that test when it was released picked H2 (g) for this answer. I'm assuming the fact that the copper didn't react with water is what eliminates this answer choice? But there are only very small amounts of available H+ in nuetral non-acidic water. This could just as well be the reason.
The only one I could clearly eliminate is CO2 for obvious reasons. But the others?
How does O3 formation mean copper gained an electron? And why does Kaplan say that O3 oxygen has an oxidation number of 0? Only one of the oxygens should have a 0 oxidation number. The other two should have +1 and -1 by my calculations.
And maybe I'm thinking to orgo-y but I can't think of any reasonable mechanism for the formation of NO from the reactants (or O3 for that matter) while such a mechanism is clear to see for H2 formation.
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