FL 6, C and P #27

faceAI
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Joined: Tue May 08, 2018 1:12 am

FL 6, C and P #27

Postby faceAI » Tue May 08, 2018 1:15 am

Measurements are made in two arteries with the same diameter and the same flow rate. One artery is in the head and the other is in the leg. In a person standing upright, which of the following statements is true?
Answer is
D. The pressure of the blood in the leg is greater than the pressure of the blood in the head.

It makes common sense, but the explanation doesn't help me scientifically understand what is happening. PE = KE? But where does pressure come into place?

Thanks!
faceAI
Posts: 2
Joined: Tue May 08, 2018 1:12 am

Re: FL 6, C and P #27

Postby faceAI » Tue May 08, 2018 2:55 am

C and P #29

Which of the following compounds would have the highest melting point?

A. n-octane (correct)


B. 2,3-dimethylhexane


C. 2,4-dimethylhexane


D. 3-ethyl hexane

I was under the impression that branching increases MP as the added branches make the molecule's shape more compact and easier to stack into a solid. Whereas branching decreases BP because of reduced surface area for intermolecular forces. Wouldn't n-octance have a higher BP, but low lower melting point compared to branched compounds?
NS_Tutor_Katelyn
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Re: FL 6, C and P #27

Postby NS_Tutor_Katelyn » Thu Jun 07, 2018 4:34 pm

faceAI wrote:Measurements are made in two arteries with the same diameter and the same flow rate. One artery is in the head and the other is in the leg. In a person standing upright, which of the following statements is true?
Answer is
D. The pressure of the blood in the leg is greater than the pressure of the blood in the head.

It makes common sense, but the explanation doesn't help me scientifically understand what is happening. PE = KE? But where does pressure come into place?

Thanks!


The artery in the head has a greater gravitational potential energy than the artery in the leg, due to its higher height. So when the blood in the head descends, we have to ask ourselves what happened to that potential energy? Our normal first instinct might be that it’s converted into a faster velocity of blood flow (kinetic energy), but the question tells us that the two arteries have the same diameter and flow rate, meaning they must also have the same velocity and kinetic energy. The only other option is that the energy is being converted into a greater kinetic energy of the molecules themselves, which will result in more collisions between the molecules and more pressure. This can be tough to visualize, so let me know if that makes sense!

-Kate
Katelyn Sawyer
Senior Tutor
katelyn@nextsteptestprep.com
NS_Tutor_Katelyn
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Joined: Wed May 30, 2018 11:51 am
Location: Minnesota
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Re: FL 6, C and P #27

Postby NS_Tutor_Katelyn » Thu Jun 07, 2018 4:36 pm

faceAI wrote:C and P #29

Which of the following compounds would have the highest melting point?

A. n-octane (correct)


B. 2,3-dimethylhexane


C. 2,4-dimethylhexane


D. 3-ethyl hexane

I was under the impression that branching increases MP as the added branches make the molecule's shape more compact and easier to stack into a solid. Whereas branching decreases BP because of reduced surface area for intermolecular forces. Wouldn't n-octance have a higher BP, but low lower melting point compared to branched compounds?


I’m not quite sure where you’re looking, I went to the question 29 of the first section of full length 6, but it doesn’t seem to match your question. Are you sure that’s the right one?
Katelyn Sawyer
Senior Tutor
katelyn@nextsteptestprep.com

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