Exam Krackers

[Juggernauts]

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I am going through some exam krackers problems from the 2005 print of 1001 questions for MCAT in General Chemistry. (just wanting some extra practice). Came across a simple problem.

Asking for the ratio of average speed of an ATOM of neon to a MOLECULE of Hydrogen at the same temp and pressure.

R1/R2 = sqrt M2/M1
Ne/H = sqrt 1/20
Answer should be 4.5:1

Answer provided is 1:3.2

I believe this problem is jacked based on the fact that answer should be in sequence of Neon first : then Hydrogen.

However, it looks they used the ATOMIC number of neon instead of the molecular weight. Anyone ever seen a problem worded like this? And am I missing something on the phrasing. Just because it says Atom of neon does not change anything about the equation setup. I know there are some gen chem genius's out there, so please enlighten me.

If anyone has the book, its problem 193.

Thanks in advance.

 

[wall1two]

first i dont see anything wrong with the way you did the problem at all. that is 100% how i would have done it. all i can think of is that that formula is for rates of effusion compared to each-other. the average velocity of a gas with the same tempretures can either be done by KE (which they all are equal in respect to each other if the temp is the same) = mass*V^2

or

ave velocity = 2ndroot(3RT/MW) or 2ndroot(3KT/mass) see how those formulas work and then see how they relate.

 

[Juggernauts]

Hmmmmm...... I will check it out....... Thank u

 

[dongkookLim]

Asking for the ratio of average speed of an ATOM of neon to a MOLECULE of Hydrogen at the same temp and pressure.

R1/R2 = sqrt M2/M1
Ne/H = sqrt 1/20
Answer should be 4.5:1

Answer provided is 1:3.2

Thanks in advance.

I think the atm of Neon (Noble gas) is ~20 and H molecule (H2) = 2.
So Ne/H = sqrt(2/20) = 1/3.16.

Hope that helped.

 

[Juggernauts]

I think the atm of Neon (Noble gas) is ~20 and H molecule (H2) = 2.
So Ne/H = sqrt(2/20) = 1/3.16.

Hope that helped.

Stupid diatomic elements!!!!!!! I hate making those mistakes.... I little worried about those stupid mistakes happening on the dat. I am pretty sure that when I take my DAT, there is not going to be anything I have never seen, but those little errors can cost soooooooooo much in the big scheme of things.

Good catch, thanks...

 

[wired202808]

juggarnauts remember the 7 diatomic molecules as Never Have a Fear Of Ice Cold Beer! Nitrogen, Hydrogen, Fluorine, Oxygen, Iodine, Carbon, Bromine!

 

[Juggernauts]

juggarnauts remember the 7 diatomic molecules as Never Have a Fear Of Ice Cold Beer! Nitrogen, Hydrogen, Fluorine, Oxygen, Iodine, Carbon, Bromine!

I 😍 ice cold beer!!! I shall never forget it!!!!