Contradiction in Destoryer

[Molarcule]

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Okay so on the 2010 edition of destroyer in the Gen Chem section question 21 ask

Consider five identical 1.0L flask at 1 atm pressure and 25degree C containing Cl2, Ar, NH3, CH4, and N2. Which statement is false?
A) Cl2 flask has the highest density
B)NH3 and CH4 have the fastest velocity
C)All the gases have the same average kinetic energy
D)All gasses contain an equal number of molecules
E)All are true

The answer is E

38 ask
Which statement is false?
A)Kr has a lower average speed than Ne at the same temp
B)The molecules of a gas undergo many collisions with each other and with the walls of the container
C)Deviations from the ideal gas law are greater at low temperature and high pressure
D)All molecules of an ideal gas have the same kinetic energy at constant temp
E)All are true

The answer is D

The the question is. At the same temperature is the kinetic energy the same? One question says yes the other says no.

 

[UndergradGuy7]

They both say yes?

All the gases have the same average kinetic energy
Other question All molecules of an ideal gas have the same kinetic energy at constant temp

How are you getting one says no other says yes?

Isn't KE=3/2 nRT

So yes. Same t, same kinetic energy.

Edit: nvm, misread the which is false etc thing.

 

[vindicate]

Okay so on the 2010 edition of destroyer in the Gen Chem section question 21 ask

Consider five identical 1.0L flask at 1 atm pressure and 25degree C containing Cl2, Ar, NH3, CH4, and N2. Which statement is false?
A) Cl2 flask has the highest density
B)NH3 and CH4 have the fastest velocity
C)All the gases have the same average kinetic energy
D)All gasses contain an equal number of molecules
E)All are true

The answer is E

38 ask
Which statement is false?
A)Kr has a lower average speed than Ne at the same temp
B)The molecules of a gas undergo many collisions with each other and with the walls of the container
C)Deviations from the ideal gas law are greater at low temperature and high pressure
D)All molecules of an ideal gas have the same kinetic energy at constant temp
E)All are true

The answer is D

The the question is. At the same temperature is the kinetic energy the same? One question says yes the other says no.

same kinetic energy =/= same AVERAGE kinetic energy

 

[CANgnome]

at the same temperature, molecules have the same AVERAGE velocity, but individual velocities are distributed over a wide range of velocities.

there is a distribution in the KBB

 

[UCB05]

same kinetic energy =/= same AVERAGE kinetic energy

/nod

 

[Ibraiz]

Question 38 choice D is talking about every single molecule of gas has the same kinetic energy, which is not true. Molecules of gases have different kinetic energy even at the same temperature. Different molecules of gases move at different speed BUT the gases have the same 'Average Kinetic Energy' thus, the same average speed.

Reiterate: Different molecules of gas have different speed at the same temperature but when we average all the speed together all the gases have same average speed at the same temperature thus, same average kinetic energy at the same temperature.



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[RCT PC CRN]

Average KE vs individual KE