Question

1.00 mole of gaseous water (H2​O) and 1.00 mole of gaseous carbon dioxide (CO2) both have the same kinetic energy at 100.0ºC because gas kinetic energies depend on absolute temperature.

How do their average molecular velocities compare, given urms = √(3RT/Mwt)?

Mwts: H = 1.0 g; C = 12.0 g; O = 16.0 g

Question 1Select one:

a.
Their average molecular velocities are also equal.


b.
The water average molecular velocity is larger than the carbon dioxide average molecular velocity.


c.
The carbon dioxide average molecular velocity is larger than the water average molecular velocity.


d.
There is not enough information to answer this question.

Answer 1

To compare the average molecular velocities, we can use the equation:
urms = √(3RT/Mwt)

The formula shows that the average molecular velocity is inversely proportional to the square root of the molecular weight (Mwt).

Since carbon dioxide (CO2) has a higher molecular weight (44 g/mol) compared to water (H2O) (18 g/mol), the water average molecular velocity will be larger than the carbon dioxide average molecular velocity.

Therefore, the correct answer is: b. The water average molecular velocity is larger than the carbon dioxide average molecular velocity.