What type of molecule has the highest average speed in a room filled with gases?

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SUMMARY

The discussion centers on determining which gas molecule has the highest average speed in a room filled with oxygen (O2), nitrogen (N2), water (H2O), and carbon dioxide (CO2). The conclusion is that water (H2O) has the highest average speed due to its lower molar mass of 18 g compared to the other gases. The relationship between molecular speed and mass is defined by the equation 1/2 mv^2 = 3/2 kT, indicating that lighter molecules move faster at a constant temperature.

PREREQUISITES
  • Understanding of the kinetic molecular theory of gases
  • Familiarity with molar mass calculations
  • Knowledge of the equation 1/2 mv^2 = 3/2 kT
  • Basic principles of gas behavior at constant temperature
NEXT STEPS
  • Study the relationship between molecular mass and speed in gases using the kinetic molecular theory
  • Learn about the implications of temperature on gas behavior
  • Explore the concept of root mean square speed of gas molecules
  • Investigate real-world applications of gas laws in various scientific fields
USEFUL FOR

Students studying chemistry, particularly those focusing on gas laws and molecular behavior, as well as educators looking for clear explanations of kinetic theory principles.

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Homework Statement



The gases in this room include oxygen (molar
mass 32 g), nitrogen (28 g), water (18 g), and
carbon dioxide (44 g). Which type of molecule has
the highest average speed?

A) O2
B) N2
C) H2O
D) CO2
E) They have the same average speed.

Homework Equations



1/2 mv^2 = 3/2 kT

The Attempt at a Solution



Is the answer water because it's mass is the smallest?
 
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The molecular speed of gases at constant temperature varies inversely with the square root of the molecular mass. So the lightest molecule will go the fastest.
 
Thanks for replying. Sorry if it seemed obvious - I'm doing review problems without looking at the answers.
 

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