Question
The average kinetic energy of the molecules in a gas sample depends only on the temperature, 𝑇. However, given the same kinetic energies, a lighter molecule will move faster than a heavier molecule, as shown in the equation for rms speed
rms speed=3𝑅𝑇ℳ‾‾‾‾‾√ where 𝑅=8.314 J/(mol⋅K)
R=8.314J/(mol⋅K) and ℳ is molar mass in kilograms per mole. Note that a joule is the same as a kilogram‑meter squared per second squared (kg·m2/s2).
What is the rms speed of N2 molecules at 391 K?
rms speed=3𝑅𝑇ℳ‾‾‾‾‾√ where 𝑅=8.314 J/(mol⋅K)
R=8.314J/(mol⋅K) and ℳ is molar mass in kilograms per mole. Note that a joule is the same as a kilogram‑meter squared per second squared (kg·m2/s2).
What is the rms speed of N2 molecules at 391 K?
Answers
rms speed = sqrt (3RT/M). Just substitute the number is the problem.
You're given R, T, and M.
You're given R, T, and M.