physics

posted by .

The speed of propagation of a sound wave in air at 27 degrees Celsius is about 350 m/s. Calculate, for comparison, v_rms for nitrogen (N2) molecules at this temperature. The molar mass of nitrogen is 28.0 g/mol.

• physics -

You will find the two velocites to be roughly the same.
The mean kinetic energy of the molecules is
Eav = (3/2) kT = 6.21*10^-21 J
That equals (1/2) M V^2 (where V is the rms average).
M = (28.0 g/mole)/[(6.02*10^23 molecules/mole)* 1 kg/1000 g]
= 4.65*10^-26 kg/molecule
V^2 = 2 Eav/M = 2.67*10^5 m^2/s^2
Vrms = sqrt V^2 = 517 m/s

Check my reasoning and numbers.

• physics -

The speed of sound is always less than the rms speed, by a factor
sqrt(gamma/3). Gamma, the specific heat ratio Cp/Cv, equals 1.4 for diatonic gases

Similar Questions

1. Chemistry

350 calories of heat is added to a sample of nitrogen gas, and the temperature is increased by 89 degrees celsius. what is the mass of the sample of nitrogen gas?
2. physics

Calculate the mass of nitrogen present in a volume of 3000 cm^3 if the temperature of the gas is 22 degrees Celsius and the absolute pressure is 2.00 * 10^-13 atm, a partial vacuum easily obtained in laboratories. The molar mass of …
3. Physics - Sound Energy propagation

Sound, a form of energy can be modeled by using two distinctly different approaches. a) Describe the propagation of sound energy through air by discussing the motion of individual particles. Include possible mathematical equations …
4. writting a program

Speed of Sound. Sound travels through air as a result of collisions between the molecules in the air. The temperature of the air affects the speed of the molecules, which in turn affects the speed of sound. The velocity of sound in …
5. chemistry

350 calories of heat is added to a sample of nitrogen gas and the temperature is increased by 89 degrees Celsius. What is the mass of the nitrogen sample in cal/gram Celsius?
6. physics

The speed of sound in air varies with the temperature and humidity of the air. In dry air at 20 degrees Celsius, the speed of sound is approximately 343 m/sec. A closed tube resonates with a node at each end for a sound wave in air. …
7. physics

Suppose that, on a day when the outside temperature is 15 degrees Celsius, we fill a balloon with pure nitrogen gas, of which the molar mass is 28 grams per mole. Now suppose that we want to heat up a second (equally large) balloon …
8. Physics

A gas cylinder has a volume on 200l, and contains Nitrogen at a pressure of 200kPa and a temperature of 290 degrees Kelvin. The molar mass of Nitrogen is 14.0067g. Calculate. The number of moles in the gas cylinder?
9. Science

The difference between the speed of sound in air at 0 degrees Celsius and the speed of sound in air at 20 degrees Celsius is that A) cooler air molecules move more slowly and respond less readily to the energy of a sound wave B) cooler …
10. College Physics

At what temperature is the root-mean-square speed of nitrogen molecules equal to the root-mean-square speed of hydrogen molecules at 126 oC?

More Similar Questions