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RMS Speed Questions

Standard Temperature and Pressure (STP) is:

pressure of 1 atmosphere = 1.01 x 105 Pa

temperature of 0°C = 273K

At STP 1 mole of ideal gas occupies 22.4 litres = 22.4 x 10-3 m3

 

Q1. Calculate the RMS speed of air molecules in a container in which the pressure is 1.0 x 105 Pa and the density of air is 1.3 kg m-3.

Q2. The following table shows the distribution of the speeds of 20 particles:

Speed/ms-1 10 20 30 40 50 60
Number of particles 1 3 8 5 2 1

 

Find

(a) the most probable speed,

(b) the average speed,

(c) the RMS speed.

Q3. The RMS speed of helium at STP is 1.30 km s-1. Calculate the density of helium at STP.

Q4. The RMS speed of nitrogen molecules at 127oC is 600 ms-1. Calculate the RMS speed at 1127oC.

Q5. If the density of nitrogen at STP is 1.25 kg m-3, calculate the RMS speed of nitrogen at 227 °C.

Q6. Calculate the temperature in degrees Celsius at which the RMS speed of oxygen molecules is twice as great as their RMS speed at 27 °C.