Physics 410 Spring 2010 HW#2
Due Friday, 8 February 2010
1. Determine the number of collisions air molecules make on a 1 cm2 area of your skin in one second at standard temperature and pressure (T = 273.15K, P = 101,325 Pa). If you need to, you may assume all air molecules have a mass equal to the average mass of an air molecule. The molar mass of an average air molecule is 28.8 g/mol.
2. You have several identical balloons. You experimentally determine that a balloon will break if its volume exceeds 0.900 liters. The pressure of air inside a balloon is always very nearly equal to atmospheric pressure (1 atm). If the air inside the balloon is at a constant temperature of 22.0oC and behaves like an ideal gas, what mass of air can you blow into one of the balloons before it bursts? Repeat the calculation for helium.
3. Calculate the rms velocity of He atoms at 2K, nitrogen molecules at 27oC, Hg atoms at 100oC, electrons at 1000K, and electrons at 10,000K.
Physics 410 Spring 2010 HW#2
Due Friday, 8 February 2010
1. Determine the number of collisions air molecules make on a 1 cm2 area of your skin in one second at standard temperature and pressure (T = 273.15K, P = 101,325 Pa). If you need to, you may assume all air molecules have a mass equal to the average mass of an air molecule. The molar mass of an average air molecule is 28.8 g/mol.
2. You have several identical balloons. You experimentally determine that a balloon will break if its volume exceeds 0.900 liters. The pressure of air inside a balloon is always very nearly equal to atmospheric pressure (1 atm). If the air inside the balloon is at a constant temperature of 22.0oC and behaves like an ideal gas, what mass of air can you blow into one of the balloons before it bursts? Repeat the calculation for helium.
3. Calculate the rms velocity of He atoms at 2K, nitrogen molecules at 27oC, Hg atoms at 100oC, electrons at 1000K, and electrons at 10,000K.