Hey im having some problems with some thermodynamics yet again. Check these out:(adsbygoogle = window.adsbygoogle || []).push({});

1) A welder using a tank of volume V fills it with oxygen (with a molar mass of M) at a gauge pressure of [tex]p_1[/tex] and temperature of [tex]T_1[/tex]. The tank has a small leak, and in time some of the oxygen leaks out. On a day when the temperature is [tex]T_2[/tex]. , the gauge pressure of the oxygen in the tank is [tex]p_2[/tex].

A)Find the initial mass of oxygen.

Use R for the ideal gas constant and [tex]p_a[/tex] for atmospheric pressure.

B)Find the mass of oxygen that has leaked out.

I know this is a simple one but dont see hwo to set it up. will it be something like the difference of the initial and finals or something? i was tryin to work with the equation pV=nRT

2) Initially, the translational rms speed of an atom of a monatomic ideal gas is 250m/s. The pressure and volume of the gas are each doubled while the number of moles of the gas is kept constant.

What is the final translational rms speed of the atoms?

Well i was looking at the equations for RMS and all require T so how would i got about this problem?

3) The ideas of average and root-mean-square value can be applied to any distribution. A class of 150 students had the following scores on a 100-point quiz:

Score/ Number of Students

10/ 11

20 / 12

30 / 24

40 / 15

50 / 19

60 / 10

70 / 12

80 / 20

90 / 17

100 / 10

A) a asks to find the average score of the class which i ws able to do but part b asks for the root-mean-square of the class....what i tried was something like (10*11)^2+(20*12)^2+..... all divided by 150 and taking the square root of this result....im getting it wrong though, does anyone see where im mkaing my mistake.

I have some others but i think that getting and understanding these would help me figure out the others....thanks for any help and patience

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Thermodynamics HELP

**Physics Forums | Science Articles, Homework Help, Discussion**