# Homework Help: Mutiple Choice

1. May 10, 2010

### jagged06

1. The problem statement, all variables and given/known data

Two identical vessels contain different ideal gases at the same pressure and temperature. Which of the following statements are true? (Select all that apply.)

[]The total mass of gas is the same in both vessels.
[]None of these statements are true.
[]The average speed of the gas molecules is the same in both vessels.
[]The number of gas molecules is the same in both vessels.

2. Relevant equations

3. The attempt at a solution

The answers that make the most sense to me would be The total masses are the same, and the average speeds are the same, but that isn't right. Am I missing something important?

The answer could be multiple boxes.

Last edited by a moderator: Apr 25, 2017
2. May 10, 2010

### jagged06

anyone have any ideas?

3. May 10, 2010

### Redbelly98

Staff Emeritus
The ideal gas law would be helpful here.

4. May 11, 2010

### jagged06

Added the ideal gas law and looked at the problem again, but I'm still not sure.

5. May 11, 2010

### bjd40@hotmail.com

here p,v and t are same and that implies n is also same for both the gases. now think what is n? i think that will help u.

6. May 11, 2010

### jagged06

If n is the same, then they would have the same number of moles. But does that mean that their masses are the same? as in:

[x]The total mass of gas is the same in both vessels.
[]None of these statements are true.
[]The average speed of the gas molecules is the same in both vessels.
[x]The number of gas molecules is the same in both vessels.

or is it just the number of gas molecules is the same?

[]The total mass of gas is the same in both vessels.
[]None of these statements are true.
[]The average speed of the gas molecules is the same in both vessels.
[x]The number of gas molecules is the same in both vessels.

I've only got one more shot at this question so I want to make sure I am right, but the second one makes the most sense to me. If mass is in grams, different gasses could have the same number of molecules but different masses. correct me if i'm wrong.

7. May 11, 2010

### sjb-2812

Sounds good to me, regardless of what you measure mass in, grams, ounces, ton(ne)s, ...