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 [URL]http://upload.wikimedia.org/math/4/3/f/43fa535941b0be935b3b173e1ce20338.png[/URL] 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.