AL physics about gas(2)

用戶36732

2010-09-05 8:12 am

Two vessels contain hydrogen gas and oxygen gas respectively. Both gases are assumed to be ideal and they have the same pressure and temperature. Which of the following physical quantities must be the same for the two gases?

A The volume of the gas
B The mass per unit volume of the gas
C The r.m.s. speed of the gas molecules
D The number of gas molecules per unit volume

解釋你所選既答案點解正確 & 其他答案點解錯... thx!~

回答 (1)

天同

2010-09-05 10:33 am

✔ 最佳答案

Both options A and D are correct.

This simply follows Avogadro's hypothesis, which states that" equal volume of gases under the same pressure and temperature contain equal number of molecules" .

Option B is wrong because hydrogen and oxygen molecules have different masses.

Option C is wrong because rms speed of gas molecules under a given temperature depends on the molecular mass. Heavy molecules have lower speed.

Please refer to the following web-page for the Avogadro's hypothesis:

http://library.thinkquest.org/12596/avogadro.html

2010-09-05 09:00:13 補充：
sorry...I made a mistake. Option A is also wrong. It is not given in the question that the two vessels are of equal volume. Sorry that I have overlooked this.

2010-09-05 09:01:01 補充：
The correct answer is thus Option D.

👍 0 👎 0