同温同压下，质量忽略不计的两气球A和B，分别充入X气体和Y气体，且充气后两
气球的体积相同。若相同条件下，A气球放在CO中静止不动，B气球放在O2中上浮。下列叙述或表示正确的是( )
| A．X气体的相对分子质量比Y气体的相对分子质量大 |
| B．X可能是C2H4，Y可能是CH4 |
| C．X气体的密度小于Y气体的密度 |
| D．充气后A气球质量比B气球质量大 |
相关试题
Charles was alone at home, with_______ looking after him.
| A．someone | B．anyone | C．not one | D．no one |
It is often ______ that human beings are naturally equipped to speak.
| A．said | B．to say | C．saying | D．being said |
I can’t leave. She told me that I ______ stay here until she comes back.
| A．can | B．must | C．will | D．may |
—— Do you mind my opening the window? It’s a bit hot in here.
—— ______ , as a matter of fact
| A．Go ahead | B．Yes, my pleasure |
C．Yes, I do | D．Come on |
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