A gas system absorbs 200J of heat and simultaneously does 300J work on surroundings at a given temperature, what is △U in joules for the gas system?
A: +100
B: -200
C: +200
D: -100
A: +100
B: -200
C: +200
D: -100
举一反三
- DU = 100 J is for a system that gives off 100 J of heat and ( ) A: does no work B: does 200 J of work C: has 100 J of work done on it D: has 200 J of work done on it.
- A gas, while expanding absorbs 25 J of heat and does 243 J of work. What is DU for the gas? A: 268J B: -218J C: 218J D: -268J
- One mole of hydrogen with an initial temperature of 27℃ expands<br/>and in the process, absorbs 4000 J of heat and does 3000 J of work,<br/>the<br/>final temperature of the gas is () A: 62.3℃ B: 105.6℃ C: 75.1℃ D: 56.3℃
- When a system moves from A state along path I to B state, it releases heat of 100 J and obtains 50 J work at the same time; when the system does 80J work from A state along path Ⅱ to B state, then Q is（ ） A: 70J B: 30J C: －30J D: －70J
- 室颤时第二次用（）除颤。 A: 100J B: 100~200J C: 200J D: 200~300J E: 360J