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: 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.
举一反三
- If the expansion work w = -15 J, it indicates that the work is done on the surroundings.
- 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
- 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
- She much work recently. A: have done B: did C: does D: has done
- Work is taken negative when the work is done by the system and heat is taken as positive when it is transferred into the system. （ ）