Fill in the blanks in the following paragraph to correctly identify the signs associated with heat and work.

When a system is heated, heat is _______________ by the system. The amount of heat added is given a _______________ sign. When a system is cooled, heat is _______________ by the system. The amount of heat is given a _______________ sign. If a gas expands, it must push the surrounding atmosphere away. Thus, work is done _______________ the system and is given a _______________ sign. If a gas is compressed, then work is done _______________ the system. This work is given a _______________ sign.
e. What is the change in internal energy if 50 J of heat are released from a system, and the system does 80 J of work on its surroundings?

Question

Fill in the blanks in the following paragraph to correctly identify the signs associated with heat and work.

When a system is heated, heat is _______________ by the system. The amount of heat added is given a _______________ sign. When a system is cooled, heat is _______________ by the system. The amount of heat is given a _______________ sign. If a gas expands, it must push the surrounding atmosphere away. Thus, work is done _______________ the system and is given a _______________ sign. If a gas is compressed, then work is done _______________ the system. This work is given a _______________ sign.
e. What is the change in internal energy if 50 J of heat are released from a system, and the system does 80 J of work on its surroundings?