In a single process, a system does 125 J of work on its surroundings while 75 J of heat is added to the system. What is the internal energy change for the system

Explanation:

What is the first law of thermodynamics?

"The first law of thermodynamics state that energy is conserved"

the expression bellow is the  Change in internal energy of a system

Change in internal energy of a system

= heat put into the system - work done by the system on its surroundings,

or

ΔU = ΔQ - ΔW.

given data

Work done=125J

Heat= 75J

change=?

Substituting we have

ΔU = 75- 125

ΔU = -50J

"ΔQ is positive if heat flows into the system, negative if it flows out of the system.

ΔW is positive if the system does work on its surroundings and it is negative if work is done on the system. "

a.) travels faster in solids because the particles are closer together.

air is a gas water is a liquid