Concepts
What is a system?
A part of the universe chosen for study.
Which system exchanges both matter and energy with its surroundings?
Open system.
Internal energy is the sum of what two forms of energy?
Kinetic and potential energy.
What does temperature measure?
The average kinetic energy of particles.
Why do odors spread faster in hot air?
Because particles move faster at higher temperatures.
According to particle theory, everything is made of what?
Particles.
Which system exchanges energy but not matter?
Closed system.
What happens to internal energy when particle kinetic energy increases?
It increases.
Which has higher average kinetic energy: hot water or cold water?
Hot water.
Give one everyday example of heat causing particles to move faster.
Perfume smell spreads faster in a warm room.
What are the two main forms of energy possessed by particles?
Kinetic and potential energy.
Which system exchanges neither matter nor energy?
Isolated system.
Name one factor that affects the internal energy of a system.
Temperature (or mass, state, type of substance).
If temperature increases, what happens to particle motion?
Particles move faster.
Why does heating a substance increase its internal energy?
Because the particles gain kinetic energy.
Is internal energy stored in the object as a whole or in its particles?
In its particles.
A sealed bottle of water is an example of which type of system?
Closed system.
Can internal energy increase if only potential energy increases?
Yes.
Does temperature measure total energy or average kinetic energy?
Average kinetic energy.
Explain why ice melts when heat is added.
Particles gain energy, increasing internal energy until the solid changes to liquid.
True or False: Every particle has both kinetic and potential energy.
True.
Give one real-life example of an isolated system.
An ideal thermos flask (approximately).
Explain the relationship between temperature and internal energy.
As temperature increases, particle kinetic energy increases, so internal energy generally increases.
Can two objects have the same temperature but different internal energies? Explain.
Yes, because internal energy also depends on the amount and type of substance.
A cup of tea cools down on a table. What happens to its internal energy and why?
It decreases because heat is transferred to the surroundings.