Chapter 14 Thermal Physics Flashcards
What happens if a hot object is placed next to a cold object?
The net flow of heat is from the hot object to the colder object.
What is thermal equilibrium?
This is when there is no net flow of thermal energy between them so all the objects must be at the same temperature
What is the density of ice vs water?
Ice is less dense than water. This is very uniquie
What happens to atoms/molecules in a solid?
They pack together tightly because of strong electrostatic forces. All the atoms / molecules stay together in a fixed formation
What happens to the atoms/molecules in a liquid?
They are still close together but they can move further apart and can change position
What happens to the atoms/molecules in a gas?
The atoms / molecules are free to move apart and there is almost no forces of attraction between them. They move randomely
What does the spacing of molecules in a substance at different physical phases affect?
It affects the density
What is the internal energy of a substance?
It is the sum of the randomly distributed kinetic and potential energies of atoms or molecules within a substance.
What happens to the internal energy of a substance when it is heated and why?
The internal energy increases because more heat causes the kinetic energy of a substance to increase. The hotter a substance the more kinetic energy it has
How can the internal energy of a substance increase without an increase in temperature?
If the substance is changing state. The energy is increased because the electrostatic forces between the atoms / molecules is increased
What happens when a substance is heated so it starts to melt / vaporise?
The heat energy goes into breaking the electrostatic forces and not into kinetic energy. Once the forces have been broken, only then does the heat energy go into increasing the kinetic energy
