Kinetic molecular theory Flashcards
what is the kinetic molecular theory
that the particles that make up a substance have a certain amount of kinetic energy (movement energy), meaning that they are all moving, and the way in which they move is responsible for the physical state of matter.
what is diffusion
the movement of particles from a high concentration to a low concentration. Diffusion takes place in both liquids and gases.
what determines the motion of particles
The motion of the particles depends on the amount of energy that the particles have as well as the attractive forces between the particles. Energy can be added to the particles in the form of heat.
what four rules form from the Kinetic molecular Theory
- All matter is made up of particles (atoms, molecules or ions).
- Their particles are in constant motion.
- Due to their motion, the particles have kinetic energy.
- There are forces of attraction and repulsion between the particles.
what are the phases of matter
all matter is found in one of three phases and most matter can change from one phase to another by the addition or removal of heat energy.
the three phases are:
solids
liquids
gases
how do particles interact in a solid
In a solid, the particles are packed tightly together and have little kinetic energy. The particles have strong intermolecular forces and they don’t have enough energy to overcome the forces between them, so the particles vibrate in place. This explains why solids have a fixed shape and volume. The particles vibrate (slight motion) but stay in their crystal structure.
how do particles interact in a liquid
In a liquid, the particles have more kinetic energy than in a solid. The particles have enough energy to overcome the forces between them, so they can move around freely amongst one another. The particles tend to move wherever they can reach inside the container which is why the liquid takes the shape of the container. The spaces between the particles are bigger in a liquid than in a solid. This means that the forces between the particles are weaker than in a solid; although it is important to note that there are still forces between the particles, they are just not as strong as they are in a solid. Sometimes particles on the surface of a liquid have enough energy to overcome the intermolecular forces of the particles below and can escape from the liquid phase.
how do particles interact in a gas
In a gas the particles have even more kinetic energy than in a liquid. The particles have more than enough kinetic energy to overcome the forces between them so they move wherever they can reach. This also means that the spaces between the particles are much bigger than in a liquid, making the forces between the particles smaller. In a closed container the particles of a gas will have so much energy that they collide with the walls of the container. This is why a balloon will expand when you add more air, because the air particles collide with the sides of the balloon pushing outwards and expanding the balloon.
