1.2 Kinetic particle theory of matter Flashcards
Chapter: States of matter (20 cards)
According to kinetic theory, what happens when a substance is heated?
Particles absorb thermal energy, which is converted into kinetic energy.
This makes the particles move faster, increasing their energy and possibly changing the state of the substance.
What is kinetic particle theory?
Kinetic theory explains the behavior of matter in terms of particle movement.
It states that
1. All matter is made up of tiny particles
2. These particles are in constant motion
3. The freedom of movement and the arrangement of the particles is different for the three states of matter
4. The pressure of a gas is produces by the atoms or molecules of the gas hitting the walls of container.
What happens to particles when a solid is heated?
Particles vibrate more as they absorb heat.
As the temperature increases, vibrations become stronger until the solid structure breaks down, and the substance melts into a liquid.
What happens when a liquid is heated to its boiling point?
With more heating, the liquid expands and particles gain more kinetic energy.
Once particles have enough energy to overcome attractive forces, the liquid boils and changes to a gas at the boiling point.
What happens to the volume of a gas when temperature increases?
As temperature increases, gas particles move faster, and the volume of the gas increases (if pressure is constant).
What happens to gas density if its volume increases?
If volume increases, the density of the gas decreases, because the same amount of particles are now spread over a larger space.
What happens to gas pressure when the volume of its container is decreased?
When a gas is squeezed into a smaller volume, the particles collide more often with the container walls, so the pressure increases.
This is known as Boyle’s Law.
What happens to the kinetic energy of gas particles when temperature increases?
As temperature increases, the kinetic energy of gas particles also increases, causing them to move faster.
What effect does increased kinetic energy have on gas particles in a container?
With more kinetic energy, gas particles move faster and collide more frequently and forcefully with the container walls, leading to an increase in pressure.
What is the relationship between volume of the container and pressure in gases?
A decrease in volume causes an increase in pressure, because gas particles collide more frequently with the walls of the container.
What is a lattice?
A regular three dimensional arrangement of atoms , molecules or ions in a crystalline solid
What is an atom?
The smallest particle of an element that can take part in a chemical reaction.
What is a molecule?
A group of atoms held together by covalent bonds
Exothermic or Endothermic?
Freezing
Exothermic
Exothermic or Endothermic?
Melting
Endothermic
Exothermic or Endothermic?
Boiling
Endothermic
Exothermic or Endothermic?
Condensation
Exothermic
Why are condensation and freezing exothermic?
Condensation and freezing are exothermic because energy is released when attractive forces form between particles. These are usually intermolecular forces, like in water or ethanol.
What are exothermic changes?
A process or chemical
reaction in which heat energy is produced and
released to the surroundings.
ΔH for an exothermic change has a negative value.
What are endothermic changes?
A process or chemical
reaction that takes in heat from the surroundings.
ΔH for an endothermic change has a positive value.
