Kinetic Model of Matter Flashcards
State the Kinetic Model of Matter
The kinetic model of matter states that matter is made of tiny particles in continuous, random motion
Define Brownian Motion.
Brownian motion refers to the random movement of tiny particles in a fluid (eg. smoke in the air or pollen in water)
Explain briefly why gases have no fixed shape and volume.
Substance in the gaseous state have no fixed shape and size because the intermolecular force between molecules is weaker.
Describe what happens when a solid undergoes melting.
When a solid melts, intermolecular forces weaken while the kinetic energy stays the same. Hence particles will move further apart, causing the change of state to occur as solid melt to form liquid.
Describe what happens when a substance undergoes heating without a change of state.
When a substance is heated without any change in state, the intermolecular forces stay the same and the molecules move at a faster speed as the average kinetic energy of molecules increases.
Explain how air molecules create pressure on the inside walls of a container
Air is composed of a large number of particles in continuous, random motion.
Each particle occasionally collides with the walls of the container, exerting
a force on the wall. Since pressure is defined as the force acting normally
per unit area, the numerous collisions with the walls give rise to the pressure
exerted on the walls.
Explain why the gas pressure increases as the temperature of the air increases.
When temperature increases, the average kinetic energy of the air molecules increases. As a result, the molecules move faster and hit the walls more frequently and with greater force. Since pressure is the force per unit area, the pressure of the air in the box increases.
