5.4 Kinetic Molecular Theory And Changes In State

Question 1

Kinetic molecular theory:

Answer 1

Idea that matter is made from moving invisible particles; theory is used to explain behaviour and change in states of matter that we observe.

Question 2

KMT principles

Answer 2

1. All matter is made up of tiny particles
2. Different substances have different particles
3. That particles are in constant motion
4. The more energy the particles have, and the faster they move
5. The attraction between particles decreases with an increase in distance

Question 3

What happens when energy is added?

Answer 3

Energy added is added heat which causes particles to move faster and increased motion causes them to spread apart expanding the substance

Question 4

How does KMT explain dissolving

Answer 4

-sugar dissolving in water is sugar particles being separated from the solid parts and entering spaces between water particles
-hot water means water particles are moving faster and are capable of spreading the sugar particles at a higher rate

Question 5

How does KMT explain density

Answer 5

As substances are heated, increased motion causes particles to spread apart resulting in increase in volume, called expansion

Question 6

Why does hot air rises in cold air and cold water sinks in hot water?

Answer 6

Hot air particles move faster therefore spreading apart and gaining more volume, therefore with same mass and more volume they are less dense then cold air with less motion, more compactness and therefore more density. Hot air-less dense then rises above the cold air which is more dense