Chapter 1.2 Particle Theory

Question 1

What is Brownian Motion

Answer 1

It is the continual motion of particles within a liquid or gas

Question 2

What is a smoke cell

Answer 2

It is a glass box filled with smoke and air
Observation - the smoke particles in there were moving randomly/irregularly/haphazardly
Conclusion - the observed irregular motion of the smoke particles was due to the bombardment (collision) of the moving air particles.

Question 3

What are tiny particles?

Answer 3

Tiny particles are atoms. This had been derived from the Greek word Atomos, meaning “unsplittable”. Groups of atoms combine to form a molecule.
Atoms and molecules are the basic building blocks of all matter

Question 4

How big are molecules

Answer 4

They are very small and cannot be seen with our bare eyes

Question 5

Basic Assumptions/Main Ideas of the Particle Theory

Answer 5

1. Matter is made up of tiny particles called atoms, and groups of atoms join together to form molecules.
2. Particles are always moving.
3. Particles attract each other.

Question 6

Different States of Matter
Solids

Answer 6

They are arranged in a regular pattern (rows and columns). They hardly have any intermolecular distance. The molecules cannot move but they can vibrate in their fixed position. They have high density.
In a solid the particles are very close to each other and held in a position by a very strong cohesive force of attraction.

Question 7

Liquids

Answer 7

In a liquid the particles are slightly apart, not as packed as solid molecules. And the cohesive force of attraction is not as strong, it cannot hold them anymore (it is slightly weaker) which is why liquid particles and can slide past each other and take the shape of its container.

Question 8

Gases

Answer 8

The molecules are randomly arranged and they are separated by a very large intermolecular distance. The cohesive force of attraction is almost negligible. The gas molecules are in a constant state of rapid, random motion.

Question 9

Why are gases highly compressible

Answer 9

Gases are highly compressible because of their large intermolecular distance.

When gases are compressed the intermolecular distance is reduced, because the molecules come closer together and the gas tales up less space

Question 10

Differences between Three States of Matter

Answer 10

(in table format)
Solids -
1. Solids are arranged in regular rows and columns
2. The molecules are packed together very closely, there is hardly any intermolecular distance.
3. The molecules do not move. They vibrate in a fixed position.
4. Solid molecules have a strong cohesive force of attraction.

Liquids -
1. Liquids are arranged in an irregular pattern
2. Liquids are spaced slightly further apart
3. They can change places and move.
4. They have a slightly weaker cohesive force of attraction

Gases -
1. Gas molecules are arranged randomly.
2. The molecules are further apart. They have large intermolecular distance.
3. They move in a very high speed in all directions
4. Gases have an almost negligible cohesive force of attraction.