Solids, Liquids And Gases - Part 1 (T5)

Question 0

What is density measure in according to the SI system?

Answer 0

Kilograms per metre 3

Kg/m 3

Question 1

What is density measure in according to the SI system?

Answer 1

Kilograms per metre 3

Kg/m 3

Question 2

What is the SI (international system) unit for absolute temperature?

Answer 2

Kelvins

K

Question 3

Describe solids in a short paragraph..

Answer 3

Molecules in a solid material are packed as closely together as they possibly can be. They are either bonded together in predictable patterns called ‘lattices’ or jumbled up, but in each case each molecule is bonded to its neighbours by very strong chemical bonds.
The only movement that the molecules perform is vibrational movement.
Individual molecules do not move from one location to another within the material.
How vigorously they vibrate depends only on temperature, so heating up a solid will give molecules more vibrational kinetic energy.

Question 4

Describe liquids..

Answer 4

If the temperature of a solid rises to its melting point, the vibrations become so violent that some of the chemical bonds between molecules are broken and the molecules split up into groups.
This gives them freedom of movement, which is why liquids have no fixed shape.
However the molecules are still packed closely together, so liquids are also incompressible.

Question 5

Describe gases in a paragraph..

Answer 5

If the temperature of a liquid is increased until it reaches its boiling point, then all the remaining bonds between molecules are broken and each molecule exists as a separate body that does not experience any significant force of attraction to any of its neighbours.
This is why the molecules in a gas are free to spread out and fill the container they are in, no matter how big it is.
In most situations, there are huge gaps between molecules in a gas compared to the size of one molecule.

Question 6

What property do liquids share with gases?

Answer 6

They have no definite shape

Question 7

Gases have very low densities and can be compressed. Why is it difficult to compress liquids and solids?

Answer 7

Because the particles in them are almost as close together as can be

Question 8

Describe three main attributes of the particles (molecules) in a solid…

Answer 8

• tightly packed
• are held in a fixed pattern or crystal structure by strong forces between them
• vibrate around their fixed positions in the structure

Question 9

Describe three main attributes of the particles (molecules) in a liquid…

Answer 9

• tightly packed
• not held in fixed positions but are still bound together by strong forces between them
• move at random

Question 10

Describe three main attributes of the particles (molecules) in a gas…

Answer 10

• very spread out
• have no fixed positions and the forces between them are very weak
• move with a rapid, random motion