the particulate nature of matter

Question 1

what are the 3 characteristics of solids

Answer 1

1. Strong forces of attraction between particles, particles are packed very closely together in a fixed and regular pattern
2. Atoms vibrate in position but can’t change position or move
3. Solids have a fixed volume, shape and high density

Question 2

what are the 3 charcateristics of liquids

Answer 2

1. Weaker attractive forces in liquids than in solids, particles are close together in an irregular, unfixed
2. Particles can move and slide past each other which is why liquids adopt the shape of the container they’re in and also why they are able to flow
3. Liquids have a fixed volume but not a fixed shape and have a moderate to high density

Question 3

what are the 4 characteristics of gases

Answer 3

1. No intermolecular forces
2. Particles are far apart
3. No fixed volume,
4. Gases have low density

Question 4

what is melting

Answer 4

Melting is when a solid changes into a liquid

Question 5

how does the melting occur

Answer 5

Requires heat energy which transforms into kinetic energy, allowing the particles to move

Question 6

what is boiling

Answer 6

Boiling is the rapid vaporization of a liquid

Question 7

how does boiling occur

Answer 7

Requires heat which causes bubbles of gas to form below the surface of a liquid, allowing for liquid particles to escape from the surface and within the liquid

Question 8

what is freezing

Answer 8

Freezing is when a liquid changes into a solid

Question 9

how do you find the freezing point of a substance

Answer 9

This is the reverse of melting and occurs at exactly the same temperature as melting, hence the melting point and freezing point of a pure substance are the same. Water for example freezes and melts at 0ºC

Question 10

what is evaporation

Answer 10

When a liquid changes into a gas

Question 11

how does evaporation occur

Answer 11

Evaporation occurs only at the surface of liquids where high energy particles can escape from the liquid’s surface

Question 12

what is the evaporation point

Answer 12

vaporation occurs over a range of temperatures

Question 13

what is condensation

Answer 13

When a gas changes into a liquid,

Question 14

how does condensation occur

Answer 14

When a gas is cooled its particles lose energy and when they bump into each other they lack the energy to bounce away again, instead they group together to form a liquid

Question 15

what is the condensation point

Answer 15

condensation to occur and it takes place over a range of temperatures

Question 16

what is sublimation

Answer 16

When a solid changes directly into a gas

Question 17

how does an increase in temperature cause an increase in pressure

Answer 17

The pressure that a gas creates inside a closed container is produced by the gaseous particles hitting the inside walls of the container. As the temperature increases, the particles in the gas move faster, impacting the container’s walls more frequently

Question 18

what is brownian motion

Answer 18

the random movement of particles in a liquid or a gas produced by large numbers of collisions with smaller, often invisible particles

Question 19

what is diffusion

Answer 19

the movement of a substance from an area of high concentration to an area of low concentration

Question 20

what is the evidence of brwonian motion

Answer 20

the pollen grains were being moved by individual water molecules. This confirmed that atoms and molecules did exist, and provided evidence for particle theory.

Question 21

which state of matte does diffusion occur faster in

Answer 21

Diffusion occurs much faster in gases than in liquids as gaseous particles move much quicker than liquid particles

Question 22

which gases diffuse faster

Answer 22

At the same temperature, different gases do not diffuse at the same rate.
This is due to the difference in their relative molecular masses
Lighter gas particles can travel faster and hence further, therefore the lower its relative mass the faster a gas will diffuse