The Particulate Nature of Matter.

Question 1

Substances can be found in three states. Name them.

Answer 1

Substances can be solids, liquids or gases.

Question 2

What is all matter made of of?

Answer 2

All matter is made up of particles.

Question 3

Three types of particles make up most matter - Name them.

Answer 3

Three types of particles make up most matter - atoms, molecules and ions.

Question 4

What is an atom?

Answer 4

An atom is the smallest particle that cannot be broken down by chemical means.

Question 5

What is a molecule?

Answer 5

A molecule is a particle of two or more atoms joined together.

Question 6

What is an ion?

Answer 6

An ion is an atom or group of atoms that carries an electrical charge.

Question 7

What is the shape, volume, and density of a solid-like, and can it flow?

Answer 7

• Definite shape and volume.
• High density.
• Cannot flow.

Question 8

What is the shape, volume, and density of a liquid-like, and can it flow?

Answer 8

• Definite volume.
• Takes the shape of the container.
• Moderate to high density.
• Can flow.

Question 9

What are the shape, volume, and density of a gas-like?

Answer 9

• No definite volume.
• Spreads everywhere throughout its container.
• Low density.

Question 10

Answer the following about solids:
- Attractive forces.
- Arrangement.
- Motion.
- Proximity.

Answer 10

• Strong forces of attraction between particles.
• Fixed and regular pattern.
• Atoms vibrate in position.
• Packed closely together.

Question 11

Answer the following about liquid:
- Attractive forces.
- Arrangement.
- Motion.
- Proximity.

Answer 11

• Weaker attractive forces in liquids than in solids.
• Irregular, unfixed pattern.
• Particles can move and slide past each other.
• Particles are close together.

Question 12

Answer the following about gases:
- Attractive forces.
- Arrangement.
- Motion.
- Proximity.

Answer 12

• No attractive forces.
• Particles move everywhere rapidly.
• Particles are in random movement.
• Particles are far apart.

Question 13

State the compressibility of the following:
- Solids.
- Liquids.
- Gases.

Answer 13

• Not compressible.
• Not compressible.
• Compressible.

Question 14

What is melting?

Answer 14

Melting is when a solid changes into a liquid at a constant temperature.

Question 15

What energy does melting require and what does it transform into?

Answer 15

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

Question 16

What temperature does melting occur at?

Answer 16

Occurs at a specific temperature known as the melting point.

Question 17

What is boiling?

Answer 17

Boiling is when a liquid changes into a gas at a constant temperature.

Question 18

What does boiling require and what does it form?

Answer 18

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 19

What temperature does boiling occur at?

Answer 19

Occurs at a specific temperature known as the boiling point.

Question 20

What is freezing?

Answer 20

Freezing is when a liquid changes into a solid.

Question 21

What does freezing require?

Answer 21

Requires a significant decrease in temperature (or loss of thermal energy).

Question 22

Define evaporation.

Answer 22

When a liquid changes into a gas.

Question 23

Where does evaporation occur? Explain your answer.

Answer 23

Evaporation occurs only at the surface of liquids where high-energy particles can escape from the liquid’s surface at low temperatures, below the b.p. of the liquid.

Question 24

How can evaporation be sped up?

Answer 24

The larger the surface area and the warmer the liquid/surface, the more quickly a liquid can evaporate.

Question 25

What is sublimation?

Answer 25

When a solid changes directly into a gas.

Question 26

What is condensation?

Answer 26

When a gas changes into a liquid, usually on cooling. .

Question 27

Explain how condensation occurs.

Answer 27

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 28

What happens to energy when a substance freezes or condenses.

Answer 28

Energy is given out to the surrounding (exothermic reaction) when a substance condenses or freezes.

Question 29

What happens to energy when a substance melts or boils?

Answer 29

Energy must be put in (endothermic reaction) to melt and boil a substance.

Question 30

What happens when you heat the gas in a closed container?

Answer 30

As the temperature increases, the particles in the gas move faster, impacting the container’s walls more frequently with increased force..

Question 31

When a gas is heated in a closed container, the gas particles hit the walls of the container with increased force. Why?

Answer 31

The higher the temperature, the higher the pressure will be in the container (pressure is caused by the gaseous particles hitting the inside walls of the container).

Question 32

Evidence for the kinetic theory?

Answer 32

Brownian motion and diffusion.

Question 33

Define diffusion.

Answer 33

This is the process by which different gases or different liquids mix and is due to the random motion of their particles.

Question 34

In what direction do diffusing particles move?

Answer 34

Diffusing particles move from an area of high concentration to an area of low concentration.

Question 35

Diffusion in gases is faster than in liquids. Why is this?

Answer 35

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

Question 36

What happens with molecules with a lower molecular mass regarding the speed of diffusion?

Answer 36

Molecules that have a lower mass move faster than those with a higher mass.

Question 37

At the same temperature, different gases do not diffuse at the same rate. Why?

Answer 37

This is due to the difference in their relative molecular masses.

Question 38

What does heating a solid do?

Answer 38

Heating a solid causes its particles to vibrate more and as the temperature increases, they vibrate so much that the solid expands until the structure breaks and the solid melts.

Question 39

What does heating a liquid do?

Answer 39

Heating the liquid expands it more and some particles at the surface gain sufficient energy to overcome the attractive forces and evaporate.

Question 40

What happens when the b.p. temperature is reached for a liquid?

Answer 40

When the b.p. temperature is reached, all the particles gain enough energy to escape and the liquids boils.

Question 41

What happens when you compress gases or decrease the volume of the container?

Answer 41

When the volume of the container is decreased, the gas molecules are squashed closer together and hit the walls of the container more often.

Question 42

What happens when you heat the gas in a closed container but the volume of the gas is not fixed?

Answer 42

If the volume of the gas is not fixed, the volume of gas increases as the temperature increases.

Question 43

What is the kinetic particle theory?

Answer 43

The idea that particles are constantly in motion is called the kinetic particle theory.

Question 44

What four things do the kinetic particle theory state:

Answer 44

• Particles in gases and liquid move randomly.
• Particles in gases do not attract each other.
• Particles in gases are so tiny that their volume can be ignored.
• When the particles in gases collide they bounce off each other without any overall energy change.

Question 45

What happens if the light and heavy molecules have the same amount of energy when they collide?

Answer 45

If the light and heavy molecules have the same amount of energy when they collide, the lighter ones will bounce off the heavier ones quicker.

Question 46

What does the kinetic particles model state?

Answer 46

The kinetic particle model states that the particles in liquids and gases are in constant motion and that when the particles in gases collide they bounce off each other.

Question 47

Why is the rate of diffusion slower in liquids than in gases?

Answer 47

The rate of diffusion is slower in liquids than in gases because there are weak attractive forces between the liquid particles.

Question 48

Why does diffusion occur in gases?

Answer 48

Diffusion occurs in gases because the molecules in gases are constantly moving, colliding with each other and changing directions. Resulting in the gases spreading out.

Question 49

What does the rate of diffusion depend on?

Answer 49

The rate of diffusion depends on the relative molecular mass.

Question 50

Fill in the missing answers:
Substances with a _____ relative molecular ____ diffuse more slowly than those with a ____ relative ______ mass.

Answer 50

Substances with a higher relative molecular mass diffuse more slowly than those with a lower relative molecular mass.

Question 51

Evidence for the Brownian motion?

Answer 51

Evidence for the Brownian Motion comes from the observations of the motion of tiny visible particles suspended in liquids and gases.

Question 52

Larger heavier particles do not show Brownian Motion. Why is this?

Answer 52

This is because the differences in force of the collisions of molecules on each side of the heavier particles is not large enough to move them.

Question 53

Diagrams to revise:

Answer 53

Cooling Curve and Heating Curve, Brownian Motion.

Question 54

What is the temperature of room temperature?

Answer 54

Generally taken as about 20°C.

Question 55

What is the order of a heating curve?

Answer 55

solid heating up - solid melting - liquid heating up - liquid vaporizing - gas heating up.