Particle Nature of Matter

Question 1

In terms of particles. What are solids like.

Answer 1

Strong forces of attraction between particles. Particles are packed together in a fixed pattern. Atoms vibrate but can’t move. Solids have fixed volume, shape and high density.

Question 2

In terms of particles. What are liquids like

Answer 2

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

Question 3

In terms of particles. What are gas’s like

Answer 3

Particles are in random movement, move quickly in all directions and collide against each other. No fixed volume, since there is a lot of space between the particles. Gases have a low density

Question 4

From solid to liquid do the intermolecular forces become weaker or do they just decrease in number without the force changing

Answer 4

The intermolecular forces don’t weaken but become less allowing liquid to move more freely

Question 5

In terms of particles. What are gases

Answer 5

Particles in gases are far apart and move fast colliding with each other. No fixed volume since there is a lot of space between particles. Gases can be compressed in low volume. Gases have low density

Question 6

What is melting

Answer 6

Melting is when a solid changes into a liquid

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

Question 7

What is boiling

Answer 7

Boiling is when a liquid changes into a gas
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
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 9

What is evaporation

Answer 9

When a liquid changes into a gas. 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
The larger the surface area and the warmer the liquid/surface, the more quickly a liquid can evaporat
No heat is required and evaporation occurs over a range of temperatures

Question 10

Condensation

Answer 10

When a gas changes into a liquid, usually on cooling. When a gas is cooled its particles lose energy and when they bump into each other, they lack energy to bounce away again, instead grouping together to form a liquid

Question 11

What sublimation

Answer 11

When a solid changes directly into a gas
This happens to only a few solids such as iodine or solid carbon dioxide. E.g carbon to carbon dioxide
The reverse reaction also happens and is also called sublimation (sometimes called deposition or desublimation)

Question 12

What does a reversible arrow mean

Answer 12

Reversible reaction

Question 13

What does an increase in temperature do to particles

Answer 13

It makes the particles move faster therefore creating more kinetic energy.
Thermal energy —> kinetic energy

Question 14

How come the pressure of inside a gas container is way more than and opened container

Answer 14

Particles are bouncing way more and colliding way more creating more kinetic energy and pressure

Question 15

An increase in temperature does what to pressure

Answer 15

An increase in temperature gives particles more energy resulting in an increase in kinetic energy making particles collide against each other more and move faster therefore increasing temperature.
Increase in temperature —> increase in pressure

Question 16

What is Brownian motion

Answer 16

is defined as the random movement of particles in a liquid or a gas from different mediums produced by large numbers of collisions with smaller, often invisible particles.

Question 17

In Brownian motion what is the movement of large particles like

Answer 17

jerky and erratic movement caused by many collisions with smaller particles

Question 18

What is diffusion

Answer 18

is the process by which different gases or different liquids mix and is due to the random motion of their particles
Diffusing particles move from an area of high concentration to an area of low concentration.

Question 19

When diffusion happens what happens with concentration of the liquids

Answer 19

Eventually the concentration of particles even out as they spread out to occupy all of the available space.

Question 20

Does diffusion require energy

Answer 20

Diffusion happens on its own and no energy input is required although it occurs faster at higher temperatures

Question 21

When diffusion evens out what is reached

Answer 21

Equilibrium is reached as everything is now equal and will be equal if one side has more then the other side will diffuse back and become equal again.

Question 22

What happens when a substance is heated

Answer 22

the particles absorb thermal energy which is converted into kinetic energy. This is the basis of the kinetic theory of matter.

Question 23

What happens when you heat a solid

Answer 23

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 24

What happens when a solid has weak intermolecular bonds

Answer 24

It means that the solid is just very soft like for example ice cream or molten there both solids but are sold and their intermolecular bonds are weak.

Question 25

What happens when liquid is heated

Answer 25

He liquid expands more and some particles at the surface gain sufficient energy to overcome the intermolecular forces and evaporate

Question 26

What graph is used to show the changes in heating solids, liquid and gases

Answer 26

The heating curve is used

Question 27

What graph is used when cooling down a substance

Answer 27

The cooling curve is used

Question 28

What’s interconversion

Answer 28

The conversion of two things into each other

Question 29

When changing state from solid to liquid or liquid to gas what is happening with the temperature.

Answer 29

While changing state, the temperature of the substance remains the same as the heat energy is rapidly converted into kinetic energy. This is called latent heat and corresponds to the horizontal sections of a heating / cooling curve.

Question 30

What is Brownian motion. 2

Answer 30

larger and visible particles are caused to move by the random bombardment of smaller, invisible particles

Question 31

Why is diffusion way faster in gases then in liquids

Answer 31

gaseous particles move much quicker than liquid particles

Question 32

Do all gases diffuse at the same temperature

Answer 32

At the same temperature, different gases do not diffuse at the same rate. This is due to the difference in their relative molecular masses. As lighter gases can travel faster hence diffusion occurs faster when lighter