Solids, Liquids, Gases

Question 1

Density =

Answer 1

Mass / Volume

Question 2

Pressure =

Answer 2

Force / Area

Question 3

In gases and liquids at rest where does the pressure at any point act?

Answer 3

Equally in all directions

Question 4

How do you get a lower pressure?

Answer 4

Same force applied over a larger area

Question 5

Pressure difference =

Answer 5

Height x density x gravitational field strength

Question 6

What is Pressure Difference?

Answer 6

Difference in pressure between two points in a liquid or gas

Question 7

What is Pressure?

Answer 7

Measure of force being applied to the surface of something

Question 8

What is Pressure measured in?

Answer 8

Pascals (Pa) or Kilopascal (kPa)

Question 9

What are the units of density?

Answer 9

g/cm3 or Kg/m3

Question 10

What are Solids?

Answer 10

• Strong forces of attraction
• Particles close together
• Fixed regular arrangement
• Vibrate In fixed position
• No energy

Question 11

What are Liquids?

Answer 11

• Weaker forces of attraction
• Particles close together but move past each other
• Form irregular arrangements
• Some energy
• Move in random directions at low speeds

Question 12

What are Gases?

Answer 12

• No force of attraction
• A lot of energy
• Move in random directions at high speeds

Question 13

What is Thermal energy store?

Answer 13

Energy in substances thermal energy store is held by its particles in their kinetic energy store

Question 14

What happens if you heat a liquid?

Answer 14

• Extra energy transferred into particles kinetic energy store
• Move faster
• Big bubbles of gas from in liquid = boiling

Question 15

What happens if you heat a solid?

Answer 15

• Extra energy makes particles vibrate faster

* Eventually forces between them are partly overcome and start to move around = melting

Question 16

How can particles near surface of liquid escape and become gas particles?

Answer 16

• If particles are travelling in right direction to escape
• If particles travelling fast enough - have energy in their kinetic energy stores to overcome attractive forces of the other particles

Question 17

What is Evaporation?

Answer 17

Particles escape from a liquid and become gas particles

Question 18

Describe an experiment to show that temperature remains constant during changes of state?

Answer 18

• Fill beaker with crushed ice
• Thermometer in beaker + record temperature of ice
• Hear beaker w/ Bunsen burner
• Every 20 secs record temp + state of ice - do until water boils
• Plot graph of temperature against time for experiment

Question 19

What happens if you cool a substance down?

Answer 19

You reduce the energy of particles

Question 20

What is Absolute zero?

Answer 20

• Cold as stuff can get

* Start of Kelvin scale of temperature

Question 21

How do you convert Celsius to Kelvins?

Answer 21

Add 273

Question 22

What is the Boiling point of water for Celsius and Kelvin?

Answer 22

• 100 degrees celsius

* 373 Kelvin

Question 23

What is the Particle theory?

Answer 23

• Gases are very small particles which are constantly moving in random directions
• Particles collide with / bounce off each other and the container walls
• If you Increase the temperature of gas, you give particles more energy

Question 24

What is the temperature of gas (in kelvins) proportional to?

Answer 24

The average energy in the kinetic energy stores of its particles

Question 25

What happens when gas particles collide with a container of each other?

Answer 25

* They exert a force on it * Their momentum + direction changes * In sealed container = smash against its walls, creating an outward pressure

Question 26

What happens if you heat a gas?

Answer 26

* Particles move faster and have more energy in their kinetic stores * Particles hit container walls harder + more frequently = larger force = more pressure

Question 27

What happens if you put the same fixed amount of gas in a bigger container?

Answer 27

* Fewer collisions between gas particles and container walls * Pressure decreases

Question 28

What happens if you put the same fixed amount of gas in a smaller container?

Answer 28

``` When volume reduced: •Particles more squashed up •Hit walls more frequently •Producing a larger force over a small surface area •Pressure increases ```

Question 29

What’s the equation for a fixed mass of gas at a constant temperature?

Answer 29

Constant = Pressure x Volume

Question 30

What is the equation for a gas in a sealed container at a constant volume?

Answer 30

Constant = | Pressure / Temperature(in K)

Question 31

What is a specific heat capacity of a substance?

Answer 31

The energy required to change the temperature of an object by 1 degrees per kilogram of mass

Question 32

How can you find the specific heat capacity of water?

Answer 32

* Mass of insulating container * Mass of container with water * Difference In mass is the mass of water in the container * Attach joulmeter to container + electric heater with thermometer * Measure Temp + turn on power * When temp increased, turn off power,record temp increase + energy on joulmeter * Repeat 3 times + find average