Solids, Liquids and Gases

Question 1

What is the density of a material?

Answer 1

-mass per unit of volume

Question 2

Equation for density hen you know the mass and volume

Answer 2

Mass/density x volume

Question 3

What is pressure?

Answer 3

Amount of force applied per unit of area

Question 4

State an equation linking pressure, force and area

Answer 4

force /pressure x area

Question 5

Unit of pressure and how else can it be expressed?

Answer 5

Pascals

1Pa= 1 Newton / meter²

Question 6

In solids, pressure acts in the direction of force. In which direction does pressure act in liquids or gases?

Answer 6

It acts in all directions equally

Question 7

State and equation linking pressure difference, depth, density of liquid and gravitational field strength

Answer 7

pressure (Pa) =depth (m) x density (kg/m³) x g (m/s²)
p=h x p x g

Question 8

How do you convert between degree celsius and kelvin?

Answer 8

Cº → +273→ Kelvin

Question 9

Explain why Kelvin scale is used in science instead of celsius

Answer 9

Kelvin scale is directly proportional to the average kinetic energy of the particles. At 0K particles do not move but at 0ºC particles still move.

Question 10

Explain the pressure of a gas in terms of the motion of particles

Answer 10

The particles move in random directions. WHen they collide with the walls of a container they exert a force which acts at a right angle to the container. This causes pressure.

Question 11

How does changing the temperature of a gas affect the velocity of the particles?

Answer 11

The higher the temperature, the more kinetic energy the particles have and therefore the faster the average velocity of the particles

Question 12

How does the temperature affect the pressure of a gas?

Answer 12

Increasing temperature, increases the average kinetic energy of particles so they move faster,
Therefore particles collide harder and more frequently. This increases the pressure

Question 13

State an equation linking initial pressure, final pressure, initial temperature and final temperature

Answer 13

P1/T1=P2/T2

Question 14

Explain how changing the volume of a gas affects the pressure of the gas

Answer 14

Volume and pressure are inversely proportional assuming temperature and mass of the gas is kept constant. Therefore as the volume decreases (gas in compressed) pressure increases; as a volume increases (gas is expanded) pressure decreases

Question 15

State an equation linking initial pressure initial volume, final pressure and final volume for a gas

Answer 15

P1 X V1 = P2 X V2

Question 16

State 2 assumptions you should make while using this equation

Answer 16

-Fixed mass
-Fixed temperature

Question 17

In a bicycle pump, how does pressing the piston lead to an increase in the temperature inside the piston?

Answer 17

-Pressing the piston leads to a decrease in volume
-This leads to an increase in pressure
-The particles collide more frequently
-The velocity of the particles increases
-Therefore their temperature will increase

Question 18

What is meant by a state of matter?

Answer 18

A form in which matter can exist, based on the particle arrangement in a substance

Question 19

Order the states on matter starting with the one where the particles have the least kinetic energy

Answer 19

Solid→Liquid→Gas

Question 20

Use kinetic energy to explain the structure of liquids

Answer 20

The particles have some kinetic energy. They are free to move and can move around in random directions within the volume of the liquid

Question 21

Explain the movement of particles in a solid

Answer 21

The particles vibrate around a fixed position as they do not have enough kinetic energy to move freely

Question 22

Explain the structure of particles in gases

Answer 22

Almost no forces between them and therefore they are completely free to move and move at high speeds in random directions

Question 23

Which state is the densest and why?

Answer 23

Solids, because the particles are tightly packed together in a uniform structure

Question 24

Does a gas have a high or low density and why?

Answer 24

A low density, because there is no attraction between the particles meaning that they are very spread out. This means there are less particles per unit volume.

Question 25

Why is a liquid described to have a moderate density but still similar to that of a solid?

Answer 25

The particles are still tightly packed together but they can slide over eachother

Question 26

Name physical changes that can occur which don’t change the mass of a substance

Answer 26

-Melting
-Freezing
-Boiling
-Evaporating
-Condensing

Question 27

Why does heating increase the temperature of a substance?

Answer 27

Temp of a substance depends on the average kinetic energy of the particles. When you jeat the substance, you put in thermal energy therefore kinetic energy of the particles increases therefore they move faster and temp increases.

Question 28

How does heating cause a substance to change state?

Answer 28

At specific temps, when you heat the substance thermal energy supplied is used to break the bonds of attraction between particles causing a state change. During state change temperature does not change since average KE does not increase

Question 29

What is specific heat capacity?

Answer 29

The energy require to raise one kilogram of a material by one degree celsius

Question 30

Equation to calculate the energy required to change the temperature of a substance?

Answer 30

Q = m x c x ΔT