Topic 1 - Solids, Liquids and Gases

Question 1

What is the triple point?

Answer 1

At one specific temperature and pressure the three phases of matter of a substance can exist in thermal equilibrium

Question 2

What is thermal equilibrium?

Answer 2

No net transfer of thermal energy between the phases

Question 3

What is temperature?

Answer 3

Temperature is a measure of the hotness of an object/A bulk measure of the internal energy of a system of molecules

Question 4

What is the relationship between temperature and internal energy?

Answer 4

Temperature is proportional to the amount of internal energy in a substance

Question 5

What is heat?

Answer 5

If the temperature of one object is higher than another object there is a net flow of thermal energy from the hotter object to the colder one, this is known as “heat”. When the object reaches thermal equilibrium they will be at the same temperature

Question 6

What is the zeroth law in of thermodynamics?

Answer 6

If 2 objects are each in thermal equilibrium with a third, then all 3 are in equilibrium with each other

Question 7

How is temperature measured?

Answer 7

In order to measure temperature a scale is needed that includes 2 fixed points at defined temperatures

Question 8

How was Celsius discovered?

Answer 8

In 1742 a Swedish astronomer Anders Celsius proposed using a scale with the 2 fixed points as the freezing and boiling point of pure water (when the atmospheric pressure is 1.01x10^5) with 100 degrees between 0 degrees and 100 degrees

Question 9

What are the problems with the Celsius?

Answer 9

The 2 fixed points vary slightly depending on the surrounding atmospheric pressure

Question 10

What is the absolute temperature scale?

Answer 10

It uses the triple point of pure water and absolute zero as its fixed points

Question 11

What SI base unit of temperature is used for the absolute scale?

Answer 11

Kelvin (K)

Question 12

What us the lowest value of Kelvin?

Answer 12

0K, here the atoms have the minimum internal energy and all classical atomic motion stops. At this point a change of 1K equals a change of 1 degrees

Question 13

What is the equation you can use to convert between Kelvin and Celsius?

Answer 13

T(K) = (Celsius) + 273

Question 14

What is the kinetic model?

Answer 14

It describes how all substances are made up of atoms or molecules, which are arranged differently depending on the phase substance

Question 15

How are solids arranged?

Answer 15

The atoms/molecules are regularly arranged and packed closely together, with strong electrostatic forces holding them in a fixed position, but they can vibrate and so have kinetic energy

Question 16

How are liquids arranged?

Answer 16

The atoms/molecules are still and very close together, but they have more Ek than solids so can change positions and flow past each other

Question 17

How are gases arranged?

Answer 17

The atoms/molecules have much more Ek than in liquids, they are much further apart. They’re free to move past each other as there are negligible electrostatic forces between them, unless they collide with each other or the container walls. They move randomly with different speeds in different directions

Question 18

Brownian motion

Answer 18

It explains the random motion of very small particles suspended in a liquid or gas. The small particles move as a result of collisions with the atoms and molecules that make up the liquid or gas

Question 19

How does a particle’s phase relate to its density?

Answer 19

Generally a substance is most dense in its solid phase and least dense in its gaseous phase

Question 20

How does water differ from different elements regarding density?

Answer 20

Water freezes into a regular crystalline pattern held together by strong electrostatic forces between the molecules. In this structure the molecules are held slightly further apart than in their random arrangement in liquid water, so ice is slightly less dense

Question 21

What is the internal energy of a substance?

Answer 21

The sum of the randomly distributed kinetic and potential energies of atoms/molecules within the substance

Question 22

What is the formulae for total kinetic energy

Answer 22

Total kinetic energy = Total PE + Total KE

Question 23

How does the internal energy of a body increase?

Answer 23

. Temperature increases the kinetic energy in the body, this makes the atoms/molecules that make up the substance move faster and increases the internal energy
. When a substance changes phase the electrostatic potential energy increases significantly

Question 24

Define SHC

Answer 24

The energy required to increase the temperature of an object with a mass of 1kg by 1K

Question 25

SHC equation

Answer 25

E=mC(change in temperature)

Question 26

Define Specific latent heat

Answer 26

The energy required to change the phase of 1kg of a substance at a constant ttemperature

Question 27

Specific latent heat of fusion

Answer 27

Solid - Liquid

Question 28

Specific latent heat of vaporisation

Answer 28

Liquid - Gas

Question 29

Specific latent heat equation

Answer 29

E=mL

Question 30

What happens to the energy of a body when the temperature increases?

Answer 30

The kinetic energy increases
The potential energy stays constant
The total energy increases

Question 31

What happens to the energy of a body during the phase?

Answer 31

The kinetic energy stays constant#
The potential energy increases
The total energy increases

Question 32

What is the amount of a substance?

Answer 32

The amount of a substance is measured in moles. One mole of a substance contains 6.02x10^23 atoms/molecules

Question 33

What is the equation linking the number of moles of a substance, Avogadro’s constant and the number of atoms/molecules in a substance?

Answer 33

N=n.Na

The number of atoms/molecules in a substance) = (number of moles of a substance).(Avogadro’s constant

Question 34

What is the equation linking the number of moles of a substance, the mass of a substance in grams and the molar mass of the substance (g/mol)?

Answer 34

n=m/V

The number of moles of a substance) = (The mass of a substance (g)).(The molar mass of the substance (g/mol)

Question 35

What is the equation for density?

Answer 35

Density = Mass/Volume