Thermodynamics

Question 1

What is thermodynamics?

Answer 1

The study of energy and its effect on a system

Question 2

What is a system?

Answer 2

A group of things that come together to perform a specific task

Question 3

What is internal energy?

Answer 3

The summation of the KE and the PE of a molecule. (Random Molecular Movement Energy) given by the symbol “U”.

Question 4

How is the internal energy distributed?

Answer 4

Randomly, meaning that any particle can have any amount of energy

Question 5

What is potential energy?

Answer 5

The position and interactions of molecules determine Potential Energy.
The further apart the molecules are the greater their potential energy

Question 6

What is the Celsius?

Answer 6

Determined based on the melting (0) and boiling point of water (100) in order to make a scale

Question 7

What is the Kelvin?

Answer 7

Has the same increments as the Celsius, but isn’t based on the boiling point of water, so starts at 0

Question 8

What is absolute 0?

Answer 8

When molecules have minimum internal energy. It is 0 Kelvin and -273.15 Celsius

Question 9

What is the specific heat capacity?

Answer 9

The energy required to increase the temperature of 1kg of a substance by 1K

Question 10

What is the formula for energy using specific heat capacity?

Answer 10

Energy = mass * specific heat capacity * change in temperature
ΔE = mcΔθ

Question 11

What are solids?

Answer 11

Molecules vibrate around a fixed position

Question 12

What are Liquids?

Answer 12

Molecules constantly freely move around but are still attracted to each other

Question 13

What are gases?

Answer 13

Molecules move freely and randomly

Question 14

What happens when you increase the temperature of a substance?

Answer 14

Increase kinetic energy and therefore internal energy

Question 15

What happens when there is a change of state ?

Answer 15

kinetic energy stays the same as the energy is being transferred to the potential energy store of the molecules.

Question 16

What is the specific latent heat? (fusion)(vapourisation)

Answer 16

The energy required to change the state of 1kg of a substance

Question 17

The formula relating energy to specific latent heat?

Answer 17

Energy change = specific latent heat x mass of substance changed
ΔE = L*Δm

Question 18

What Assumptions are made in Kinetic theory?

Answer 18

The motion of molecules is random
Totally elastic collisions
Molecules move in straight lines at constant speeds
Negligible intermolecular forces
The particles are all identical

Question 19

Boyle’s Law?

Answer 19

Law linking the pressure and the volume at a CONSTANT TEMPERATURE.
As the volume decreases, pressure increases as there is an increased collision rate

P = k/V so PV = k

Question 20

Charles’ Law?

Answer 20

Law linking the temperature and the volume at a CONSTANT PRESSURE.
V = KT As the temperature increases there should be more collisions. But pressure is kept constant so volume must increase instead

Question 21

Pressure Law?

Answer 21

Law linking the temperature and the pressure at a CONSTANT VOLUME.
P = kT
As temperature increases, average kinetic energy increases, more collisions so more pressure

Question 22

Ideal Gas equation?

Answer 22

PV = nRT “R” is the gas constant “n” Avagadro’s constant

PV = NkT “N” for number of molecules “k” for Boltzmann constant

PV = 1/3 Nmc^2

Question 23

What is the value of the Boltzmann constant?

Answer 23

k = 1.38 x10-23

Question 24

Gas constant?

Answer 24

R = 8.31

Question 25

Equation linking energy RMS velocity, mass, and temperature?

Answer 25

mc²/2 = 3kT/2