3.6.2 Thermal Physics

Question 1

absolute scale

Answer 1

temperature scale in Kelvin

Question 2

absolute zero

Answer 2

0K / 273.16 degrees celcius lowest possible temperature

Question 3

triple point of water

Answer 3

273.16K where water, ice and water vapour exist in thermal equilibrium

Question 4

boiling point

Answer 4

temperature at which pure liquid boils at atmospheric pressure

Question 5

Boyle’s Law

Answer 5

for a fixed mass of gas at constant temperature P x V is constant

Question 6

Boltzmann constant k

Answer 6

molar gas constant divided by the Avogadro number

Question 7

Brownian motion

Answer 7

random and unpredictable motion of a particle caused by the collisions with the molecules surrounding it at random

Question 8

Charles’ Law

Answer 8

for fixed mass of an ideal gas at constant pressure the V = kT

Question 9

coolant

Answer 9

fluid used to prevent machine or device from becoming dangerously hot - pumped through core of nuclear reactor to transfer thermal energy from core to heat exchanger

Question 10

specific heat capacity

Answer 10

energy needed to raise the temperature of 1kg of a substance by 1K without a change of state

Question 11

heat exchanger

Answer 11

steel vessel containing pipes through which hot coolant in a sealed circuit is pumped, causing water thats passing through the steel vessel in separate pipes to turn to steam which is used to drive turbines

Question 12

ideal gas

Answer 12

gas under conditions that obey Boyle’s Law

Question 13

internal energy

Answer 13

sum of the random distribution of the kinetic and potential energies of its molecules

Question 14

heat

Answer 14

energy transfer due to difference in temperature

Question 15

specific latent heat of fusion

Answer 15

energy needed per unit mass to change the state of a solid to liquid without a change of temperature

Question 16

specific latent heat of vaporisation

Answer 16

energy needed per unit mass to change the state of a liquid to a gas without a change of temperature

Question 17

mean kinetic energy

Answer 17

for a molecule of gas at absolute temperature T it has mean kinetic energy = 3/2kT

Question 18

melting point

Answer 18

temperature at which a pure substance melts

Question 19

mole

Answer 19

amount of substance consisting of Na particles of the substance

Question 20

molarity

Answer 20

number of moles in a certain quantity of a substance

Question 21

molar mass

Answer 21

mass of one mole of a substance

Question 22

kinetic theory of a gas assumptions

Answer 22

consist of point molecules, do not attract one another, collisions are elastic, continual random motion, time for each collision is short compared to time for which they move in container, large number of molecules

Question 23

root mean square speed

Answer 23

square root of the mean value of the squared speeds of the molecules of a gas

Question 24

thermal energy

Answer 24

internal energy of an object due to its temperature

Question 25

thermal equilibrium

Answer 25

when no overall heat transfer occurs between 2 objects at the same temperature

Question 26

temperature

Answer 26

degree of hotness of an object

Question 27

atomic mass unit

Answer 27

u - unified atomic mass constant ie 1 / 12th of the mass of an atom of the Carbon-12 isotope

Question 28

Avogadro constant Na

Answer 28

number of atoms in 12g of Carbon-12