U1: Thermal Physics

Question 1

How does spacing of atoms differ from gases to solids and liquids

Answer 1

One particle of gas will occupy 1000x more area than one of liquid or solid

Question 2

Equation for Density of molecules

Answer 2

P =

m of 1molc • #molc in cubic meter

Question 3

Equation for #molc in a box:

Answer 3

(1/x)^3 = tot #molc

Where x is molecular spacing

Question 4

Equation for S.H.C

Answer 4

E = m • C • /\T

Question 5

Equation for latent heat energy

Answer 5

E = mL

Where L is latent heat of molecule

Question 6

What is specific latent heat of

a) fusion?
b) vaporisation?

Answer 6

Specific latent heat is Energy per unit mass of a substance required to change the substance at a constant temperature to a different state.

a) solid to liquid
b) liquid to gas

Question 7

Definition of S.H.C

Answer 7

Amount of thermal energy required to raise the temperature of a unit mass of substance by a unit temperature rise

Question 8

Equation linking pressure and speed of a molecule

Answer 8

P = ⅓ • D • v^2

Where D is density and v can replaced by the mean squared speed of all molecules

Question 9

State the ideal gas equation

Answer 9

( P1 • V1 ) / T1 = ( P2 • V2 ) / T2

Question 10

Equation containing the molar gas constant

Answer 10

( P • V ) / T = nR

n = number of moles
R = gas constant

Question 11

Equation containing Boltzmann constant

Answer 11

( P • V ) / T = NK

N = #molc
K = Boltzmann k, 1/gas constant (R of one mole)

Question 12

Kinetic energy of a gas molecule

Answer 12

E = 3/2 • k • T

Where k is the Boltzmann constant

Question 13

What is Avogadro’s constant?

Answer 13

Number of particles in one mole = 6.02x10^23

Question 14

Given temperature remains constant what is the relationship between pressure and volume of a gas

Answer 14

P = 1/V

Question 15

State Boyle’s law

Answer 15

The volume of a fixed mass of gas is inversely proportional to the pressure exerted on it, provided temperature remains constant