Thermal Physics Flashcards
Temperature
“Measure of the average random Ek of the molecules in the object” (scalar)
Internal Energy
“The sum of total Ek + total Ep of molecules within a substance”
Boiling
- Takes place throughout a liquid
- Always occurs at same temp (for specific liquid)
Evaporating
- Takes place at the surface of a liquid
“A greater surface area will have a greater rate of evaporation” - Can happen at all temps (liquid will cool down if it evaporates)
Thermal Capacity (C)
Q = C∆T
The amount of energy required to raise the temperature of an object by 1K ( JK-1 OR J °C-1)
Specific Heat Capacity (c)
Q = mc∆T
The amount of energy required to raise the temperature of the unit mass of a substance by 1K ( Jkg-1 K-1) (change of temperature)
Specific Latent Heat (L)
Q = mL
The amount of energy per unit mass of a substance absorbed or released during a change of phase with a change in temp (Jkg-1) (change in phase)
p = F/A
p = pressure (Nm-2 or Pa)
F = force (N)
A = area (m^2)
Ideal Gases
pV = nRT
“An ideal gas is one that follows the three gas laws for all values of p (Nm-2 or Pa), V (m^3) and T(K). This means an ideal gas cannot be liquefied”
- undergo perfectly elastic collisions between themselves and the walls of their container
- have no intermolecular forces between them
W = p x ∆V
W = work (J)
p = pressure (Nm-2 or Pa)
V = volume (m^3)
Ēk = 3/2 x R/Na x T
Ēk ∝ T
R/Na = Kb = 1.38 x 10^-23 JK^-1
Avogadro Constant
the number of atoms in 12g of carbon-12
Boyle’s Law
at a constant temperature, the pressure of a gas
is inversely proportional to its volume
Charles’ Law
at a constant pressure the volume of a gas is proportional to its temperature (in K)
isothermal
constant temperature
