8. Thermal Physics Flashcards
(24 cards)
What is the internal energy of a body?
The sum of the randomly distributed kinetic and potential energies of all of its particles.
What happens as the temperature of a gas increases?
- Average particle speed increases.
- The average kinetic energy of each particle increases.
- The distribution curve becomes more spread out.
What direction does heat energy transfer in?
Hot to cold.
What is the definition of specific heat capacity.
The amount of energy that is needed to raise the temperature of 1kg of a substance by 1˚C or K.
What is the formula for specific heat capacity?
Q = mc∆θ
What is a continuous-flow calorimeter?
A tube where the temperature of the flow is measured at the input and the output, and heat is supplied in between to raise the temperature of the water.
What happens when a substance changes state (what is constant and what isn’t)?
The kinetic energy and temperature are constant but the internal energy changes.
What is the definition for specfic latent heat of vaporisation or fusion?
The quantity of thermal energy needed to be gained or lost to change the state of a substance.
What is the formula for the specific latent heat of vaporisation or fusion?
Q = ml
What is Boyle’s law?
At a constant temperature the pressure and volume of a gas are inversely proportional.
How is Boyle’s law expressed as constant?
pV = constant
What is an ideal gas?
- A gas that obeys Boyle’s law at all temperatures and Charles’ law.
What is Charles’ law?
At a constant pressure, the volume is directly proportional to its absolute temperature T.
How is Charle’s law expressed as a constant?
V / T = constant
What is the pressure law?
At a constant volume, the pressure of an ideal gas is directly proportional to its absolute temperature T.
How is the pressure law expressed as a constant?
p / T = constant
What is (relative) molecular mass?
The sum of the relative atomic masses of all of the constituent atoms.
What is the Avogadro constant?
The number of atoms in exactly 12g of the carbon isotope (atomic mass = 12, proton number = 6).
6.02x10^23 mol^-1
How many atoms/molecules are in 1 mol of a substance (assuming that it is a substance of only that atom or molecule)?
6.02x10^23
What is the ideal gas equation for n moles?
pV = nRT
Where R = 8.31, the molar gas constant.
What is the ideal gas equation for N molecules?
pV = NkT
Where k is the Boltzmann constant.
What is the formula for work done when a gas expands (at a constant pressure)?
Work done = p∆V
What is the equation for the pressure on the wall of a cube in the x direction?
Pressure, p = Nm(mean square speed) / V
Where N is the amount of molecules, m is the mass of each molecule,
