Thermal Physics and Ideal Gasses -- Year 13 Flashcards
(23 cards)
What is the kinetic model of matter used to explain?
Behaviour such as changes of state and macroscopic properties
It describes how molecular behavior relates to thermal properties.
What is the internal energy of a system?
The sum of the random distribution of kinetic and potential energies associated with the atoms or molecules that make up the system
It encompasses all forms of energy within the system.
What happens to the internal energy of an object when its temperature increases?
There is an increase in its internal energy
This is due to increased kinetic energy of molecules.
Does internal energy change during a change of state?
Yes, internal energy increases but there is no change in temperature
This occurs during phase transitions like melting or boiling.
What does the first law of thermodynamics express?
Conservation of energy
It states: increase in internal energy = energy supplied by heating + work done on the system.
What is the formula for work done on a gas when its volume changes at constant pressure?
W = pAΔV
Where
p => pressure exerted by the gas
A => the are of the surface on which the pressure is acting
ΔV => the change in volume of the gas
W is positive when the gas is compressed (ΔV is negative).
How are temperatures on the thermodynamic (Kelvin) and Celsius scales related?
T(K) = (°C) + 273.15
This conversion is essential for thermodynamic calculations.
What is absolute zero in Kelvin?
0 K
It is the lowest possible temperature where molecular motion stops.
What is the formula to convert Kelvin to Celsius?
(°C) = T(K) – 273.15
This helps in converting temperature scales for practical use.
What does a thermometer utilize to measure temperature?
A physical property of a material that varies with temperature
Examples include expansion of liquids or change in electrical resistance.
What is the word equation for specific heat capacity?
Specific heat capacity = energy supplied / (mass x temperature change)
This formula helps calculate energy transfer during heating.
What is specific heat capacity?
The energy required per unit mass of the substance to raise the temperature by 1 K (or 1 °C)
It varies among different materials.
What is the formula for the energy transferred in raising the temperature of a substance?
E = mcΔθ
Where m is mass, c is specific heat capacity, and Δθ is the temperature change.
What is specific latent heat?
The energy required per kilogram of the substance to change its state without any change in temperature
It is critical during phase changes.
What is the formula for calculating energy related to specific latent heat?
E = mL
Where m is mass and L is specific latent heat.
What is the Avogadro constant (NA)?
6.02 x 10^23 mol^-1
One mole of any substance contains NA particles (atoms or molecules)
What is the equation of state for an ideal gas?
pV = nRT for n moles; pV = NRT for N molecules
p = pressure, V = volume, n = number of moles, R = gas constant, T = temperature
What are the four assumptions of the kinetic theory of gases?
- Molecules move at random, colliding elastically with the walls
- There are no forces between atoms in the gas
- The volume of the molecules is small compared to the volume of the container
- The time of each collision is small compared to the time between collisions
From the kinetic model of a gas, what relationship can be deduced?
p = Nm <c^2>
Where <c^2> is the mean-square speed of the molecules
What is the relationship between kinetic energy and thermodynamic temperature for an ideal gas?
E = (3/2)kT
E is the mean translational kinetic energy, m is mass, <c^2> is mean-square speed, k is the Boltzmann constant, and T is temperature
What is the formula for the root-mean-square speed of gas molecules?
Crms = √(<c^2>)
Where <c^2> is the mean square speed of the molecules
Fill in the blank: One mole of any substance contains ______ particles.
NA
NA = Avogadro constant
True or False: The volume of gas molecules is significant compared to the volume of the container.
False
According to the kinetic theory, the volume of the molecules is small compared to the volume of the container.
