Thermal physics Flashcards
Define “heat”.
Thermal energy that is transferred due to a temperature difference. (Joules)
When should you use “Kelvin” temperature?
Any question involving temperature (or change in temperature) can be solved using Kelvin scale.
When should you use “Celsius” temperature?
Many of our reference temperatures (freezing, boiling, body temp) are known as °C references. You should only use Celsius in an equation if you are asked for “change in temperature”. (deltaT)
State the temperature of absolute zero.
0 K (-273.15 °C)
Outline the significance of absolute zero.
This is the temperature where the average kinetic energy of particles reaches zero. All atomic motion ceases.
Define internal energy.
The sum of the kinetic and potential energy of all particles of a sample.
Define temperature.
A measure of the average random kinetic energy of the particles of a substance.
E = 3/2 k T k = Boltzman constant (T = Kelvin temperature)
What is special about ideal gases?
Their internal energy is entirely kinetic.
(There are no intermolecular forces: The have no potential energy.)
What are the assumptions of the ideal gas model?
Particles are far apart compared to their size.
There are no intermolecular forces.
Collisions are completely elastic.
(Particles are indistinguishable, small, hard spheres.)
When should you use Fahrenheit temperature?
Never.
What is conduction?
The transfer of heat by a substance to another substance by touching.
ΔQ / Δt = kA ΔT / Δx
Formula used when T is constant
PV1 = PV2
What is convection?
The flow of heat through a fluid or gas caused by temperature changes.
Formula used when V is constant
P/T1 = P/T2
Formula used when P is constant
V/T1 = V/T2
