Physics Test #2 Flashcards
Gas
Non-interacting atoms that fill a volume and exert pressure
Avogadro’s Number
size of gas samples by measuring in moles
Macroscopic Qualities
collection of molecules
Microscopic Qualities
individual molecules within collection
Kinetic Theory
The macroscopic qualities of a gas are a result of the average microscopic qualities of a very large number of molecules
Heat of Transformation
when a sample undergoes a phase change
Heat of Vaporization
liquid to gas
Heat of Fusion
solid to liquid
Phase Change
a substance changes from one form to another
Solid
molecules tightly pack, strong bonds, sustains a regular shape
Liquid
molecules are loosely packed compared to a solid, weak interaction, molecules move faster than a solid, takes the shape of container
Gas
molecules are free to move, little to no interaction with each other, moves at higher speeds, volume expands or contracts to fill container
Phase Equillibrium
when two or more phases coexist and are stable
Phase Diagram
plots the behavior of the material as a function of pressure and temperature
Thermodynamics
the relationship between heat flow, energy, and work in a given system
1st Law of Thermodynamics
-the total energy of an isolated system is constant
-any change in a system’s internal energy is related to the heat transferred to the system and the work done by the system
Compression
heat must leave the system
Expansion
heat must be absorbed by system
Isothermal
pressure and volume can change; Q flows in/out
Adiabatic
fully insulated, no heat flow
Specific Heat
measures how temperature changes with heat flow
Heat Engine
converts heat into work
Spontaneous
hot to cold
2nd Law of Thermodynamics
when two objects are brought into thermal
contact, the spontaneous heat flow is always
from hot to cold
Entropy
measure of the amount of disorder in a given system (increases when heat is added)
3rd Law of Thermodynamics
no temperature can be lower than absolute zero, no object can ever attain a temperature of absolute zero
Calorie
amount of heat needed to raise 1g of water 1° C
Conduction
transfer of heat through a substance
Convection
as a fluid heats, it becomes less dense, it rises, and colder fluid is now heated
Radiation
EM waves carry energy as heat (thermal radiation)
Ideal Gas
molecules don’t interact with each other
Vapor Pressure
pressure that exists above surface of fluid
Engine Concept
can’t be 100% efficient because there would be no flow of heat
Why does sweating cool you off?
loss of water from your body (via evaporation) decreases body temp.
Sublimation
liquid to vapor
Mac and Cheese Boiling on Mountain
boiling point decreases as pressure decreases…therefore water boils at lower temperatures in higher elevations…this lower temperature means the food will need to cook for longer
Zeroth Law of Thermodynamics
Two bodies are in equilibrium when their temperatures are equal and unchanging
“n”
number of moles
“N”
number of molecules
