Phases of matter, thermal energy temperature, and heat transfer Flashcards
What is the difference between temperature, thermal energy and heat?
Thermal energy is the energy contained in a system. Heat is the flow of thermal energy. Temperature is the average kinetic energy of the molecules.
Solid
- definite shape
- definite volume
- definite mass
atoms and molecules are in a fixed position and in a pattern and pact together
Liquid
- indefinite shape
- definite mass
- definite volume
atoms and molecules are moving around and bouncing off of eachother and pact together
Gas
- definite mass
- indefinite shape
- indefinite volume
atoms and molecules are bouncing off of eachother and have a big amount of space between eachother
6 phase changes
- melting - solid to liquid
- freezing - liquid to solid
- boiling / evaporation - liquid to gas
- condensation - gas to liquid
- sublimation - solid to gas
- deposition - gas to solid
3 ways thermal energy is transferred
- Conduction is the transfer of energy from one molecule to another by direct contact.
- Convection is the movement of heat by a fluid such as water or air.
- Radiation is the transfer of heat by electromagnetic waves.
How does heat flow?
from high temperature to low temperature
Temperature difference
the greater difference, the faster heat transfer occurs
latent heat
the heat required to convert a solid into a liquid or vapor, or a liquid into a vapor, without change of temperature.
thermal equilibrium
The condition under which two substances in physical contact with each other exchange no heat energy. They are at the same temperature.
Specific heat capacity
the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree).
Relationships in gas
- pressure and temp - directly proportional
- temp and vol - inversely proportional
- pressure and vol - directly proportional
Why do materials contract when cooled and expand when heated?
When heat increases, speed increases, in the atoms causing atoms to expand.
Four main parts to the kinetic molecular theory
1) All matter is made of tiny particles
2) The particles are in constant motion
3) The amount of motion is proportional to temperature
4) Energy cannot be created or destroyed but can be changed from one form to another
What is the freezing point?
32 °F/0 °C
