Thermal Properties of Matter Flashcards
What is Internal Energy (U)?
The total energy of particles: Sum of KE (T) and PE (IMF)
Define Heat Capacity(C) and Specific Heat Capacity (SHC/c)
C: Amount of Thermal Energy absorbed/emitted per unit temperature change (△T)
c; Amount of Thermal Energy absorbed/emitted per unit mass per unit temperature change (△T)
List the 3 effects of water having a high SHC
- Requires a lot of energy to warm up, holding a good store of E when warm
- Loss of large amounts of energy causes small decrease in T and vice versa
- Sea temperature rises and falls very slowly (Moderating Effect)
List the 2 uses of water having a high SHC
- Circulating liquid in control heating systems
- Cooling liquid in engines
Define Latent Heat (L)
The amount of energy per unit mass of substance to change its state at a constant temperature
What happens during Melting and Freezing
Melting: Q absorbed to do work to weaken and overcome IMFA between molecules of solid
Freezing: Q released to strengthen IMFA between liquid atoms/molecules to become solid
What happens during Boiling and Condensation
Boiling: Q absorbed to liquid used to do work in separating molecules and pushing back surrounding atmosphere
Condensation: Q released from gas used to do work in reforming molecules
List the 6 differences between Boiling and Evaporation
Boiling: Evaporation:
-Occur at a fixed temp. -Occur at any temp.
-Temp. remains constant. -Temp. may change
-Occurs throughout liquid. -Only at exposed SA of liquid
-External Q source req. -External Q source not req.
-Relatively Fast. -Relatively slow
-Bubbles formed in liquid. -No bubbles formed in liquid
List the 6 factors affecting the rate of evaporation
- Temperature: Direct
- Exposed SA: Direct
- Motion of Air: Direct
- Humidity: Inverse
- External Pressure: Inverse
- Boiling Pt.: Inverse
