Physics

the amount of heat needed to raise the temp. of 1 kg of water by 1°C

4186

4.186

the heat required to raise or lower the temp of 1 kg of a substance by 1°C

Q=mcΔT

latent heat of fusion (L_f)

Latent heat of vaporization (L_v)

Qf > 0

Qf < 0

Qv > 0

Qv < 0

Solid C₁

Phase Change = L_f

Melting

Liquid C₂

Phase Change = L_v

Boiling

Gas C₃

140°C

110°C

• 1) Conduction
• 2) Convection
• 3) Radiation

heat transfer due to direct contact of objects that have different temps

heat transfer due to mass movement of gas or liquid molecules

heat transfered by electromagnetic radiation between objects that have different temperatures

good conductor of heat

poor conductor of heat

the 1st law is a statement of conservation of energy in terms of thermodynamic variables ΔU, Q &W

Q=ΔU+W

change in the systems internal energy

down and out

Wnet

up and in


Win

W_net/Q_h

Certain processes do not take place even though they may be consistent with the first law

- heat will not flow spontaneously from a cooler body to a warmer body

- in a thermal cycle, heat energy cannot be completely transformed into mechanical work.

- The work output is always less than the energy input.

ε = 1- (Tc/Th)

Temp must be in K

Qc/Win