The third Law of thermodynamics/entropy principle

what is the third law of thermodynamics?

the entropy of a pure crystalline substance at absolute zero temperature is zero

what is absolute entropy?

entropy relative to the entropy of a pure crystalline substance at absolute zero (which is zero)

what is the order of entropy of the three main states of matter?

Gas > Liquid > Solid

what is the increase of entropy principle?

entropy is always increasing

why is entropy generated during irreversible processes?

due to the presence of irreversibilties

how can you identify the reversibility of a system based off of entropy generated?

Entropy generated < 0 IMPOSSIBLE

Entropy generated = 0 REVERSIBLE

Entropy generated > 0 IRREVERSIBLE

what is the equation of entropy for an isothermal case?

δQ/T

what is the basic energy direction convention?

Q in +

Q out -

W in -

W out +

What is the sign convention for a carnot heat engine and for the environment?

when is entropy conserved?

entropy is only conserved during IDEALISED REVERSIBLE PROCESSES and increases during all actual processes

how can you work out quality from steam tables using entropy?

S = S(f) + xS(fg)

what is an isentropic process?

entropy change = 0