Thermodynamics L1 Core 2

Front 1

What is w?

Back 1

Work (= force x distance = transfer of energy through organized motion)

w = -pex∆V (work for expansion of a gas)

δw = -pdV

Front 2

What is U?

Back 2

internal energy (= potential + kinetic)

Front 3

Zeroth law?

Back 3

If A is in thermal equilibrium with B and B is in thermal equilibrium with C then A is in thermal equilibrium with C.

Front 4

1st law?

Back 4

∆U = q + w for a closed system

Front 5

State functions?

Back 5

U,

Path independant

Front 6

non-state functions?

Back 6

Path dependant i.e. p, V, T etc

Front 7

how can d(uv) be manipulated into an easier form?

Back 7

knowing dudv to be negligible

d(uv) = udv + vdu

Front 8

how can dh(x, y) be manipulated?

Back 8

dh(x,y) = (∂h/∂x)y dx + (∂h/∂y)x dy

Front 9

Heat capacity at constant volume?

Back 9

Cv = (∂U/∂T)V

Front 10

dq?

Back 10

dq = CvdT (heat capacity x change in T)

Front 11

Define adiabatic?

Back 11

No heat exchange with surroundings

Front 12

How can Cv and ∆U be obtained?

Back 12

adiabatic bomb calorimeters

Front 13

Enthalpy?

Back 13

H(p, T) = U + pV

(we can choose between p, T and V because there in an equation of state linking them but we can only vary two independently)

Front 14

Why is H often more useful than U?

Back 14

at constant pressure Vdp = 0 ∴ since w = -pdV

dH(p, T) = dqp

Front 15

Heat capacity at constant pressure?

Back 15

Cp = (∂H/∂T)p

gives us dH = CpdT = dqp

Front 16

How are ∆H and Cp obtained?

Back 16

isobaric calorimeters

Front 17

Define isobaric?

Back 17

process where pressure is constant

Front 18

How are the two heat capacities related in a perfect gas?

Back 18

Cp - Cv = nR