The first law

Question 1

What is diathermal?

Answer 1

Where you get perfect heat transmission through a wall

Question 2

What is adiabatic

Answer 2

Where you get no heat transmission through a wall

Question 3

What are extensive variables?

Answer 3

Variables for which it changes with a change in the size if the system

Question 4

What are intensive variables?

Answer 4

Variables for which it does not change with a change in the size if the system

Question 5

What are examples of extensive variables?

Answer 5

Volume
Mass
Entropy

Question 6

What are examples of intensive variables?

Answer 6

Pressure
Temperature

Question 7

What is the first law?

Answer 7

∆U = Q − W
Heat in/out =+/-
Work done by/on= +/-

Question 8

What is the work done for a system?

Answer 8

dW=pdV
W=∫pdV from V1 to V2

Question 9

What is the work done for an isobar?

Answer 9

Constant p so W=p(V2-V1)

Question 10

What is the work done for an isochore?

Answer 10

V= constant so W=0

Question 11

What is the work done for an isotherm?

Answer 11

T=constant
p=nRT/V
So W=nRTln(V2/V1)
Also W=Q

Question 12

Does the work done depend on the path?

Answer 12

Yes as at lower T p is lower so W is lower

Question 13

What is the work done for a closed loop?

Answer 13

∆U
So Q=W

Question 14

What is the heat capacity at constant pressure?

Answer 14

Cp=Cv+R

Question 15

What is the gamma factor for heat capacity?

Answer 15

γ =Cp/Cv

Question 16

For an adiabatic process what is constant?

Answer 16

pV^γ=constant
TV^(γ-1)=constant
Q=0

Question 18

Summary of an Isotherm?

Answer 18

∆T=0
∆U=0
pV=constant
W=nRTln(V2/V1)

Question 20

Summary of an Isochore?

Answer 20

∆V=0
Q=nCv(T2-T1)
W=0

Question 21

Summary of an Isobar?

Answer 21

∆p=0
∆T=p∆V/R
dW=pdV
Q=∆U+p∆V