First Law of Thermodynamics

Question 1

What is the equation for work (w)?

Answer 1

w = -Pext delta V (J)

Question 2

At constant volume and free expansion what is work?

Answer 2

Work is 0

Question 3

Conversion of 1 L*atm to Joules

Answer 3

101.325 J

Question 4

What is the equation for work at isothermal, reversible and adiabatic condition?

Answer 4

w = - nRT ln Vf / Vi

Question 5

Conversion of 1 calorie to Joules

Answer 5

4.184 J

Question 6

Equation for Specific heat

Answer 6

q = mc delta T (J/gK)

Question 7

Equation for Heat capacity

Answer 7

q = C delta T (wherein C = mc) (J/K)

Question 8

For an adiabatic system what is Heat (q) and Internal Energy (U)?

Answer 8

q = 0

delta U = work

Question 9

At constant volume and no additional work what is Internal Energy (U)?

Answer 9

delta U = qv

Question 10

What is the equation for Enthalpy (H)?

Answer 10

delta H = delta U + delta (PV)

Question 11

At constant pressure what is the equation for Enthalpy (H)?

Answer 11

delta H = qp = Cp delta T ( Cp is the heat capacity at constant pressure)

Question 12

For an ideal gas what is the equation for Enthalpy?

Answer 12

delta H = delta U + delta ngas (RT)

Question 13

What is the relationship of Cp and Cv?

Answer 13

Cp - Cv = nR

Question 14

For an adiabatic expansion of gas what is the equation for work?

Answer 14

w = Cv delta T
ViTi^c = VfTf^c ( c = Cv,m / R) (Monoatomic, Cv,m = 3/2R)
PfVf^gamma = PiVi^gamma (gamma = Cp,m / Cv,m)

Question 15

What is Internal Energy (U) and Enthalpy (H) under isothermal condition when it is an ideal gas?

Answer 15

delta U & delta H = 0