Thermodynamics

Can I have any energy transfer as heat transfer that is 100% available?

Graph below show the entropy versus energy U of two system 1 and 2 at constant volume. The initial energies of the systems are indicated by U₁, i and U₂, i,

Electrical appliances (TV, stereo) use electric power as input. What happens to the power? Are those heat engines? What does the second law say about those devices?

Find the internal energy of 1 kg of superheated steam at a pressure of 10 bar and 280ºC. If this steam is expanded to a pressure of 1.6 bar and 0.8 dry, determine the change in internal energy. Assume specific heat of superheated steam as 2.1 kJ/kg-K.

A room is heated with an electric space heater on a winter day. Examine the following control volumes, regarding heat transfer and work , including sign. 

(a) The space heater. 

 (b) Room 

(c) The space heater and the room together 

State the scope of thermodynamics in thermal engineering.

A drag force on an object moving through a medium (like a car through air or a submarine through water) is F_d = 0.225 A ρV². Verify the unit becomes Newton.  

Define thermodynamics. Justify that it is the science to compute energy, energy and entropy.

Which of the following reactions has the largest value of ∆S◦ ?

1. K(s) + O₂(g) → KO₂(s) 

2. BaCl₂· 2 H₂O(s) → BaCl₂(s) + 2 H₂O(g)

3. N₂(g) + 3 H₂(g) → 2 NH₃(g)

4. NH₃(g) + HCl(g) → NH₄Cl(s)

5. 2 H₂(l) + O₂(l) → 2 H₂O(g) 

Is energy transfer as work 100% available?