CHE3161 week 2

Which of the following is a cold reservoir?

• solar panel

• ocean

• lake

• car

What decide how many percent of energy can be converted to work?

• heating efficiency

• thermal efficiency

• power efficiency

• work efficiency

• Yes

• No

Is irreversible adiabatic process an isentropic process?

• Yes

• No

• Not sure

Is this equation related to the first law of thermodynamics?

• Yes

• No

What assumption do you need to reach this equation?

• Steady state

• Mass = 1 unit

• No heat release to the surrounding

• Entropy > 0

Can a machine generate the exact work that we want if we apply the ideal amount of heat to the machine?

• Yes

• No

• Not sure

Consider a piston with a weight pressing it to compress air. How do we reduce the work loss due to friction when we remove/add the weight?

• Good morning

• No you can't avoid friction even theoretically

• Divide the weight to 2 or more

• Add weight

Can we reverse an irreversible process?

• No, impossible

• Yes, magic

• Yes, but with extra energy consumption

• 

How could we integrate entropy into 1st law energy balance?

• 
• Look for the terms that appear in both entropy and 1st law energy balance equation

• No you can't do that, entropy belongs to second law and it is used separately to support the first law

•