Thermodynamics

For a given reaction, if ∆H°  rxn is (negative/positive/either) and ∆S° rxn is (negative/positive/either), then the value of ∆G° rxn will always decrease as you raise the temperature.

1. either, positive

2. positive, either 

3. either, negative 

4. negative, either 

5. positive, negative 

6. negative, positive

If I have 1 L ammonia at room pressure and temperature (100 kPa, 20°C) how much mass is that?  

State thermodynamic definition of work. Also differentiate between heat and work.

A car engine takes atmospheric air in at 70 F, no fuel, and exhausts the air at 0 F producing work in the process. What do the first and the second laws say about that?  

At a speed of 50km/h, the resistance to motion of a car is 900N. Neglecting losses, calculate the power of the engine of the car at this speed. Also determine the heat equivalent of work done per minute by the engine.

Does the statement of Clausius require a constant T for the heat transfer as in a Carnot cycle? 

Define N.T.P. AND S.T.P.

A manometer shows a vacuum of 260 mm Hg. What will be the value of this pressure in N/m² in the form of absolute pressure and what will be absolute pressure (N/m²), if the gauge pressure is 260 mm of Hg. Explain the difference between these two pressures.

The gas used in a gas engine trial was tested. The pressure of gas supply is 10cm of water column. Find absolute pressure of the gas if the barometric pressure is 760mm of Hg.

For which of the following processes does the entropy of the universe decrease? 

1. None of these is 

2. melting one mole of ice to water at 0◦C 

3. freezing one mole of water to ice at 0◦C 

4. freezing one mole of water to ice at 0◦C and then cooling it to −10◦C 

5. freezing one mole of water to ice at −10◦C