Chapter 1 Theromodynamics Introduction And Prelinmaries

Question 1

What is thermodynamics system?

Answer 1

Device or combination of devices containing matter that is under study

Question 2

What is control volume ?

Answer 2

Containing matter and device inside a control surface

Question 3

What is control surface ?

Answer 3

Boundary of the control volume. It could physical or imaginary. It could be moveable or static. It may be open to mass flow and may have flow of energy ( heat or work ).

Question 4

What is control mass?

Answer 4

Control mass is where mass is constant all the time and the system is closed.

Question 5

Difference between closed system and open system ?

Answer 5

Closed system ( fixed mass) and open system ( involving flow of mass)

Question 6

What is phase ?

Answer 6

Phase is quantity of matter that is homogeneous throughout. When more than one phase is present they are separated by phase boundary. In each phase substance may exist at various temperature or pressure, thermodynamics term would be various states.

Question 7

What is state ?

Answer 7

State refers to specific conditions or configurations of a system as defined by certain properties such as temperature, pressure, volume and entropy.

Question 8

What is condensation ? Sublimation? Deposition?

Answer 8

Condensation gas to liquid

Sublimation solid to gas ( without passing through liquid phases)

Deposition gas to solid

Question 9

What is intensive property ? Examples ?

Answer 9

Intensive property is independent of mass for example temperature, density, specific volume , pressure.

Question 10

What is extensive property ? Examples ?

Answer 10

Extensive property is dependent on mass basically depends on the size of material. For example volume, mass and heat capacities

Question 11

What is process and cycle ?

Answer 11

Whenever one or more property of the system changes, we say that change in state has occurred. The path of succession of states through which system passes is called the process.

Whenever a system in given initial state goes through a number of different process and finally returns to original state that is called a cycle.

Question 12

What is specific volume of substance ?

Answer 12

It’s inverse of density and its volume per unit mass

Question 13

What is gauge pressure ?

Answer 13

Difference between the absolute pressure and atmospheric pressure.

Question 14

When two points are on the same height but separated by some distance d do they have same pressure ?(t/f)

Answer 14

True

Question 15

What does barometer measure ? Why

Answer 15

Atmospheric pressure due to the near vacuum at top of the closed tube above the vertical column fluid.

Question 16

What is zeroth law of thermodynamics?

Answer 16

When two bodies have equal temperature with a third body, they have equal temperature with each other.

The law is basis of temperature measurement. Every time a body has equality of temperature with thermometer, we can say that body has the temperature we read on thermometer.

Question 17

What is absolute temperature scale with respect to Celsius and Fahrenheit ?

Answer 17

Celsius is kelvin and Fahrenheit is rankie

Question 18

What are Celsius and Fahrenheit based on ?

Answer 18

Both are based on ice point and steam point. Ice point is defined as the temperature of a mixture of ice and water that is in equilibrium with saturated air at pressure of 1 atm. For boiling in which water and steam are in equilibrium at 1 atm.