Chapter 1: Intro to thermodynamics

Question 1

Where does the energy go when our body looses internal energy?

Answer 1

Heat transfer, doing work, stored fat, cell repair/growth (small fraction)

Question 2

what is a system?

Answer 2

A quantity of matter or a region in space chosen for study

Question 3

what are surroundings?

Answer 3

The mass or region outside the system (we do our measuring in the surroundings)

Question 4

What are boundaries?

Answer 4

Real or imaginary surface that separates the system from its surroundings.
It can be fixed or movable.

Question 5

what is a closed system?

Answer 5

Matter can not go in and out of the system, but energy and volume can.

Question 6

what is an open system?

Answer 6

Volume stays constant, but both mass and energy can cross the boundary.
ex: blood of human heart

Question 7

what is an isolated system?

Answer 7

No mass, heat or work may cross the boundaries. It is a closed system with no energy crossing.

Question 8

what are intensive properties?

Answer 8

Independent of mass of system, such as temperature, pressure and density

Question 9

what are extensive properties?

Answer 9

Values that depend on size or extent, such as total mass & total volume

Question 10

what are specific properties?

Answer 10

Extensive properties (depend on size) per unit mass

Question 11

what is a state?

Answer 11

Condition of a system defined by properties.
At a given state, all properties of a system have fixed values, if one value changes, the state changes

Question 12

what is the state postulate?

Answer 12

state of a simple compressible system is completely specified by 2 independent, intensive properties

Question 13

what is a simple compressible system?

Answer 13

if a system involves no electrical, magnetic, gravitational, motion and surface tension effects

Question 14

what is a single-phase system?

Answer 14

temperature and pressure are independent

Question 15

what is a multi-phase system?

Answer 15

temperature and pressure are dependant

Question 16

what is thermal equilibrium?

Answer 16

temperature is the same throughout the entire system

Question 17

what is mechanical equilibrium?

Answer 17

no change in pressure at any point of the system with time

Question 18

what is phase equilibrium?

Answer 18

the system involves 2 phases and when the mass of each phase reaches an equilibrium level and stays there, hence no exchange of mass between the 2 phases

Question 19

what is a process?

Answer 19

change from state 1 to state 2

Question 20

what is a path?

Answer 20

series of states through which a system passes during a process

Question 21

what is a cycle?

Answer 21

process during which the initial and final states are identical

Question 22

what is the quasistatic or quasi-equilibrium process?

Answer 22

• process that remains infinitely close to equilibrium state at all times.
• It is sufficiently slow process that allows system to adjust itself internally so properties in one part of system do not change any faster than those other parts.
• each and every second can be considered quasi-stable.

Question 23

when do work-producing devices deliver the most amount of work?

Answer 23

when they operate on a quasi-equilibrium process.
Ex: boiling water in microwave

Question 24

what is isothermal process?

Answer 24

temperature constant

Question 25

what is isobaric process?

Answer 25

pressure constant
If temperature increases slowly, cylinder will expand to keep pressure constant

Question 26

what is isochoric (isometric) process?

Answer 26

volume constant

Question 27

what is a diathermic (diabetic) system?

Answer 27

energy is allowed in and out in the form of heat, system is in thermal contact with surroundings

Question 28

what is adiabatic system?

Answer 28

no heat is allowed in or out, such as an insulated system
closed system

Question 29

what is endothermic process?

Answer 29

process that absorbs heat

Question 30

what is exothermic process?

Answer 30

process that releases heat

Question 31

what happens to an endothermic process in a diathermic container?

Answer 31

decreases temperature of surroundings

Question 32

what happens to exothermic process in diathermic container?

Answer 32

increases temperature of surroundings

Question 33

what is a steady process?

Answer 33

does not change with time

Question 34

what is a uniform process?

Answer 34

no change with location

Question 35

what is the steady-flow process?

Answer 35

through a control volume, the mass and energy contents remain constant (steady process) but fluid properties may change with position (but not with time).

Question 36

what are examples of steady-flow processes?

Answer 36

turbines, pumps, boilers, condensers, heat exchangers, power plants, refrigeration systems

Question 37

what is absolute pressure?

Answer 37

actual pressure at a given position. It is measured relative to absolute vacuum (i.e. absolute zero pressure)

Question 38

what is vacuum pressure?

Answer 38

pressure below atmospheric pressure

Question 39

what is gauge (relative) pressure?

Answer 39

measured relative to local atmospheric pressure

Question 40

what is atmospheric/barometric pressure

Answer 40

air pressure in atmosphere (what you measure) at a given point

Question 41

Hydrostatic pressure

Answer 41

pressure exerted by a fluid at equilibrium at my point in time due to force of gravity
pressure is the same at all points in horizontal place regardless of geometry (changes in vertical plane)

Question 42

what is the pressure inside of cylinder equal too?

Answer 42

sum of all pressures applied on it
hence combination of atmospheric pressure, pressure due to weight of piston and pressure applied by spring.

Question 43

what is absolute temperature?

Answer 43

pressure of matter is zero, absolute zero kelvin, hence particles in substance are motionless