4Th Class Power Engineering Chapter 19

Front 1

When heat is supplied or taken away and causes an immediate change in temperature without changing the state, the heat is known as?

Back 1

Sensible heat

Front 2

When heat is supplied or taken away and causes a change in state without temperature change, then the heat is known as?

Back 2

Latent heat

Front 3

The ________ is the heat required to change a unit mass of solid to a unit mass of liquid at the same temperature.

Back 3

Latent heat of fusion

Front 4

The _________ is the heat required to change a unit mass of liquid to a unit mass of vapor or gas at the same temperature and pressure.

Back 4

Latent heat of evaporation

Front 5

The temperature at which the change from water to steam takes place is called the boiling point or?

Back 5

Saturation temperature

Front 6

Steam produced with sensible heat is called?

Back 6

Saturated steam

Front 7

If steam doesn't contain any particles of water in suspension, it is called?

Back 7

Dry saturated steam

Front 8

_______ is just at the temperature of the change of state from liquid to vapor.

Back 8

Saturated steam

Front 9

Superheated steam

Back 9

Superheated steam

Front 10

What is the latent heat of evaporation for water?

Back 10

2257 kJ/kg

Front 11

What is the latent heat of fusion of water?

Back 11

335 kJ/kg

Front 12

Boiler efficiency =

Back 12

Mass of steam produced × (enthalpy of the steam - enthalpy of the feedwater) / mass of fuel burned × heating value of fuel

Front 13

What is the wet steam equation?

Back 13

H = hf + qhfg

Front 14

The heat required to change a unit mass of liquid to a unit mass of vapor or gas is known as?

Back 14

Latent heat of evaporization

Front 15

Saturation temperature is the temperature at which water changes to steam. It is also called?

Back 15

The boiling point

Front 16

Find the quantity of heat required to produce 79% dry steam at 8 000 kPa from feedwater at 50°C.

A) 2 245.93 kJ/kg

B) 2 758 kJ/kg

C) 1 969.49 kJ/kg

D) 1 841.73 kJ/kg

E) 2 539 kJ/kg

Back 16

A) 2 245.93 kJ/kg

Front 17

How much heat must be supplied to 200 kg of water at 20°C to make steam at 850 kPa that is 87% dry?

A) 2 039.4 kJ

B) 407 880 kJ

C) 1 774.28 kJ

D) 484 507.6 kJ

E) 424 627.98 kJ

Back 17

D) 484 507.6 kJ

Front 18

The total enthalpy of 11 kg of steam at 950 kPa is 24 528.713 kJ. Determine the dryness of the steam. A) 0.68

B) 0.54

C) 0.73

D) 0.87

E) 0.64

Back 18

C) 0.73

Front 19

Saturated steam:

A) Is steam that is neither wet nor dry

B) Is steam at saturation temperature

C) Required for all superheaters

D) Is steam saturated with moisture E) Contains more than 50% moisture

Back 19

B) Is steam at saturation temperature

Front 20

Find the volume of 2.3 kg of dry saturated steam at 11 000 kPa.

A) 3.70 m³

B) 0.037 m³

C) 370 m³

D) 37.0 m3

E) 0.37 m³

Back 20

B) 0.037 m³

Front 21

In Column 9 of Table 1 of the Steam Tables, the enthalpy (hfg) found in that column is known as the:

A) Sensible heat of fusion

B) Latent heat of fusion

C) Sensible heat of evaporation

D) Sensible heat of enthalpy

E) Latent heat of evaporation

Back 21

E) Latent heat of evaporation

Front 22

The total enthalpy of 18 kg of steam at 9 000 kPa is 42 409.224 kJ. Determine the dryness fraction of the steam.

A) 0.75

B) 0.90

C) 0.72

D) 0.85

E) 0.88

Back 22

C) 0.72

Front 23

You need to convert volume of steam from g/cm3

Back 23

You need to convert volume of steam from g/cm3

Cm3 to kg3 move decimal point 3 to the left