Practice #2

Question 1

What are the liquefied petroleum gases?

a) butane and air
b) propane and air
c) propane and butane
d) methane and butane

Answer 1

c) propane and butane

Question 2

What is the purpose of adding mercaptan to fuel gases?

a) improve gas flow in piping
b) reduce harmful emissions when burned
c) improve ability to ignite when burning
d) to make it readily detectable in the atmosphere

Answer 2

d) to make it readily detectable

Question 3

Approximately how much gas is present in air?

Answer 3

20%

Question 4

What is the definition of limits of flammability?

a) % of gas by volume of air
b) % of CO2 by volume of air
c) % of gas by volume of oxygen

Answer 4

% of gas by volume of air

Question 5

What are the lower and upper explosive limits of CH4?

a) 1.9% - 8.5%
b) 2.0% - 10%
c) 2.4%-9.5%
d) 4% - 14%

Answer 5

4-14%

Question 6

How much does propane increase in volume when changing from liquid to a gas?

a) 270 times
b) 360 times
c) 520 times
d) 600 times

Answer 6

a) 270 times

Question 7

How much energy is in 17m3 of CH4?

a) 17,000 btu
b) 600 270 btu
c) 856 350 btu
d) 1 500 675 btu

Answer 7

b) 35.315 x 17 x 1000 = 600 270 btu

Question 8

How much energy is in 50 ft3 of CH4 that is under pressure of 10psig?

a) 50 MBH
b) 67 MBH
c) 76 MBH
d) 84 MBH

Answer 8

84 MBH

vtp formula

Question 9

1.5 ft3 cylinder of nitrogen is under pressure of 2200 psig. if all contents release, what is vol?

a) 215 ft3
b) 219 ft3
c) 223 ft3
d) 226 ft3

Answer 9

d) 226ft3

Question 10

An appliance is rated for 455,000 btu/hr. the equivalent stated in kw is

a) 110
b) 133
c) 1597
d) 5970

Answer 10

133

Question 11

A combustible mixture of CH4 has an ignition temp of?

a) 1000
b) 1300
c) 920
d) 3600

Answer 11

b) 1300F

Question 12

The specific gravity of propane gas is?

a) .6
b) 1.0
c) 1.5
d) 2.0

Answer 12

1.5

Question 13

Upper limits of flammability of propane gas is?

a) 4%
b) 6.5%
c) 9.5%
d) 14%

Answer 13

c) 9.5%

Question 14

At atmospheric pressure, propane will start to vaporize from a liquid to a gas at a temp of ?

a) 32F
b) -32F
c) -44F
d) -258F

Answer 14

c) -44F

Question 15

the specific gravity of liquid propane is?

a) .5
b) 1.0
c) 1.5
d) 2.0

Answer 15

.5

Question 16

Chemical formula for propane is?

a) c2h4
b) c4h10
c) c3h8
d) c4h8

Answer 16

c3h8

Question 17

max theoretical flame temp of a mixture of natural gas and air is?

a) 1200f
b) 1350f
c) 3600f
d) 3900f

Answer 17

3600f

Question 18

Which of the following fuel gases has the greatest specific gravity and will thus require the greatest effort to push gas through piping?

a) propane gas
b) natural gas
c) butane gas
d) propane/air mix

Answer 18

butane gas

Question 19

One m3 of natural gas will produce approx ______ btu energy when completely burned

Answer 19

35.31 x 1000 = 35310

Question 20

Calorific value of c3h8 is

a) 2500 btu/ft3
b) .7323kw/ft3
c) 25.87 kw/m3
d) all of the above

Answer 20

d) all of the above

Question 21

Natural gas can be changed to a liquid at

a) 32f
b) 0f
c) -44f
d) -258f

Answer 21

-258f

Question 22

An appliance rated for 375,000 btu/hr. Metric equivalent in kw is approx

a) 110
b) 357
c) 1200
d) 1963

Answer 22

110

Question 23

The expansion ratio of propane liquid to gas is

a) 1:100
b) 1:230
c) 1:270
d) 1:360

Answer 23

1:270

Question 24

For every 1000 btu of heat produced by combustion of natural gas, the products of combustion should include

a) 1 cubic foot of h20
b) 1 cubic foot of co2
c) 2 cubic foot of co2
d) 1 cubic foot of co

Answer 24

1 cubic foot of co2

Question 25

For a forced air furnace with a draft hood firing at an input of 100,000btuh, calculate total air requirements

a) 100 cubic feet per hour
b) 1000 cubic feet per hour
b) 1500 cubic feet per hour
d) 3000 cubic feet per hour

Answer 25

3000 cubic feet per hour

10+5+15=30 x 1000 = 3000

Question 26

The proper combustion of natural gas should include

a) co2 + h20 + co + n2 + heat
b) co2 + h20 + n2 + heat

Answer 26

b)

Question 27

For every 1000 btu of heat produced by a fuel gas, how many cubic feet of combustion air is required to complete the combustion process?

a) 5
b) 10
c) 15
d) 30

Answer 27

b) 10