Deck 17: Chemistry and Combustion

Question 1

What is the smallest particle of a compound that can exist in a free state and take part in a chemical reaction known as?

A) element
B) atom
C) proton
D) molecule

Answer 1

molecule

Question 2

How many electrons does a hydrogen atom have?

A) one
B) two
C) eight
D) one hundred and two

Answer 2

one

Question 3

How many hydrogen atoms are there in a single molecule of water?

A) one
B) two
C) four
D) eight

Answer 3

two

Question 4

Which of the following is an example of diatomic oxygen?

A) ozone
B) a single atom of oxygen
C) ambient oxygen at ground level
D) oxygen combined with 2 atoms of hydrogen

Question 5

Which of the following is not a fluid?

A) steam
B) water
C) gaseous propane
D) ice

Question 6

Where is the positive charge located in an atom?

A) in the valence
B) entirely in the nucleus
C) distributed evenly in the shells
D) distributed evenly between the nucleus and the shells

Question 7

What is present in the greatest quantity (by mass) in a diesel engine cylinder at the moment of ignition?

A) fuel
B) hydrogen
C) nitrogen
D) oxygen

Question 8

When diesel fuel is combusted in an engine cylinder, which of the following is produced in the greatest quantity by mass (weight)?

A) carbon dioxide
B) water vapor
C) hydrocarbons
D) particulate matter

Question 9

Which of the following would be a typical stoichiometric ratio of a diesel fuel by mass when combusted using ambient air?

A) 1:1
B) 8:1
C) 15:1
D) 12,000:1

Question 10

Which of the following would be closest to the stoichiometric ratio of a diesel fuel by volume when combusted using ambient air?

A) 1:1
B) 8:1
C) 15:1
D) 12,000:1

Question 11

In a diesel engine, the time period between the start of injection and the beginning of combustion is known as:

A) injection lag
B) ignition delay
C) pre-combustion
D) afterburn

Question 12

What type of condition is diesel knock caused by?

A) bottom end bearing failure
B) afterburn
C) detonation
D) backfire

Question 13

Ideally, when should the highest cylinder pressure occur during combustion in a diesel engine?

A) ignition
B) injection
C) beginning the third phase of combustion
D) afterburn

Question 14

What should you know about carbon monoxide that could adversely affect your health?

A) it is explosive
B) breathing it can be lethal
C) it has a low boiling point
D) contact with exposed skin can be harmful

Question 15

What state is fuel-sourced particulate matter (PM) in as it exits the tailpipe?

A) solid
B) liquid
C) gaseous
D) plasma

Question 16

Technician A says that sulfur dioxide emissions from diesel engines are much less of a problem today than they were back in 2006. Technician B says that diesel-sourced particulate matter (PM) smaller than the eye can see is capable of causing respiratory problems in humans. Who is correct?

A) Technician A only
B) Technician B only
C) Both A and B
D) Neither A nor B

Question 17

For what reason is carbon monoxide (CO) much less of an emissions problem in diesel engines than in gasoline-fueled engines?

A) gasoline contains much more carbon
B) diesel fuel contains much more hydrogen
C) diesels run twice as hot as gasoline engines
D) CO results when fuel/air mixtures are close to, or richer than stoichiometric

Question 18

At what zone location within the cylinder will (initial) ignition take place in properly functioning diesel engine?

A) at the tip of the injector
B) in the piston headland
C) where the fuel/air mixture is at its most lean
D) where the fuel/air mixture is close to stoichiometric