Basic Chemistry

Question 1

What’s the difference between an element and a compound?

Answer 1

An element is a single type of atom; a compound is two or more elements bonded together.

Question 2

What’s the most common element in the atmosphere?

Answer 2

Nitrogen (78%).

Question 3

What element is essential for combustion?

Answer 3

Oxygen.

Question 4

What’s the chemical formula for water?

Answer 4

H₂O.

Question 5

What does ‘diatomic’ mean in chemistry?

Answer 5

A molecule made of two atoms, like O₂ or H₂.

Question 6

What element is found in all organic compounds?

Answer 6

Carbon.

Question 7

What’s the chemical symbol for chlorine?

Answer 7

Cl.

Question 8

What’s the formula for carbon monoxide?

Answer 8

CO.

Question 9

What’s the primary health difference between CO and CO₂?

Answer 9

CO is toxic, CO₂ is an asphyxiant.

Question 10

What’s the formula for ammonia?

Answer 10

NH₃.

Question 11

What are the three main states of matter?

Answer 11

Solid, liquid, gas.

Question 12

What’s a fourth state of matter found in fires?

Answer 12

Plasma.

Question 13

What phase change occurs when a solid turns into a gas?

Answer 13

Sublimation.

Question 14

What’s the process of a gas turning into a liquid?

Answer 14

Condensation.

Question 15

What’s the boiling point of water?

Answer 15

212°F (100°C).

Question 16

What’s the freezing point of water?

Answer 16

32°F (0°C).

Question 17

What’s the main difference between evaporation and boiling?

Answer 17

Evaporation happens at any temperature; boiling requires heat above the boiling point.

Question 18

What is the term for a liquid changing to gas at temperatures below its boiling point?

Answer 18

Evaporation.

Question 19

What phase change happens in a BLEVE?

Answer 19

Rapid liquid-to-gas expansion.

Question 20

What’s an example of sublimation in hazmat?

Answer 20

Dry ice (CO₂) turning into gas.

Question 21

What are the two main types of chemical bonds?

Answer 21

Ionic and covalent.

Question 22

What happens in an exothermic reaction?

Answer 22

It releases heat.

Question 23

What’s an example of an exothermic reaction in hazmat?

Answer 23

Combustion.

Question 24

What happens in an endothermic reaction?

Answer 24

It absorbs heat.

Question 25

What’s an example of an endothermic reaction?

Answer 25

Ammonium nitrate dissolving in water.

Question 26

What happens when an acid and base mix?

Answer 26

Neutralization, producing salt and water.

Question 27

What’s an example of a violent acid-base reaction?

Answer 27

Sulfuric acid and sodium hydroxide.

Question 28

What gas is released when metals react with acids?

Answer 28

Hydrogen gas.

Question 29

What’s the danger of organic peroxides?

Answer 29

Highly unstable, can self-react explosively.

Question 30

What’s the hazard of alkali metals in water?

Answer 30

Violent reaction with fire or explosion.

Question 31

What does pH measure?

Answer 31

Acidity or alkalinity of a substance.

Question 32

What pH range is acidic?

Answer 32

0-6.

Question 33

What pH range is basic (alkaline)?

Answer 33

8-14.

Question 34

What pH is neutral?

Answer 34

7.

Question 35

What’s an example of a strong acid?

Answer 35

Hydrochloric acid (HCl).

Question 36

What’s an example of a strong base?

Answer 36

Sodium hydroxide (NaOH).

Question 37

What’s the hazard of mixing acids and bases?

Answer 37

Violent reaction with heat and gas release.

Question 38

What’s the main hazard of hydrofluoric acid?

Answer 38

Absorbs into skin and attacks bones.

Question 39

What PPE is required for handling strong acids or bases?

Answer 39

Chemical-resistant gloves and suit Level A

Question 40

What does a pH of 1 indicate?

Answer 40

Extremely acidic, highly corrosive.

Question 41

What is the flashpoint of a liquid?

Answer 41

Lowest temperature where vapors can ignite.

Question 42

What’s an example of a flammable liquid?

Answer 42

Gasoline.

Question 43

What’s an example of a combustible liquid?

Answer 43

Diesel fuel.

Question 44

What’s the lower explosive limit (LEL)?

Answer 44

Minimum vapor concentration needed to ignite.

Question 45

What’s the upper explosive limit (UEL)?

Answer 45

Maximum vapor concentration that can ignite.

Question 46

What’s the hazard of exceeding the UEL?

Answer 46

Too rich to burn but can ignite if diluted or ignite towards end of range May be large quantities displacing 02

Question 47

What’s the hazard of a hydrocarbon spill on water?

Answer 47

Vapors travel along the surface and can ignite.

Question 48

What does vapor density <1 mean?

Answer 48

It rises in air (lighter than air).

Question 49

What does vapor density >1 mean?

Answer 49

It sinks in air (heavier than air).

Question 50

What’s a common heavy vapor hazard?

Answer 50

Propane accumulating in low areas.

Question 51

What does an oxidizer do?

Answer 51

Supports combustion, doesn’t burn itself.

Question 52

What’s an example of an oxidizer?

Answer 52

Ammonium nitrate.

Question 53

What’s the hazard of mixing oxidizers with fuels?

Answer 53

Increased fire or explosion risk.

Question 54

What’s the hazard of chlorine reacting with organics?

Answer 54

Can create toxic and flammable gases.

Question 55

What’s the primary hazard of peroxides?

Answer 55

Unstable, can self-react explosively.

Question 56

What’s the risk of nitric acid with metals?

Answer 56

Produces toxic nitrogen dioxide gas.

Question 57

What’s a common shock-sensitive explosive?

Answer 57

Picric acid if dried out.

Question 58

What’s a water-reactive metal?

Answer 58

Sodium or potassium.

Question 59

What’s a key sign of an unstable reactive material?

Answer 59

Crystals forming around the cap.

Question 60

What’s the hazard of aluminum powder near an oxidizer?

Answer 60

Can cause a thermite-like reaction.

Question 61

What is the smallest unit of an element?

Answer 61

Atom

Question 62

True or False: A molecule is made up of two or more atoms bonded together.

Answer 62

True

Question 63

Fill in the blank: The chemical bond formed by the sharing of electrons is called a __________ bond.

Answer 63

Covalent

Question 64

What type of bond involves the transfer of electrons from one atom to another?

Answer 64

Ionic bond

Question 65

Which subatomic particle has a positive charge?

Answer 65

Proton

Question 66

What is the charge of a neutron?

Answer 66

Neutral

Question 67

What is the term for the number of protons in the nucleus of an atom?

Answer 67

Atomic number

Question 68

True or False: Electrons are found in the nucleus of an atom.

Answer 68

False

Question 69

Fill in the blank: The outermost shell of an atom is known as the __________ shell.

Answer 69

Valence

Question 70

What is the main difference between an element and a compound?

Answer 70

An element is a pure substance made of one type of atom, while a compound is made of two or more different types of atoms bonded together.

Question 71

What kind of bond is formed between two metal atoms?

Answer 71

Metallic bond

Question 72

Multiple Choice: Which particle determines the chemical properties of an atom? A) Neutrons B) Protons C) Electrons D) Nucleus

Answer 72

C) Electrons

Question 73

True or False: Isotopes of an element have the same number of protons but different numbers of neutrons.

Answer 73

True

Question 74

What is the formula for calculating the maximum number of electrons in a shell?

Answer 74

2n^2, where n is the shell level.

Question 75

Fill in the blank: The chemical formula for water is __________.

Answer 75

H2O

Question 76

What is the primary force that holds atoms together in a molecule?

Answer 76

Chemical bonds

Question 77

Multiple Choice: Which of the following represents a polar covalent bond? A) H2 B) HCl C) NaCl D) O2

Answer 77

B) HCl

Question 78

What is the pH range of acidic solutions?

Answer 78

0 to 7

Question 79

True or False: The atomic mass of an element is the weighted average of the masses of its isotopes.

Answer 79

True

Question 80

Fill in the blank: The substance formed when two or more elements are chemically bonded is called a __________.

Answer 80

Compound

Question 81

What is a characteristic property of ionic compounds?

Answer 81

They typically form crystalline structures and have high melting and boiling points.

Question 82

What is the role of valence electrons in chemical bonding?

Answer 82

Valence electrons are involved in the formation of bonds between atoms.

Question 83

Multiple Choice: Which element is most likely to form a cation? A) Sodium B) Chlorine C) Oxygen D) Neon

Answer 83

A) Sodium

Question 84

True or False: A double bond involves the sharing of four electrons between two atoms.

Answer 84

True

Question 85

What is the difference between a molecule and a compound?

Answer 85

A molecule can consist of two or more atoms of the same or different elements, whereas a compound specifically consists of two or more different elements.