Module 7

Question 1

What is an alkane?

Answer 1

A hydrocarbon with single bonds between all of the carbon atoms

Question 2

What is an alkene?

Answer 2

A hydrocarbon with at least one carbon-carbon double bond

Question 3

What is an alkyne?

Answer 3

A hydrocarbon with at least one carbon-carbon triple bond

Question 4

What is a hydrocarbon?

Answer 4

A molecule containing only hydrogen and carbon atoms

Question 5

What is an organic substance?

Answer 5

Substances in which one or more carbon atoms are covalently bonded to hydrogen atoms

Question 6

What is the molecular formula of a compound?

Answer 6

The number of atoms of each element present in a molecule

E.g. propanol (C₃H₈O)

Question 7

What is the empirical formula of a compound?

Answer 7

The simplest ratio of each atom in a compound

E.g. butane:
- The molecular formula is C₄H₁₀
- The empirical formula is C₂H₅

Question 8

What is the structural formula of a compound?

Answer 8

A visual depiction of the arrangement of atoms

E.g. propanol

Question 9

What is the condensed structural formula of a compound?

Answer 9

A visual depiction of the arrangement of atoms in a molecule without displaying the bonds present

E.g. propanol (CH₃CH₂CH₂OH)

Question 10

What is the skeletal formula of a compound?

Answer 10

A visual depiction of the bonds within a molecule without showing every atom

E.g. propanol
[PICTURE]

Question 11

What is a functional group?

Answer 11

A group of atoms attached to a carbon compound that give it characteristic properties

Question 12

Name the 8 common functional groups.

Answer 12

Alkene: carbon-carbon double bond
Alkyne: carbon-carbon triple bond
Alcohol: hydroxyl group (-OH)
Carboxylic acid: carboxyl group (-COOH)
Aldehyde: carbonyl group (C=O) at the end of a hydrocarbon chain
Ketone: carbonyl group (C=O) in the middle of a hydrocarbon chain
Amine: amino group (NH₂)
Amide: amino group and carbonyl group (-CONH₂)

Question 13

What is a haloalkane?

Answer 13

An alkane with one hydrogen atom replaced with a halogen atom

E.g. chlorobutane

Question 14

What is a homologous series?

Answer 14

A group of molecules with the same general formula and functional group that behave similarly in reactions

Question 15

What is an addition reaction?

Answer 15

A reaction that joins two or more molecules to form a larger molecule

Question 16

What are the 4 types of addition reactions?

Answer 16

• Halogenation
• Hydrogenation
• Hydration
• Hydrogen halides (hydrohalogenation)

Question 17

What is a halogenation reaction?

Answer 17

A reaction that adds a halogen molecule to:

• An alkene to form a haloalkane
• An alkyne to form a dihaloalkene or tetrahaloalkane

E.g. ethene (C₂H₄) + chlorine (Cl₂) → dichloroethane (C₂H₄Cl₂)

Question 18

What is a hydrogenation reaction?

Answer 18

A reaction that adds a hydrogen molecule to:

• An alkene to form an alkane
• An alkyne to form an alkene or alkane (requires a platinum or Lindlar catalyst)

E.g. ethene (C₂H₄) + hydrogen (H₂) → ethane (C₂H₆)

Question 19

What is a hydration reaction?

Answer 19

A reaction that adds a water molecule to:

• An alkene to form an alcohol (requires dilute sulfuric acid (H₂SO₄) as a catalyst)
• An alkyne to form a ketone or aldehyde (requires dilute sulfuric acid (H₂SO₄) and mercury II sulfate (HgSO₄) as a catalyst)

E.g. ethene (C₂H₄) + water (H₂O) → ethanol (C₂H₅OH)

Question 20

What is a hydrohalogenation reaction?

Answer 20

A reaction that adds a hydrogen halide to:

• An alkene to form a haloalkane
• An alkyne to form a haloalkene or dihaloalkane

E.g. ethene (C₂H₄) + hydrogen bromide (HBr) → bromoethane (C₂H₅Br)

Question 21

What kinds of molecules can undergo addition reactions?

Answer 21

Unsaturated molecules

Question 22

What is a fermentation reaction?

Answer 22

A reaction that chemically breaks down a substance using a living microorganism such as bacteria or yeast

Question 23

What happens to the boiling point as the carbon chain increases?

Answer 23

Boiling point increases due to a higher molar mass and increased dispersion forces

Question 24

How does branching affect boiling point and solubility?

Answer 24

Branching decreases the boiling point and solubility of molecules as it reduces the strength of dispersion forces

Question 25

What is the order of primary, secondary, and tertiary alcohols in terms of boiling point?

Answer 25

Primary alcohols > secondary alcohols > tertiary alcohols This is because the hydroxyl group becomes more crowded the more carbons it is attached to which reduces the number of potential hydrogen bonds

Question 26

When will substances dissolve?

Answer 26

If the strength of the new bonds formed are similar in strength to the pre-existing bonds between molecules

Question 27

What is the solubility of small alcohols in water?

Answer 27

Small alcohols have a high solubility in water due to their ability to form hydrogen bonds with the water molecules

Question 28

What is the solubility of large alcohols in water?

Answer 28

Large alcohols have low solubility in water as they can only form one hydrogen bond per molecule and primarily form dispersion forces which are not similar in strength to the hydrogen bonds in water molecules

Question 29

How does increasing the carbon chain affect the solubility of molecules in water?

Answer 29

Molecules become less soluble in water as the carbon chain increases due to the increasing dispersion forces which makes hydrogen bonds less dominant

Question 30

How does increasing the carbon chain affect the solubility of molecules in organic substances?

Answer 30

Molecules become more soluble in organic substances as the carbon chain increases due to the dispersion forces becoming stronger which are similar in strength to the pre-existing bonds

Question 31

What kinds of organic molecules are soluble in water?

Answer 31

Small polar organic molecules dissolve in water as the hydrogen bonds formed with water are similar to the pre-existing hydrogen bonds in the molecule

Question 32

What is the primary fermentation reaction?

Answer 32

Glucose ( + yeast as a catalyst) → ethanol + carbon dioxide C₆H₁₂O₆ ( + yeast as a catalyst) → 2C₂H₅OH + 2CO₂

Question 33

What type of environment must fermentation reactions occur in?

Answer 33

Anaerobic environments (lacking oxygen)

Question 34

What are enzymes?

Answer 34

Enzymes are agents produced by yeast that convert sugar into ethanol and carbon dioxide

Question 35

What is the optimal temperature for enzymes?

Answer 35

Between 25° and 40°

Question 36

What happens if the temperature of enzymes is too high?

Answer 36

They denature (lose their shape)

Question 37

What happens if the temperature of enzymes is too low?

Answer 37

They work too slowly

Question 38

Why must glucose be in aqueous solution in fermentation reactions?

Answer 38

Because ethanol kills yeast at concentrations higher than 15% and an aqueous solution of glucose dilutes the ethanol

Question 39

How is ethanol extracted after fermentation reactions?

Answer 39

Through fractional distillation

Question 40

What is fractional distillation?

Answer 40

Separating substances based on their differences in boiling points

Question 41

What is the process of fractional distillation for ethanol?

Answer 41

- Mixture of ethanol + water is heated over a Bunsen burner - Ethanol is evaporated and runs through a condenser - The condenser surrounds the ethanol with running water to cools it - Ethanol flows through and is collected at the end - This process is repeated a few times to purify the ethanol