Refresher Module

Question 1

What is organic chemistry?

Answer 1

study of structure, properties, and reaction software ORGANIC COMPOUNDS (carbon containing)

Question 2

What are hydrocarbons?

Answer 2

simplest organic compound containing H + C in single bonds and no functional groups (alkanes and cycloalkanes)

Question 3

What are functional groups?`

Answer 3

group of 1+ atoms whose STRUCTURE gives it particular PROPERTIES + predictable pattern of REACTIVITY

Question 4

How can functional groups be identified?

Answer 4

π-bonds and heteroatoms

Question 5

What are the 4 types of hydrocarbon functional groups? What are their properties?

Answer 5

Alkanes: not reactive bc all C-C and C-H sigma bonds)

Alkenes: contains double bond - π-bonds are weaker than sigma = more reactive = more functional

Alkynes: contains triple bonds (2π)

Aromatics: ring structure of alternative single and double bonds

Question 6

What are heteroatoms? Why are they important for functional groups?

Answer 6

atoms besides H and C

• heteroatoms have 1+ Lone pairs so electron density around these atoms is different = effects physical properties and reactivity

Question 7

What determines the intermolecular forces that are in a molecule?

Answer 7

structure (controls physical properties) bc of e- distribution

Question 8

How does the strength of intermolecular forces compare to covalent bonds?

Answer 8

weaker than covalent bonds but are collectively strong enough to influence physical properties (melting, boiling points, solubility)

Question 9

What is ELECTROSTATICS?

Answer 9

• strongest intermolecular force = ionic structures
• attraction between two molecules of opposite formal charge

Question 10

What are DIPOLE-DIPOLE INTERACTIONS?

Answer 10

attractive force between the NEGATIVE end of a PERMANENT dipole in a molecule & the POSITIVE end of a PERMANENT dipole in another molecule

Question 11

How does electrostatics and dipole-dipole interactions compare?

Answer 11

electrostatics is strongest (formal charge compared to delta + or -)

Question 12

What is HYDROGEN BONDING? How does it’s strength compare?

Answer 12

• type of dipole-dipole interactions specific to delta + H atom as it is connected to electronegative atom (O or N)
• stronger type of dipole-dipole interaction because there is a greater difference between the electronegativities

Question 13

What are hydrogen bonds donors and acceptors?

Answer 13

donor: hydrogen
acceptor: other atom H is attracted to

Question 14

What are Dispersion (London) forces?

Answer 14

• exist in all molecules close to each other
• temporary dipoles created by electron repulsion
• weakest

Question 15

How does the molecule size impact melting and boiling point?

Answer 15

longer chain = higher surface area = more intermolecular forces = more difficult to break bonds = higher melting and boiling points

Question 16

How does the molecule branching impact melting and boiling point?

Answer 16

more branching = lower surface area = less dispersion force availability = easier to break bonds = lower melting and boiling points

Question 17

How does ring structure impact melting and boiling point?

Answer 17

ring structure = packs well together = increase SA = increase intermolecular forces = more difficult to break bonds = higher melting and boiling points

Question 18

How does the types of bonds generally impact melting and boiling points?

Answer 18

highest mp + bp: electrostatic force

h-bonding

dipole-dipole (permanent dipole)

lowest: London forces

Question 19

What is solubility?

Answer 19

how well a solute (molecule) dissolves in a particular solvent

Question 20

What is the relationship between the solute and solvent?

Answer 20

molecules are most soluble when the types of intermolecular forces are well matched between solute and solvent

Question 21

What are the 3 main solvents?

Answer 21

1. polar protic solvents
2. polar aprotic
3. non-polar

Question 22

Wha are POLAR PROTIC solvents?

Answer 22

can act as H-bond donors and miscible in water

Question 23

Wha are POLAR APROTIC solvents?

Answer 23

strong dipoles

many can act as H-bond acceptors

often highly soluble in water

Question 24

Wha are NON-POLAR solvents?

Answer 24

generally held together by dispersion forces

not miscible in water

Question 25

What are the properties/uses of water as a solvent?

Answer 25

• highly polar
• lab purification
• adding more non-polar groups decreases water solubility and vice versa

Question 26

hydrophilic?
hydrophobic?

Answer 26

hydrophilic: ‘water loving’
- polar enough from favourable intermolecular forces

hydrophobic: “water fearing”
- only London forces
- not string enough to form/overcome intermolecular forces in water

Question 27

How does branching impact solubility?

Answer 27

water h-bonds branched molecules better than unbranched (less dispersion forces) = increase solubility

Question 28

How does charge impact solubility?

Answer 28

charged molecules interact with water by electrostatics = high reactivity = high solubility

Question 29

formal charge calculations?

Answer 29

valence electrons - # bonds on that atom - # unshared e-