Lecture 8. Fundamentals of Organic Chemistry Flashcards

1
Q

What does a skeletal formula show ?

A

The skeleton of the molecular structure

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2
Q

What is a heteroatom ?

A

Non carbon

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3
Q

What type of structure are generally unreactive ?

A

Chains of carbon atoms attached to one another by single bonds (alkanes)

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4
Q

What are functional groups ?

A

Common groupings of atoms which react in characteristic ways

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5
Q

What does R stand for ?

A

Residue

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6
Q

What does the polarity of functional groups have an impact on ?

A

The acidity or basicity of the compound and its reactivity more generally

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7
Q

How is the extent of polarisation determined by ?

A

The difference in electronegativity between two elements

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8
Q

What polarises the c-x bond ?

A

Carbon being bound to a more electronegative element

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9
Q

What is the Bronsted and Lowry’s definition of acids and bases ?

A

An acid is a substance that donates a hydrogen ion.

A base is a substance that accepts a hydrogen ion.

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10
Q

What does acid-base reactions involve ?

A

Proton transfer

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11
Q

What is Ka ?

A

The acid dissociation for an acid

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12
Q

What is the formula for Ka ?

A

Products/Reactants

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13
Q

What is the formula for pKa ?

A

pKa = -log10Ka

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14
Q

What do strong acids have ?

A

Large Ka values and therefore small pKa values

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15
Q

What is the pKa of phosphoric acid ?

A

2.2

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16
Q

What is the pKa of imidazolium ion ?

A

6.9

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17
Q

What is the pKa of ammonium ion ?

A

9.3

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18
Q

What is the pKa of thiol ?

A

10.3

19
Q

What is the pKa of B-keto ester ?

A

10.6

20
Q

What is the pKa of water ?

A

15.7

21
Q

What is the pKa of ketone ?

A

19.3

22
Q

What is the pKa of ester ?

A

25

23
Q

What is the pKa of carboxylic acid ?

A

4.8

24
Q

What is the pKa of dihydrogenphosphate ion ?

A

7.2

25
Q

What is the pKa of phenol ?

A

9.9

26
Q

What is the pKa of alkylammonium ion ?

A

10.6

27
Q

What is the pKa of alcohol ?

A

16

28
Q

What is the pKa of thioester ?

A

21

29
Q

What is lewis’ definition of acids and bases ?

A

An acid is an electron pair acceptor.

A base is an electron pair donor

30
Q

How do molecules react in solution ?

A
  1. Molecules must diffuse through solution and encounter one another before they can react.
  2. When molecules approach one another, they must collide with enough energy to overcome intermolecular repulsion and with the correct orientation
31
Q

What do polar reactions involve ?

A

The flow of pairs of electrons from areas of high electron densities to areas of low electron density

32
Q

What is a chemical reaction that is considered spontaneous ?

A

Delta G is less than zero

33
Q

How is Gibbs free energy related to the equilibrium constant ?

A

∆G = -RTlnK

34
Q

What can the favourability of reactions be driven by ?

A
  1. Making enthalpy more negative

2. Making entropy more positive

35
Q

What is the equation for Gibbs Energy ?

A

∆G = ∆H -T∆S

36
Q

What is the symbol for enthalpy ?

A

Delta H

37
Q

What is the symbol for entropy ?

A

Delta S

38
Q

How would making the enthalpy more negative work ?

A

Breaking bonds requires energy and making bonds releases energy, so forming stronger, more stable bonds provides an enthalpic driving force

39
Q

How would making entropy more positive work ?

A
  1. Increasing the number of particles increases the disorder of the system
  2. Solvation effects - localised charges can be strongly solvates, which orders the solvent which can contribute towards a lower entropy
40
Q

What does the reaction mechanism show ?

A

The individual steps in chemical reactions

41
Q

What do curly arrows show ?

A

The movement of a pair of electrons in reaction mechanisms

42
Q

What is a nucleophile ?

A

Donor of electron pairs

43
Q

What is an electrophile ?

A

An acceptor of a pair of electrons