Overview of Organic Reactions

Question 1

What are addition reactions?

Answer 1

Two reactants combining to form a single product.

Question 1

What are elimination reactions?

Answer 1

Single reactant splitting into two products.

Question 2

What are substitution reactions?

Answer 2

Two reactants exchanging parts to form two new products.

Question 3

What are rearrangement reactions?

Answer 3

Single reactant yielding an isomeric product through reorganization of its bonds and atoms.

Question 4

Define reaction mechanism.

Answer 4

Overall description of a reaction process.

Question 5

What is involved in chemical reactions?

Answer 5

Bond breaking and bond making

Question 6

What is it called when a reaction results in symmetrical bond breaking/forming?

Answer 6

Homolytic

Question 7

What is it called when a reaction involves unsymmetrical breaking/forming of bonds?

Answer 7

Heterolytic

Question 8

What do curved arrows indicate?

Answer 8

Breaking and forming of bonds

Question 9

What do fish-hook arrowheads indicate?

Answer 9

Movement of one electron in the symmetrical process.

Question 10

What do arrowheads with complete heads indicate?

Answer 10

Movement of two electrons in the unsymmetrical process.

Question 11

What are radical reactions?

Answer 11

Processes that involve symmetrical bond-breaking and bond-making.

Question 12

What are polar reactions?

Answer 12

Processes involving unsymmetrical bond-breaking and making.

Question 13

What is a radical?

Answer 13

A neutral chemical species containing odd number of electrons. Has a single, unpaired electron in one of its orbitals.

Question 14

What is more common, radical or polar reactions?

Answer 14

Polar

Question 15

What happens when radicals react?

Answer 15

Complete electron octet of valence shell.

Question 16

What are the steps of radical reactions?

Answer 16

1. Initiation
2. Propagation
3. Termination

Question 17

What is propagation of radical reactions?

Answer 17

Reaction with one molecule to generate a radical.

Question 18

What is termination of a radical reaction?

Answer 18

Combination of two radicals to form a stable product.

Question 19

What causes bond polarity?

Answer 19

Molecules with unsymmetrical electron distributions

Question 20

What is polarizability?

Answer 20

Tendency of atoms to undergo polarization

Question 21

What causes electron distribution around atoms to change?

Answer 21

Solvents or other nearby polar molecules

Question 22

Differentiate between the polarizability of larger and smaller atoms.

Answer 22

Larger atoms, more loosely held electrons, easily polarizable.
Smaller atoms, more tightly held electrons, less polarizable.

Question 23

What is an additional way for polar bonds to form?

Answer 23

From the interaction of functional groups with acids or bases.

Question 24

What is a nucleophile?

Answer 24

Electron-rich species that donate electron pairs to electrophile in a polar bond-forming reaction.
A lewis base.

Question 25

What is an electrophile?

Answer 25

Substance that accepts electron pairs from a nucleophile
A Lewis acid

Question 26

Which is more accessible to approaching reactants: double bond or single bond?

Answer 26

Double bond

Question 27

How do polar reactions occur?

Answer 27

By combination of an electron-rich site of a nucleophile and an electron-deficient site of an electrophile.

Question 28

What is a carbocation?

Answer 28

Substance that contains a trivalent, positively charged carbon atoms having six electrons in its outer shell.

Question 29

What are the rules for curved arrows?

Answer 29

1. Electrons move from a nucleophilic source to an electrophilic sink
   2, The nucleophilic site can be neutral or negatively charged.
2. The electrophilic site can be neutral or positively charged
3. The octet rule should be followed.

Question 30

How do you determine the equlibrium constant?

Answer 30

Multiplied concentration of products divided by multiplied concentrations of reactant
Each concentration raised to the power of its coefficient

Question 31

What does a Keq value of more than one mean?

Answer 31

Indicates product concentration is larger than reactant concentration term
Reaction takes place from left to right

Question 32

What does it mean if Keq is 1?

Answer 32

Quantity of reactant and product present at equilibrium are equal

Question 33

What does it mean if Keq is less than 1?

Answer 33

Reaction takes place in reverse direction.

Question 34

Generally, what does a Keq value of more than 10^3 mean?

Answer 34

Amount of reactant is barely detectable (<0.1%).

Question 35

What is Gibbs free energy?

Answer 35

Change in energy that occurs during a chemical reaction.

Question 36

On which side is energy released in an equilibrium reaction?

Answer 36

Favoured side

Question 37

What is exergonic?

Answer 37

Reaction that has negative free energy change and is spontaneous.
Energy is lost

Question 38

What is endergonic?

Answer 38

Reaction that has a positive free energy change
Energy is absorbed

Question 39

What is a transition state?

Answer 39

Highest energy point in a reaction step.

Question 40

What is activation energy?

Answer 40

Energy required to go from reactant to transition state.

Question 41

What does activation energy determine?

Answer 41

How fast reaction occurs at a given temp

Question 42

What does a large vs. small activation energy indicate?

Answer 42

Large = slow
SMall = fast

Question 43

What might happen when the transition state is reached?

Answer 43

1. Continue to give the carbocation product
2. Revert back to reactants

Question 44

What is a reaction intermediate?

Answer 44

Species involved in a multi-step reaction that are neither the reactant nor the final product.

Question 45

What is the equation for standard free energy change?

Answer 45

= -RTlnKeq