Introduction to Organics

Question 1

What is organic chemistry?

Answer 1

The study of the structure, composition, properties, preparation and reactions of chemical compounds of carbon

Question 2

What is catenation?

Answer 2

An elements ability to form bonds with atoms of the same element

Question 3

What is the ability of an element to form bonds with atoms of the same element called?

Answer 3

Catenation

Question 4

Describe the valency of carbon.

Answer 4

Tetravalency

Question 5

Why does catenation occur so readily in carbon?

3

Answer 5

C is a relatively small atom

Forms covalent bonds

The C-C bond is strong

Question 6

What is the molecular formula, what does it express?

Answer 6

It expresses the number and type of atoms in a molecule

Question 7

What is the structural formula, what does it express?

Answer 7

It indicates how the atoms are arranged

Question 8

How do you use the full Lewis dot structure?

2

Answer 8

Bonds are indicated by dots
Lone pairs are indicated by dots

Eg.
__..__
H:O:H
__..__

Question 9

How do you use the Half Lewis dot structure?

2

Answer 9

Bonds are indicated by lines

Lone pairs are indicated by dots

Question 10

What is a full displayed formula?

2

Answer 10

Half Lewis Structure

Bond angles are displayed

Question 11

What is a skeletal formula?

4

Answer 11

Lines depict bonds

C and H atoms are not shown

End of each line segment is a C atom

Multiple lines represent multiple bonds

Question 12

What does a pair of two parallel lines in a skeletal structure indicate?

Answer 12

It indicates a double bond

Question 13

What does three sets of parallel lines in a skeletal structure indicate?

Answer 13

It indicates a triple bond

Question 14

What are the benefits of 3D structures?

3

Answer 14

They include information on the bond angles

They show the shape of the molecule

They display the possibility of isomers and stereoisomers

Question 15

In a 3D structure what is represented by a solid wedge?

Answer 15

Atoms above the plane of the page

Question 16

In a 3D structure what is represented by a hashed wedge?

Answer 16

Atoms below the plane of the page

Question 17

What are the disadvantages of 2D structures?

2

Answer 17

It takes time to draw correctly

It’s a poor representation of geometry

Question 18

What determines the properties and reactions of a molecule?

Answer 18

The type of bond between atoms within the molecule

Question 19

What does the type of bonds in a molecule depend on?

Answer 19

The location of electrons in that bond

Question 20

Why do atoms form bonds?

Answer 20

Because the product formed is more stable than the isolated atoms

Question 21

What are the two types of bonds?

Answer 21

Ionic bonding

Covalent bonding

Question 22

What is ionic bonding?

Answer 22

Where positively and negatively charged ions (cations/anions) are held together by electrostatic forces of attraction (oppositely charged species attract)

Question 23

What is covalent bonding?

Answer 23

This is where electron pairs are shared 50-50 between atoms

Question 24

Why can bonds not be 100% ionic?

Answer 24

Because there is always some sharing of electrons between atoms e.g 80% ionic and 20% covalent

Question 25

What is electronegativity?

Answer 25

How likely an electron is transferred from one element to another

Question 26

What does an electronegativity difference of 0.0 indicate?

Answer 26

Pure covalent

Question 27

What does an electronegativity difference between 0.1 and 0.5 indicate?

Answer 27

Non-polar covalent

Question 28

What does an electronegativity difference between 0.5 and 1.9 indicate?

Answer 28

Polar covalent

Question 29

What does an electronegativity difference of greater than 1.9 indicate?

Answer 29

Ionic

Question 30

What is a dipole moment?

Answer 30

The arrangement and behaviour of electrons that gives atoms all of their physical properties

Question 31

What does a molecules polarity depend on? | 2

Answer 31

Molecular shape The atoms electronegativity values

Question 32

How do we know which atom in the covalent bond of a molecule is negative and which is positive?

Answer 32

The atom with the greater electronegativity is the negative and the smaller electronegativity is positive

Question 33

Under what structural condition can a molecule be polar?

Answer 33

A molecule can only be polar if the structure of the molecule is not symmetric

Question 34

What can a dipole moment be used to predict? | 4

Answer 34

Compound solubility in the solvent The mechanism of a chemical reaction The optimum solvent for product separation by thin layer chromatography The best solvent for the crystallisation of a solid

Question 35

What is a solvent?

Answer 35

A liquid that serves as the medium for a chemical reaction and or acts as a reagent in a chemical reaction

Question 36

What is a nucleophile?

Answer 36

Substance that donates a lone pair of electrons in a chemical reaction

Question 37

Classify solvents.

Answer 37

Non polar Polar

Question 38

What is a non polar solvent?

Answer 38

A solvent with a small or zero dipole moment

Question 39

What is a non polar solvent best at dissolving?

Answer 39

Non-polar reactants

Question 40

Give an example of a non-polar reactant?

Answer 40

HCL

Question 41

What is a polar solvent?

Answer 41

A solvent that has a large dipole moment

Question 42

What is a polar solvent best at dissolving? | 2

Answer 42

Polar compounds Charged species such as ions

Question 43

Classify polar solvents.

Answer 43

Polar protic Polar aprotic

Question 44

What is a polar protic solvent?

Answer 44

A solvent that has a O-H or N-H bond

Question 45

Why are polar protic solvents important? | 2

Answer 45

They can participate in hydrogen bonding - powerful intermolecular force They serve as a source of protons (H+)

Question 46

Why are polar aprotic solvents important?

Answer 46

They may have H atoms but they lack O-H or N-H bonds and therefore cannot H-bond with itself

Question 47

Why are polar aprotic solvents important?

Answer 47

They don't participate in reactions but serve only as a reaction medium