module 4

Question 1

define the term hydrocarbon

Answer 1

A hydrocarbon is a compound containing carbon and hydrogen only

Question 2

define the term fuctional group

Answer 2

A functional group is the part of the organic the molecule that is largely responsible for the molecule’s chemical properties

Question 3

define the term homologous series

Answer 3

A homologous series is a family of compounds with
the same functional group and similar chemical
properties
whose successive members differ by the addition of
a –CH2– group

Question 4

define the term homolytic fission

Answer 4

In homolytic fission, a covalent bond is breaks with
each bonded atoms takes one of the shared pair of
electrons from the bond.
e.g. H3C–CH3 → H3C• + •CH3

Question 5

define the term heterolytic fission

Answer 5

In heterolytic fission, a covalent bond is breaks with
one of the bonded atoms taking both of the
electrons from the bond.
e.g. H3C–Cl → H3C+ + Cl–

Question 6

define the term structural isomers

Answer 6

Structural isomers are compounds with the same

molecular formula but different structural formulae and arrangements in space

Question 7

define the term empirical formula

Answer 7

The empirical formula is the simplest whole-number
ratio of the atoms of each element present in a
compound

Question 8

define the term structural formula

Answer 8

The general formula is the simplest algebraic

formula for any member of a homologous series

Question 9

define the term displayed formula

Answer 9

A displayed formula shows the relative positioning
of all of the atoms in a molecule and the bonds
between them

Question 10

define the term skeletal formula

Answer 10

The skeletal formula is the simplified organic
formula, shown by removing hydrogen atoms from
alkyl chains, leaving just a carbon skeleton and
associated functional groups

Question 11

define the term electrophile

Answer 11

An electrophile is an electron pair acceptor, e.g. Br2

Question 12

define the term nucleophile

Answer 12

A nucleophile is an electron pair donor, e.g. OH–

Question 13

define the term radical

Answer 13

A radical is an atom or groups of atoms with an

unpaired electron, e.g. Cl•

Question 14

define the term saturated

Answer 14

A compound with a carbon to carbon multiple bond

double or triple bond

Question 15

effect on chain length on boiling point

Answer 15

increased chain length =

• greater London forces
• larger surface area of contact

Question 16

effect on branching on boiling point

Answer 16

more branching =

• weaket London forces
• smaller surface area of contact

Question 17

Complete combustion of alkanes formula

Answer 17

CxHy + (x + y/4) O2 —> xCO2 + y/2 H2O

Question 18

What overap does a pi bond have

Answer 18

Sidewards overlap

Question 19

Conditions for E/Z isomerism

Answer 19

• a C=C double bond

- different groups attached to each carbon atom of the double carbon to carbon bond

Question 20

Difference between cis-trans and E/Z

Answer 20

cis-trans needs one of the attached groups to be the same

Question 21

Test for unsaturation

Answer 21

(Bromine water test)
Add bromine water (orange colour) to the solution
If the solution turns from orange to colour then the solution was unsaturated meaning there was a C=C double bond present.
If there was no colour change then there was no unsaturated compund present.

Question 22

define the term dehydration

Answer 22

a reaction in which a water molecule is removed from the starting material

Question 23

define the term nucleophiles and give examples

Answer 23

species that donate a lone pair of electrons
OH-
H2O
NH3

Question 24

1-chlorobutane observation

Answer 24

a white precipitate forms very slowly

Question 25

1-bromobutane observation

Answer 25

a cream precipitate forms slower than 1-iodobutane but faster than 1-chlorobutane

Question 26

1-iodobutane observation

Answer 26

a yellow precipitate forms rapidly

Question 27

use of anhydrous calcium chloride

Answer 27

drying hydrocarbons

Question 28

use of anhydrous calcium sulfate

Answer 28

general drying

Question 29

use of anhydrous magnesium sulfate

Answer 29

general drying

Question 30

define the term fragmentation

Answer 30

in the mass spectrometer, some molecular ions breaking down into smaller pieces knows as fragments.

Question 31

define the term elemental analysis

Answer 31

use of percentage composition data to deternmine the empirical formula

Question 32

define the term mass spectrometry

Answer 32

use of the molecular ion peak from a mass spectrum to determine the molecular mass; use of fragment ions to identify sections of a molecule

Question 33

define the term infrared spectroscopy

Answer 33

use of absorptions peaks from an infrared spectrum to identify bonds and functional groups present in the molecule

Question 34

define the term aliphatic

Answer 34

carbon atoms are joined to each other in unbranced or branched chains, or non-aromatic rings

Question 35

define the term alicyclic

Answer 35

carbon atoms are joined to eachother in ring structures (cyclic). some with or without branches

Question 36

define the term aromatic

Answer 36

some or all of the carbon atoms are found within a benzene ring