Alkanes

Question 1

What is the name of the first alkane?

Answer 1

methane

Question 2

What is the name of the second alkane?

Answer 2

ethane

Question 3

What is the name of the third alkane?

Answer 3

propane

Question 4

What is the name of the fourth alkane?

Answer 4

butane

Question 5

What is the name of the fifth alkane?

Answer 5

pentane

Question 6

What is the name of the sixth alkane?

Answer 6

hexane

Question 7

What is the name of the seventh alkane?

Answer 7

heptane

Question 8

What is the name of the eighth alkane?

Answer 8

octane

Question 9

What is the name of the ninth alkane?

Answer 9

nonane

Question 10

What is the name of the tenth alkane?

Answer 10

decane

Question 11

What are the general characteristics of a homologous series?

Answer 11

All members can be represented by a single general molecular formula. The structure of each member differs by CH2 each time. Physical properties show a steady change with increasing molar mass. Adjacent members become more alike with increasing molar mass.

Question 12

Define structural formula.

Answer 12

The minimal detail that shows arrangement of atoms

Question 13

Define General formula.

Answer 13

The simplest algebraic formula of a member of a homologous series

Question 14

Define displayed formula.

Answer 14

The relative positioning of atoms and the bonds between them

Question 15

Define skeletal formula.

Answer 15

The simplified organic formula shown by removing hydrogen atoms leaving just a carbon skeleton

Question 16

What is the general formula of an alkane?

Answer 16

CnH2n+2

Question 17

What is the general formula for cycloalkanes?

Answer 17

CnH2n

Question 18

Define empirical formula.

Answer 18

The simplest whole number ratio of atoms of each element present in a compound.

Question 19

Define molecular formula.

Answer 19

The actual number of atoms of each element in a molecule.

Question 20

Define homologous series.

Answer 20

A series of organic compounds that have the same functional group but with each successive member differing by CH2

Question 21

Define the term functional group.

Answer 21

A group of atoms responsible for the characteristic reactions of a compound.

Question 22

What does aliphatic mean?

Answer 22

A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings.

Question 23

Define the term structural isomer.

Answer 23

Two molecules that have the same molecular formula but a different structural arrangement.

Question 24

True or false? Cycloalkanes react like an alkane.

Answer 24

True

Question 25

What is combustion?

Answer 25

A chemical reaction where something burns in oxygen to release light and heat energy.

Question 26

Give three possible sources of ignition.

Answer 26

Heat, friction, electricity.

Question 27

Give two pieces of information about the way that hydrocarbons burn.

Answer 27

They burn relatively cleanly and they release a lot of energy.

Question 28

What is the equation for full combustion?

Answer 28

Fuel + oxygen ---\> carbon dioxide + water

Question 29

What products may be given off if incomplete combustion occurs?

Answer 29

Carbon + water, carbon monoxide + water, hydrocarbon + water.

Question 30

What is the functional group of an alkene?

Answer 30

C=C

Question 31

What is the functional group of an alcohol?

Answer 31

-OH

Question 32

What is the functional group of a haloalkane?

Answer 32

-Cl -Br -I

Question 33

What is the functional group of an aldehyde?

Answer 33

-CHO (double bond between carbon and oxygen.

Question 34

What is the functional group of a ketone?

Answer 34

-C(CO)C- (double bond to oxygen on the middle carbon

Question 35

What is the functional group of a carboxylic acid?

Answer 35

-COOH

Question 36

What is the prefix/suffix of an alkene?

Answer 36

-ene

Question 37

What is the prefix/suffix of an alcohol?

Answer 37

hydroxyl- -ol

Question 38

What is the prefix/suffix of a haloalkane?

Answer 38

chloro- bromo- iodo-

Question 39

What is the prefix/suffix of an aldehyde?

Answer 39

-al

Question 40

What is the prefix/suffix of a ketone?

Answer 40

-one

Question 41

What is the prefix/suffix of a carboxylic acid?

Answer 41

-oic acid

Question 42

Which of these two conformations is the most stable? Why?

Answer 42

The first one because the hydrogen atoms can be the furthest apart from eachother.

Question 43

What type of bonds join the carbon and hydrogen atoms in a hydrocarbon?

Answer 43

Covalent bonds.

Question 44

True or false? The covalent bonds in a hydrocarbon are very strong and prevent the molecule of ethane breaking up into carbon and hydrogen again.

Answer 44

True

Question 45

What is the name given to the forces that attract separate molecules of ethane to each other?

Answer 45

Intermolecular forces called London Dispersion forces.

Question 46

What happenes to the bonds and forces when a liquid boils?

Answer 46

The weak intermolecular forces get broken allowing individual molecules to separate away from eachother to become a gas. The covalent bonds are still intact.

Question 47

What is the boiling point of a liquid?

Answer 47

A measure of how much heat energy we need to overcome its intermolecular forces.

Question 48

Fill in the blanks. Smaller hydrocarbons have _____ intermolecular forces between each molecule.

Answer 48

Fewer

Question 49

Fill in the blanks. Smaller molecules require _____ heat energy to break the forces and turn the liquid into a gas.

Answer 49

Less

Question 50

Fill in the blanks. Smaller hydrocarbons have a _____ boiling point than larger hydrocarbons

Answer 50

Lower

Question 51

Explain why an alkane with side branches will have a lower boiling point than a straight chain alkane with the same number of carbon atoms.

Answer 51

An alkane with side branches will have a lower boiling point than a straight chain alkane with the same number of carbon atoms because there will be less points of contact between molecules which means that it is harder to induce a dipole and therefore there are less forces of attraction.

Question 54

Describe the process of free radical substitution.

Answer 54

* Step 1 (initiation) - covalent bond in a bromine molecule is broken by hydrolytic fission. Each bromine atom takes one of the unpaired electrons forming two highly reactive radicals. Energy provided by UV light. * Step 2 (propagation step 1) - a bromine radical reacts with the methane forming a methyl radical and a molecule of hydrogen bromide. CH₄ + Br• → CH₃• + HBr * Step 2 (propagation step 2) - Each methyl radical racts with another bromine molecule forming bromomethane and a new bromine radical. CH₃• + Br₂ → CH₃Br + Br• * The two steps continue until two radicals collide * Step 3 (termination) - Two radicals collide to form a molecule with all electrons paired. Number of possible termination steps. (Br• + Br• → Br₂) (CH₃• + CH₃• → C₂H₆) (CH₃• + Br• → CH₃Br)

Question 55

What is the name of this shape?

Answer 55

Trigonal planar

Question 56

What is the name of this shape?

Answer 56

tetrahedral