Basic Concepts

Question 1

Definition of a hydrocarbon

Answer 1

A compound containing hydrogen and carbon atoms only.

Question 2

What bonds do saturated hydrocarbons contain?

Answer 2

Only single carbon-carbon bonds.

Question 3

What bonds do unsaturated hydrocarbons contain?

Answer 3

Carbon-carbon multiple bonds.

Question 4

Definition of a homologous series

Answer 4

A family of molecules possessing the same functional group, where each successive member diffes by -CH2.

Question 5

Definition of functional groups

Answer 5

An atom or group of atoms that provide the characteristic chemical reactions of a molecule.

Question 6

Definition of aliphatic hydrocarbons

Answer 6

Carbon atoms joined to each other in unbranched (straight) or branched chains, or non-aromatic rings.

Question 7

Definition of alicyclic hydrocarbons

Answer 7

Carbon atoms are joined to each other in ring (cyclic) structures, with or without branches.

Question 8

Definition of aromatic hydrocarbons

Answer 8

Some or all of the carbon atoms are found in a benzene ring.

Question 9

What are the three homologous series of aliphatic hydrocarbons?

Answer 9

1. Alkanes- containing only single carbon-carbon bonds.
2. Alkenes- containing at least one double carbon-carbon bond.
3. Alkynes- containing at least on triple carbon-carbon bond.

Question 10

Definition of molecular formula (2 points).

Answer 10

1. This shows the number and type of atoms of each elemnt present in a molecule.
2. The molecular formula doesn’t show how the atoms are joined together and different molecules can have the same molecular formula.

Question 11

Definition of empirical formula

Answer 11

This is the simplest whole number ratio of the atoms of each element present in a compound.

Question 12

Definition of general formula (2 points).

Answer 12

1. This is the simplest algebraic formula for any member of a homologous series.
2. This formula can be used to generate the molecular formula for any member of that homologous series.

Question 13

Definition of displayed formula

Answer 13

This shows the relative positioning of all the atoms in a molecule and the bonds between them.

Question 14

Definition of structural formula (2 points).

Answer 14

1. This formula uses the smallest amount of detail necessary to show the arrangement of the atoms in a molecule.
2. It shows clearly which atoms are bonded together.

Question 15

Definition of skeletal formula (3 points).

Answer 15

1. This is a simplified organic formula.
2. All of the carbon and hydrogen labels from the carbon chains and any bonds to the hydrogens are removed.
3. This leaves a carbon skeleton and any functional groups.

Question 16

Definition of structural isomers

Answer 16

Compounds with the same molecular formula but different structural formulae.

Question 17

Definition of homolytic fission

Answer 17

Breaking of covalent bond, with each bonding atom recieving one electron from the bonded pair, formig 2 radicals.

Question 18

What is a radical?

Answer 18

A species with an unpaired electron.

Question 19

Definition of heterolytic fission

Answer 19

The breaking of a covalent bond with one bonding atom recieving both electrons from the bonded pair, forming a cation and an anion.

Question 20

Explain what an addition reaction is

Answer 20

Two reactants join togther to form one product.

Question 21

Explain what a substitution reaction is

Answer 21

An atom or group of atoms is replaced by a different atom or group of atoms.

Question 22

Explain what an elimination reaction is

Answer 22

Involves the removal of a small molecule from a larger one.

Question 23

Definition of theoretical yield and equation of percentge yield

Answer 23

The maximum possible amount of product.
% yield = (actual yield / theoretical yield) x 100

Question 24

Explain why it is difficult to achieve 100% of theoretical yield (3 points).

Answer 24

1. The reaction may not have been completed.
2. Other reactions may have taken place.
3. Purification of the product may result in loss of some product.

Question 24

Explain why it is difficult to achieve 100% of theoretical yield (3 points).

Answer 24

1. The reaction may not have been completed. 2. Other reactions may have taken place. 3. Purification of the product may result in loss of some product.

Question 25

What is a limiting reactant?

Answer 25

The reactant that is not in excess will be completely used up first and stop the reaction.

Question 26

Definition of atom economy

Answer 26

The atom economy of a chemical reaction is a measure of how well atoms have been utilised.

Question 27

What features do reactions with high atom economies have?

Answer 27

1. Produce a large proportion of desired products and few unwanted waste products. 2. Are important for sustainability as they make the best use for natural resources.

Question 27

What features do reactions with high atom economies have? (2 points).

Answer 27

1. Produce a large proportion of desired products and few unwanted waste products. 2. Are important for sustainability as they make the best use for natural resources.

Question 28

Atom economy equation

Answer 28

Atom economy = (sum of molar masses of desired products) / (sum of molar masses of all products) x 100