Chemistry (P2) - Structure and Formulae

Label this diagram

A - empirical formula
B - molecular formula

How do we deduce the empirical formula of an organic compound?

We need the elements present in the compound and the mass of each element in the compound. We use the mass to find the number of moles of each element and create a mole ratio that, once simplified, would be equal to the proportions in the empirical formula

How do we deduce the molecular formula of an organic compound?

We need the empirical formula, molar mass of the compound and the mass of each element in the compound. We find the mass of the empirical formula and then we use it as a divisor with the molar mass of the compound and multiple the number of each atom in the empirical formula by the quotient

Label this diagram

A - displayed
B - condensed

Identify this diagram

Cyclohexane

Label this diagram

A - alkene
B - alcohol
C - halogenoalkane
D - carboxylic acid

List the properties of a homologous series

1. There is a general formula which applies to all members in the series

2. Each successive member increases by the unit —CH2

3. The members have similar chemical properties due to having the same functional group

4. The physical properties gradually increase along with the amount of bonds present in the compound

Label this diagram

A - meth
B - eth
C - prop
D - but
E - pent
F - hex
G - hept
H - oct
I - non
J - dec

Label this diagram

A - alkane
B - alkene
C - alcohol
D - carboxylic acid
E - ketone

List the rules of naming branched chains

1. The longest possible chain of atoms is always the main branch

2. The position of side branches are shown by numbering the carbon atoms

3. Carbon atoms are numbered starting at the end that gives the smallest number possible for the branch

4. A prefix is added to the stem to indicate the branch, which is named based on the amount of carbon atoms it contains

5. The position of the branch prefaces the prefix

Label this diagram

A - position of side chain
B - prefix
C - stem

Identify this diagram

2-chloro-1-iodopropane

Which phenomenon allows organic compounds to have their chain structure?

Catenation

Which properties of carbon contribute to the structure of organic compounds?

The size of the carbon atom increases its effective nuclear charge, making the covalent bonds it breaks relatively hard to break, allowing the compound stability

The orbitals of carbon atoms hybridize allowing it to exhibit tetravalency which allows carbon atoms to form bonds in four directions, particularly contributing to the occurrence of branched and ring chains

How does resonance contribute to the stability of an organic compounds?

A delocalized system of electrons between atoms reduces the electron density concentrated around a singular atom and distributes it more easily which, decreasing the risk of an attack from an electrophilic species and also reducing repulsion between electrons, increasing the stability of the compound

Identity the phenomenon in this diagram

chain isomerism

Identify the phenomenon in this diagram

functional isomerism

Identify the phenomenon in this diagram

Identify the phenomenon in this diagram

Geometrical isomerism

What causes geometric isomers and how do we differentiate between them?

Geometric isomers occur because there is no free rotation about a double bond, unlike with single bonds. If the two atoms are on the same side, the prefix cis- is attached to the compound otherwise the prefix trans- is attached

What causes optical isomers

Optical isomers rotate plane-polarised light in opposite directions by an equal amount as the electromagnetic field in plane polarised light only vibrates in one plane

State the steps for drawing all the isomers of a compound