Component 2 additional knowledge (beyond GCSE) (copy) (copy)

Definition of enthalpy change of reaction

is the enthalpy change when the molar quantities of reactants, as stated in the balanced equation, react under standard condition

Definition of enthalpy change of combustion

is the enthalpy change when one mole of a substance burns completely in oxygen under standard conditions.

Definition of enthalpy change of formation

is the enthalpy change when one mole of a compound is formed from its elements, in their standard states, under standard conditions.

Define Hess' Law

that the enthalpy change converting reactants to products is the same regardless of the route taken provided the initial and final conditions are the same.

Define bond energy

is the energy required to break one mole of that particular bond in the gaseous state.

Defin enthalpy change

is the overall energy exchanged with the surroundings when a change happens at constant pressure and the final temperature is the same as the starting temperature.

Define exothermic

there is a net transfer of energy from the system to the surroundings.

Define endothermic

there is a net transfer of energy from the surroundings to the system.

Sign for exothermic is

negative

Sign for endothermic is

positive

Define calorimetry

the measurement of energy changes of a system by measuring their effect on surroundings.

Define specific heat capacity

the energy needed to raise the temperature of 1g of the material by 1K

Calorimetry equation

q= mc∆T

Standard conditions are

1 mol dm-3 100kPa 298K

Define rate of reaction

Amount of chemical change per unit time

Factors affecting rate

Concentration (pressure), surface area, temperature, catalyst

Define catalyst

a substance that speeds up a reaction by providing an alternative pathway of lower activation energy. The substance is not consumed in the process.

Define transition state

this is the point where energetically all of the energy added breaks bonds. It does not exist in isolation so cannot be extracted or detected.

Define intermediate

a temporary substance formed in a reaction that can be isolated.

Heterogeneous catalyst

reactants and catalyst are in different phases

Homogeneous catalyst

reactants and catalyst are in the same phase

Equations for oxidation of iodide ions by peroxodisulphate using iron

Equations for autocatalysis of ethanedioate with manganate (VII)

Green chemistry

An approach by chemists to reduce the environmental impact of chemical proceses. Whether that is reducing energy or using/producing chemicals that produce less waste or uses/produces less toxic materials.

Skeletal formulae

A formula that shows just the carbon backbone and any functional group.

Carboxylic acid prefix

Carboxy-

Aldehydes prefix

formyl

Ketones prefix

Oxo-

Esters prefix

alkoxycarbonyl

Amide prefix

carbamoyl

Alkene prefix

alkenyl

Alcohols prefix

Hydroxy-

Amines prefix

Amino-

Alkane (and branches) prefix

-yl e.g. Methyl

Halogeno prefix

eg Chloro-

Nitrile prefix

Cyano-

Alkyne prefix

Alkynyl

Carboxylic acid suffix

-oic acid

Aldehydes suffix

-al

Ketones suffix

-one

Esters suffix

-oate

Amide suffix

-amide

Alkene suffix

-ene

Alcohols suffix

-ol

Amines suffix

-amine

Alkane (and branches) suffix

-ane

Nitrile suffix

nitrile

Alkyn suffix

yne

Addition

Two or more substances reacting to form one.

Substitution

Part of one molecule swapping place with a part of another.

Elimination

One compound releasing a small molecule and forming an unsaturated compound.

Hydrolysis

Using water to break a bond (sometimes using acids or bases as a catalyst).

Polymerisation

Where one or more monomer units join to form a long repeating chain.

Oxidation

Addition or oxygen or removal of hydrogen

Reduction

Removal of oxygen or addition of hydrogen

Electrophile

A lone-pair acceptor

Nucleophile

A lone-pair donor

Radical

A highly excited species with an unpaired electron (formed from homolytic fission)

Homolytic fission

Where a covalent bond splits equally with each species taking one electron

Heterolytic fission

Where a covalent bond splits unevenly (most common form of bond breaking in organic chemistry)

monomer

a single unit from which a polymer is built

polymer

a long chain of repeating units

repeating unit

a short-hand way of showing what repeats within the polymer

Primary classification

Where the ---------- is attached to a carbon that is attached to just one other carbon.

Secondary classification

Where the ---------- is attached to a carbon that is attached to two other carbons.

Tertiary classification

Where the ---------- is attached to a carbon that is attached to three other carbons.

Reflux

the continuous vapourisation and condensation of a substance using a vertically fitted condenser.

Hydrolysis

the splitting of part of a compound using water.

Standard answer for IR questions

the peak at pick a value is in the region …….cm-1 to …….cm-1 this suggest that this is a [type of bond] from a ……….

Exothermic energy level diagram

Endothermic energy level diagram

Carboxylic Acid

Aldehyde

ketone

Ester

Amide

Alkene

Alcohol

Amine

Acid anhydride

Acid chloride

Nitrile

Alkyne