Chemistry (Science June)

Hydrocarbon:

organic compounds that consist of hydrogen and carbon only. 

Homologous series:

series of organic compounds that can be described by the same general formula OR in which one member differs from the next with a CH2 group 

Saturated compounds: 

compounds in which there are no multiple bonds between C atoms in their hydrocarbon chains  

Unsaturated compounds:

compounds with one or more multiple bonds between C atoms in their hydrocarbon chains  

Functional group: 

a bond or an atom or a group of atoms that determine(s) the physical and chemical properties of a group of organic compounds 

Structural isomer: 

same molecular formula, but different structural formulae 

Positional isomers:

Same molecular formula, but different positions of the side chain, substituents or functional groups on the parent chain, 

Functional isomers:

Same molecular formula, but different functional groups, 

Boiling point: 

The temperature at which the vapour pressure of a substance equals atmospheric pressure.  

Melting point: 

The temperature at which the solid and liquid phases of a substance are at equilibrium.  

Vapour pressure:   

The pressure exerted by a vapour at equilibrium with its liquid in a closed system. 

Heat of reaction (ΔH):

The energy absorbed or released in a chemical reaction. 

Exothermic reactions:

Reactions that release energy.

Endothermic reactions: 

Reactions that absorb energy.

Activation energy:

The minimum energy needed for a reaction to take place.

Activated complex:

The unstable transition state from reactants to products.

Arrhenius Acids

Acids produce hydrogen ions (H⁺/H₃O⁺/hydronium ions) in aqueous solution.   

Arrhenius base

Bases produce hydroxide ions (OH^-) in aqueous solution. 

Lowry-Brønsted Acid:

An acid is a proton (H⁺ion) donor.  

Lowry-Bronsted Acid:

A base is a proton (H⁺ion) acceptor. 

Hydrolysis: 

The reaction of a salt with water. 

Equivalence point of a titration:

The point at which the acid/base has completely reacted with the base/acid.  

Endpoint of a titration:

The point where the indicator changes colour

Reaction Rate: 

the change in concentration of reactants or products per unit time.

Catalyst:

a substance that increases the rate of a chemical reaction without itself undergoing a permanent change 

Open and closed systems:

an open system continuously interacts with its environment, while a closed system is isolated from its surroundings.  

Le Chatelier's principle: 

When the equilibrium in a closed system is disturbed, the system will re-instate a new equilibrium by favouring the reaction that will oppose the disturbance. 

Reversible reaction:

products can be converted back to reactants and vice versa. 

Chemical equilibrium:

a dynamic equilibrium when the rate of the forward reaction equals the rate of the reverse reaction.  

Oxidation:

loss of electrons OR an increase in oxidation number 

Reduction:

gain of electrons OR a decrease in oxidation number

Oxidising agent:

a substance that is reduced/gains electrons 

Reducing agent:

a substance that is oxidised/loses electrons. 

Anode:

the electrode where oxidation takes place

Cathode:

the electrode where reduction takes place

Electrolyte:

a substance of which the aqueous solution contains ions OR a substance that dissolves in water to give a solution that conducts electricity.