definitions Flashcards
Organic molecules
molecules containing carbon
hydrocarbon
Organic compound that consists of only hydrogen and carbon
Homologous series
A series of organic compounds that can be described by the same general formula (same functional 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.
Isomer
Organic molecules with the same molecular formula, but a different structure formula
Macromolecule (plastics)
a molecule that consists of a large number of atoms
Polymer
A large molecule composed of smaller monomer units covalently bonded to each other in a repeating pattern
monomer
small organic molecule that can be covalently bonded to each other in a repeating pattern.
polymerisation
a chemical reaction in which monomer molecules join to form a polymer
Addition polymerisation
a reaction in which small molecules join to form very large molecules (by adding onto their double bonds)
eg ethene to polyethene
condensation polymerisation
monomers of two monomers with different functional groups undergo condensation reactions with the loss of small molecules, usually water
condensation polymer
a polymer formed by two monomers with different functional groups that are linked together in a condensation reaction in which a small molecule usually water is lost
exothermic reaction
reaction that releases energy
endothermic
reaction that absorbs energy
activation energy
minimum energy needed for a reaction to take place
activated complex
unstable transition state from reactants to products
reaction rate
change in concentration of reactants or products per unit time
positive catalyst
increases the rate of a chemical reaction without itself undergoing a permanent change
Open vs closed system
Open - interacts with the enviroment around it
closed- isolated from its surroundings
reversible reaction
products can be converted back into reactants
Chemical equilibrium
It is a dynamic equilibrium when the rate of the forward reaction equals the rate of the reverse reaction.
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
Arrhenius theory (acid and base)
An acid is a substance that produces hydrogen ions (H^+) / hydronium ions (H3O^+) when it dissolves in water. A base is a substance that produces hyroxide ions (OH^-) when it dissolves in water
lowry Bronsted theory
An acid is a proton (H+) donor. A base is a proton (H+) acceptor.
Strong acid:
Ionise completely in water to form a high concentration if H3O^+ inons.
HCL HNO3 H2SO4
Weak acids:
ionise incompletely (low concentration of hydronium ions) Organic acids eg ethanoic and oxalic acid
Strong bases
dissociate completely to form a high concentration of hydroxide ions eg sodium hydroxide and potassium hydroxide
Weak bases
dissociate/ ionise incompletely in water to form a low concentration of hydroxide ions. Eg ammonia, calcium carbonate, potassium carbonate, sodium hydrogen carbonate.
Hydrolysis
Reaction of alt with water
equivalence point of a titration
point at which the acid/ base has completely reacted with the base / acid
Endpoint of titration
point where the indicator changes colour
Galvanic cell
A cell in which chemical energy is converted into electrical energy. (has selfsustaining electrode reactions)
(spontaneous chemical reactions)
Electrolytic cell
Electrical energy is converted into chemical energy
Oxidising agent
A substance that is reduced (gains e)
Reducing agent
A substance that is oxidised (looses e)
Anode
electrode where oxidation takes place
Cathode.
Electrode where reduction takes place
Electrolyte
A solution that conducts electricity through the movement of ions
electrolysis
Chemical process in which electrical energy is converted to chemical energy OR
the use of electrical energy to produce a chemical change
Eutrophication
an ecosystem eg river becomes enriched with inorganic plant nutrients (fertilizer run off especially P and N) resulting in excessive plant growth. Leads to too little dissolved oxygen in the water (fish die)
