Book 2: Definitions Flashcards
Mineral acids
Acids that are derived from minerals
Base
A substance that reacts with an acid to form a salt and water only.
Neutralisation
The combination of hydrogen ions and hydroxide ions (or oxide ions) to form water molecules.
Effervescence
Bubbling
Acid
A compound which produces hydrogen ions as the only positive ions when dissolved in water.
Basicity
The maximum number of hydrogen ions that can be produced by one molecule of the acid.
Alkalis
Bases which are soluble in water and produce hydroxide ions when dissolved in water.
Hygroscopic substances
Substances which absorb water vapour from air
Deliquescent substances
Substances which absorb water vapour from air and eventually form a very concentration solution.
Acidic solution
A solution with pH less than 7
Alkaline solution
A solution with pH above 7
Neutral solution
A solution with pH equal to 7
Strong acid
An acid that dissociates almost completely in water to give hydrogen ions.
Weak acid
An acid that dissociates partially in water to give hydrogen ions.
Strong alkali
An alkali that dissociates almost completely in water to give hydroxide ions.
Weak alkali
An alkali that dissociates partially in water to give hydroxide ions.
Acid salt
A salt formed by replacing only part of the hydrogen ions from an acid.
Normal salt
A salt formed by replacing all of the hydrogen ions from an acid.
Standard solution
A solution whose concentration is accurately known.
Titre
The volume delivered from the burette into the conical flask until the titration end point is reached.
Concordant titres
Titres pairwise within 0.10cm3 of each other.
Titration end point
The point at which the indicator changes colour.
Equivalence point
The point at which sufficient acid has been added to just neutralise the alkali (or vice versa).
Chemical cell
A device that converts the chemical energy stored in it into electrical energy.
Negative electrode
The electrode from which electrons flow into the external circuit.
Positive electrode
The electrode from which electrons flow from the external circuit.
Electrolyte
The medium which allows ions to flow between the two electrodes.
Primary cell
Chemical cell that cannot be recharged
Secondary cell
Chemical cell that can be recharged
Cell capacity
Number of hours a cell can supply a particular amount of electric current (ampere-hours)
Energy density
The amount of energy that can be derived per unit volume of the cell
Service life
The length of time that a cell can remain in use before its voltage drops to a certain value (usually 0.8V)
Cycle life
The number of charge-discharge cycles that a secondary cell can undergo before its capacity falls to 80% of its original value
Shelf life
The length of time that a cell can be stored inactive before its capacity falls to 90% of its original value.
Salt bridge
A strip of filter paper soaked in an electrolyte and dipped in the solutions, to complete an electric circuit built from two half-cells
Porous pot
A replacement of the salt bridge in the Daniell cell
Oxidation in terms of gain and loss of oxygen
The gain of oxygen by a chemical species.
Reduction in terms of gain and loss of oxygen
The loss of oxygen from a chemical species.
Redox reaction
A reaction in which reduction and oxidation take place.
Oxidising agent
A chemical species that causes oxidation of another chemical species, and becomes reduced in the process.
Reducing agent
A chemical species that causes reduction of another chemical species, and becomes oxidised in the process.
Oxidation in terms of gain and loss of hydrogen
The loss of hydrogen from a chemical species.
Reduction in terms of gain and loss of hydrogen
The gain of hydrogen by a chemical species.
Oxidation in terms of gain and loss of electrons
The loss of electron(s) from a chemical species.
Reduction in terms of gain and loss of electrons
The gain of electron(s) by a chemical species.
Oxidation in terms of gain and loss of electrons in oxidation numbers
The oxidation number of an element in a chemical species increases.
Reduction in terms of gain and loss of electrons in oxidation numbers
The oxidation number of an element in a chemical species decreases.
Stock system
A system which uses the concept of oxidation number to name inorganic compounds.
Breathalyser
A breath test machine to detect and estimate alcohol levels
Disproportionation reaction
A reaction in which one element has been both oxidised and reduced, so that its oxidation number increases and decreases at the same time.
Anode
The electrode at which oxidation occurs
Cathode
The electrode at which reduction occurs
Fuel cell
A chemical cell in which the reactants can be supplied continuously and the products of the cell reaction are continuously removed.
Electrolysis
The process of decomposing an electrolyte with an electric current
Electrolytic cell
The apparatus in which electrolysis is carried out
Electronegativity
A measure of the ability of an atom of the element to attract the bonding electrons in a covalent bond towards itself.
Dipole
A separation of opposite electrical charges
Induction
The process in which a temporary dipole affects the electron distribution of a neighbouring molecule, resulting in the formation of another dipole.
Hydrogen bond
The strong attractive force between a hydrogen atom attached to a highly electronegative atom and the lone pair on another electronegative atom.
Viscosity
A quantity that describes a liquid’s resistance to flow
