Chem definitions Flashcards
Isotopes
Atoms of the same element with same proton number but diff nucleon numbers
Empirical formula
Chemical formula that shows the simplest ratio of atom in a compound
Amphoteric property
A substance that shows both acidic and basic properties
Alkali
A compound that produces OH- ions when it is dissolved in water
Acid
A compound that produces H+ ions when it is dissolved in water
Molarity
The number of moles of … Dissolved in 1 dm3 of the solution
Diprotic acid
An acid that produces 2 mol of H+ ions for every mol of acid when it is dissolved in water
Electrolyte
An ionic substance that can conduct electricity either in aqueous or molten state and can undergo chemical changes
Weak acid
Dissociate partially in water to produce low conc of H+ ions
Catalyst
A substance that can alter the rate of reaction while itself remain chemically unchanged at the end of the reaction
Isomers
Compound with the same molecular formula, but with diff structural formulae
Antioxidant
Prevent food from being oxidised on exposure to the air which will turn them into acids with an unpleasant smell
Aspartame
Used to sweeten food
Flavouring
Improve the taste or smell of food and restore taste loss due to food processing
Msg
Bring out the flavours in many types of food
Stabilisers
Help to mix two liquids that usually do not mic together so that they form an emulsion
Thickeners
Substances that thicken food and give the food a firm, smooth and uniform texture
Heat of combustion
The heat given out when one mole of a substance is completely burnt in excess of oxygen under standard conditions
Food preservatives
A chemical that is added to food to retard the spoilage of food
Vulcanisation
Process which makes the natural rubber harder and increases its elasticity by adding sulphur
Redox reaction
Chemical reactions involving oxidation and reduction occuring simultaneously
Heat of precipitation
The heat change when one mole of a precipitate is formed from their ions in aqueous solution
Heat of displacement
The heat change when one mole of a metal is displaced from its salt solution by a more electropositive metal
Heat of neutralisation
The heat change when one mole of water is formed from the reaction between an acid and an alkali
Phenolphthalein
Used to determine the end point of the titration
Proton number
Number of protons in the nucleus of an atom
Nucleon number
Total number of proton and neutron in an atom
Mole
Amount of substance that contain as many particle as the number of atoms is exactly 12g of carbon-12
Molecular formula
The chemical formula which shows the exact number of atoms in a molecule
Period
Horizontal row of elements in the Periodic Table of Elements
Anion
A negatively charged ion
Electrolysis
A process in which a compound js decomposed into its constituent elements by passing through an electric current through an electrolyte
Cathode
The electrode which is connected to the negative terminal of the dry cell
Alloy
An alloy is a mixture of two or more elements with a certain fixed composition in which the major components is a metal
Polymer
Large molecules made up of many identical repeating subunits of monomer
