SPM Chemistry Definition List

SPM Chemistry Form 4 Defnition List: 1. Element  – a substance consists of one type of atom. 2. Compound  – a substance consists two or more elements that are chemically bonded(molecule bonded(molecule or ions). ions). 3. Atom – smallest particle of an element. 4. Molecule  – a group of two or more atoms. 5. Ion – a positively charged  negatively ne gatively charged particle. !. Isotopes – atoms of the same element with same proton number but di"erent nucleonnumbers. #. Relatie atomic mass o! an element  $ the average mass of one atom of an element((112) % the mass of one carbon&12 atom) '. Relatie molecular mass o! an element  $ the average mass of one atom of an molecule((112) % the mass of one carbon&12 atom) . Molecule !ormula  – compound shows the actual number of atoms of each element that are present in a molecule of the compound 1. Empirical !ormula  – compound shows the simplest whole number ratio of  atoms of each element in the compound 11. Mole – amount of substance that contains as many m any particles as the number of atoms ine%actly 12 g of carbon&12 the symbol of mole is mol. 12. "ne mole – *vogadro constant – !.2 % 1 23 13. #roup (Periodic Table) Table) – vertical columns of element (similar chemical properties). 14. Periods (Periodic Table) Table) – hori+ontal rows of element. 15. $alence electrons – electrons that occupy the outermost shell. 1!. Ionic %ond – bond formed through the transfer of electrons between atoms of metal andnon&metal to achieve the stable octet electron arrangement. 1#. Ionic compound  – consist of positive ions and negative ions which are held by strong electrostatic forces of attraction. 1'. Coalent %ond  – bond formed through the sharing of non&metal electrons to achieve the stable duplet or octet electron arrangement. 1. Coalent compound  (also simple molecular structure) – consists of neutral molecules which are held by wea, intermolecular forces (Van (Van der Waals). Waals). 2. Al&ali  (base) – chemical substance which ioni+es in i n water to produce & hydro%ide hydro%ide ions- / . 21. Acid – chemical substance which ioni+es in water to produce hydrogen ions- /0 or hydro%onium ions- / 30.

22. p' – degree of acidity or al,alinity of a solution. cale ranges from  to 14. 23. p' alue – measure of the concentration of hydrogen ions- /0. 24. Stron( al&ali – ionises (dissociates) completely in water to form hydro%ide ions- /& of high concentration. 25. )ea& al&ali  – ionises (dissociates) partially in water to form hydro%ide ions- /& of low concentration. 2!. Stron( acid – ionises (dissociates) completely in water to form hydrogen ions- /0 of high concentration. 2#. )ea& acid – ionises (dissociates) partially in water to form hydrogen ions/0 of low concentration. 2'. Polymer – long chain molecules made up by monomer (repeating unit).

SPM Chemistry Form * Defnition List: 1. E+ectie collision  (Collision theory ) – collision that results in a chemical reaction where the particles collide with the correct orientation and are able to achieve the activation energy. 2. 'omolo(ous series  – organic compounds (families) with similar formulae and properties. 3. Catalyst  – a chemical that alter the rate of reaction. 4. Positie catalyst  – increases the rate of reaction  lower the activation energy. 5. ,e(atie catalyst  – decreases the rate of reaction  higher the activation energy !. "r(anic compounds – carbon&containing compound. arbon atoms form covalent bonds. #. Inor(anic compounds  – compounds from non&living things which do not contain the element carbon. '. Saturated hydrocar%ons – hydrocarbons containing only single bonds between all carbon atoms. . -nsaturated hydrocar%ons  – hydrocarbons containing at least one carbon&carbon doubleor triple bond. 1. Esterifcation – esters are produced 11. $ulcanisation – process which ma,es the natural rubber harder and increases its elasticity by adding sulphur. 12. Redo. reaction – chemical reactions involving o%idation and reduction occurring simultaneously. 13. Flaourin( – improve the taste or smell of food and restore taste loss due to food processing.

14. Sta%ilisers – help to mi% two liuids that usually do not mi% together so that they form an emulsion. 15. /hic&eners – substances that thic,en food and give the food a rmsmooth and uniform te%ture. 1!. Precipitation – the heat change when one mole of a precipitate is formed from their ions in aueous solution. 1#. Displacement – the heat change when one mole of a metal is displaced from its salt solution by a more electropositive metal. 1'. ,eutralisation – the heat change when one mole of water is formed from the reaction between an acid and an al,ali. 1. Com%ustion – the heat change when one mole of a substance is completely burnt in o%ygen under standard conditions.