FORM 4
CHEMISTRY DEFINITIONS
FATEEN & SYARAH
CHAPTER 1: INTRODUCTION TO CHEMISTRY
Chemistry: A field of science that studies the structures, properties, compositions and interactions between matter.
Matter: Something that has mass and occupies space.
CHAPTER 2: MATTER AND THE ATOMIC STRUCTURES
Plasma: The fourth state of matter besides solid, liquid and gas. (An ionised gas).
Melting point: The constant temperature when a substance changes from solid state to become liquid at a specific pressure.
Freezing point: The constant temperature when a substance changes from liquid state to become solid at a specific pressure.
Atom: The smallest spherical body that cannot be created, destroyed nor divided further.
Proton number: The number of protons in the nucleus of an atom.
Nucleon number: The total number of protons and neutrons in the nucleus of an atom.
Valence shell: The outermost shell of an atom.
Isotopes: Atoms of the same element with the same number of protons but different number of neutrons.
CHAPTER 3: THE MOLE CONCEPT, CHEMICAL FORMULA AND EQUATION
Relative atomic mass, RAM: The average mass of an atom of the element compared to 1/12 of the mass of one carbon-12 atom.
Relative formula mass, RFM: The relative mass of an ionic substance.
Mole: The SI unit of amount of substance.
One mole of substance: A substance containing 6.02 × 10^23 mol-1 elementary entitles of a substance.
Molar mass: The mass of one mole of substance.
Molar volume: The volume occupied by 1 mole of a gas.
Chemical formula: A representation of a chemical substance using alphabets to represent atoms and subscript numbers.
Elements: Substances that consist of only one type of atoms.
Empirical formula: The chemical formula that shows the simplest ratio of the number of atoms of each element in a compound.
Molecular formula: The chemical formula that shows the actual number of the number of atoms of each element in a compound.
FATEEN & SYARAH
CHAPTER 4: THE PERIODIC TABLE OF ELEMENTS
Periodic Table of Elements: A form of systematic classification of elements in ascending order of proton numbers from left to right and from top to bottom.
Groups (Valence electron): Vertical columns in the Periodic Table of Elements.
Periods (Number of shells): The horizontal rows in the Periodic Table of Elements.
Semi-metallic Elements/ Metalloid: Elements that have both the properties of metal and non-metal.
Transition elements: Metals with high melting point and boiling point, hard, shiny surfaces, malleable and ductile.
Noble/ Inert gases: Gases that are chemically unreactive due to valence shells that are fully filled with electrons.
CHAPTER 5: CHEMICAL BOND
Chemical bonds: Bonds that are formed when electron transfer or electron sharing takes place.
Ionic bond (Electrostatic attraction forces): Bond that is formed by the transfer of electrons between metal atom and a non-metal atom.
Ionic compound: Compound that is formed when ions of opposite charges attract one another to form ionic bond.
Covalent bonds: Bonds that are formed when a non-metal atoms share their electrons to achieve a stable duplet or octet arrangement. (Between non-metal atoms)
Hydrogen bonds: Attraction forces between hydrogen atom, H that has bonded with an atom of high electronegativity. (Nitrogen, N) (Oxygen, O) (Fluorine, F)
Dative bond/ Coordinate bond: A type of covalent bond where the electron pair that is shared comes from one atom only.
Metallic bond: Electrostatic attraction force between the sea of electrons and the positive-charged metal ions.
Delocalised electron: Electron that moves freely and is not owned by any atom nor ion.
Water: A polar solvent that has partial negative charge at the oxygen atom and partial positive charge at the hydrogen atom.
Lattice structure: The orderly arrangement of atoms, ion or molecules of a compound in a solid crystal.
FATEEN & SYARAH
CHAPTER 6: ACID, BASE AND SALT
Acids: Chemical substances that ionise in water to produce hydrogen ions, H+.
Base: A substance that reacts with acid to produce salt and water only.
Alkali (Base that is soluble in water): Chemical substances that ionise in water to produce hydroxide ions, OH-
Strong acid: An acid that ionises completely in water to produce a high concentration of hydrogen ions, H+.
pH: A logarithmic measure of the concentration of hydrogen ions in an aqueous solution.
Basicity of acids: The number of hydrogen ions, H+ that can be produced by an acid molecule that ionises in water.
Weak acid: An acid that ionises partially in water to produce a low concentration of hydrogen ions, H+.
Strong alkali: An alkali that ionises completely in water to produce a high concentration of hydroxide ions, OH-.
Weak alkali: An alkali that ionises partially in water to produce a low concentration of hydroxide ions, OH-.
Concentration of a solution: A measurement that shows the quantity of solute dissolved in a unit volume of solution, normally in 1 dm3 solution.
Concentration in unit g dm-3: The mass of solute found in 1 dm3 solution.
Concentration in unit mol dm-3/ Molarity: The number of moles of solute found in 1 dm3 solution.
Standard solution: A solution with known concentration.
Neutralisation: A reaction between an acid and an alkali (base) to produce salt and water only.
Titration: A quantitative analysis method to determine the volume of acid needed to completely neutralise a given volume of alkali and vice versa.
Salt: An ionic compound formed when the hydrogen ion, H+ from the acid is replaced with the metal ion or the ammonium ion, NH4+.
Soluble salts: Salts that dissolve in water at room temperature.
Insoluble salts: Salts that don't dissolve in water at room temperature
Continuous variation method: A method used to construct the ionic equation for the formation of insoluble salts.
Qualitative analysis of a salt: A technique used to identify the cation and anion present in a salt by analysing its physical and chemical properties.
FATEEN & SYARAH
CHAPTER 7: RATE OF REACTION
Rate of reaction: The changes in the quantity of the reactant per unit time or the changes in the quantity of product per unit time.
The average rate of reaction: The average value for the rate of reaction that occurs in a particular time interval.
The instantaneous rate of reaction: The rate of reaction at a particular point of time.
Catalyst: Chemical substances that alter the rate of reactions without undergoing any chemical changes at the end of the reaction.
Ineffective collision: Collision between particles with energy less than the activation energy or in the wrong orientation.
Effective collision: Collision between particles with energy equal to or more than the activation energy and collide in the correct orientation.
Catalyst: Provides an alternative pathway by lowering activation energy .
Exothermic reactions: Reactions that release heat energy to the surroundings
Endothermic reactions: Reactions that absorb heat energy from the surroundings
CHAPTER 8: MANIFACTURED SUBSTANCES IN INDUSTRY
Alloy: A mixture of two or more elements where the main element is a metal.
Ceramic: A solid made up of inorganic and non-metallic substances.
Composite material: A material made from combining two or more non-homogeneous substances, that is matrix substance and strengthening substance.
FATEEN & SYARAH
FORM 5
CHEMISTRY DEFINITIONS
FATEEN & SYARAH
CHAPTER 1 : REDOX EQUILIBRIUM
Redox Reaction: A chemical reaction where oxidation and reduction occur simultaneously
Oxidation : Gains O2, loses hydrogen and electron
Reduction : loses O2, gains hydrogen and electron
Oxidation number : The charge of elements in a compound if the transfer of electrons occurs in an atom to form chemical bonds with other atoms.
Electrode potential : The potential difference produced when an equilibrium is established between metal M and the aqueous solution containing metal Mn+ ions in half-cell
Electrolytes : substance that conduct electricity in either the molten state or aqueous solution and undergo chemical changes.
Electrolysis : process whereby compounds in the molten state or an aqueous solution decompose into their constituent elements by passing electricity through them.
Corrosion of metal : redox reaction where the metal is oxidised spontaneously when the metal atoms release electrons to form metal ions.
CHAPTER 2 : CARBON COMPOUND
Carbon compound : compounds that contain carbon as their constituent element.
Hydrocarbon : Organic compounds containing only hydrogen and carbon.
Non- Hydrocarbon : Organic compounds containing carbon and hydrogen and other elements such as oxygen, nitrogen, phosphorus or halogens.
Saturated Hydrocarbon : Hydrocarbons containing only single bonds between carbon atoms.
Unsaturated Hydrocarbon : Hydrocarbons containing at least one double bond or triple bond between carbon atoms.
Fractional Distillation : The fractions of hydrocarbon in petroleum are separated at different temperatures according to the size of the hydrocarbons.
Cracking : Long chain of hydrocarbons are cracked into smaller molecules at a high temperature using a catalyst.
Isomers : Molecules that have the same molecular formula but different structural formulae.
FATEEN & SYARAH
CHAPTER 5 : CONSUMER AND INDUSTRIAL CHEMISTRY
Oils and fats : Esters produced through the reaction between fatty acids and glycerol (propan-1,2,3-triol).
Soap : Sodium or potassium fatty acid salts. @ Are produced from the neutralisation reaction between fatty acids and alkalis.
Detergents : Non-soap cleaning agents. @ Sodium salts of sulphonic acids.
Saponification : Process of hydrolysis of oils or fats by alkalis.
Hard water : Water containing calcium ions, Ca2+ and magnesium ions, Mg2+
Scum : Soap anions combine with the cations to form insoluble salts
Food Additives : Natural or synthetic ingredients added to food to prevent damage or to improve the appearance, taste or texture.
Medicine : Chemicals used to help with the treatment or prevention of diseases.
Cosmetics : Materials are materials or products that are used externally to cleanse, protect or enhance one's appearances.
Nanoscience : Study on processing of substances at nanoscale that are between 1 nanometre to 100 nanometres.
Nanotechnology : Development of substances or gadgets using the properties of nanoparticles.
Green Technology : Technology or application developed to minimise the negative effectsof harmful human activities.
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