Chem

• Element


  Pure substance composed of similar atoms having same atomic number & same chemical behavior
• Atom


  Smallest part of an element that enters a reaction
• Atomic Number


  Number of protons
• Mass (Nucleon) Number


  Total number of protons and neutrons
• Isotopes


  Atoms of the same element having same number of protons but different number of neutrons (same atomic number but different mass number)
• Catalyst


  A substance that speeds up the reaction without being used up (chemically changed)
• Ion


  Charged atom by losing or gaining electrons
• Compound


  A substance containing different atoms or ions chemically bonded together
• Simple lattice


  A regular arrangement of alternating opposite charged ions
• Molecule


  Smallest group of atoms covalently bonded
• Diatomic


  2 atoms bonded together
• Volatile


  Low boiling point
• Sublimation


  A process in which the solid material changes by heating directly from the solid state to the gaseous state without passing through the liquid state
• Mixture


  Different substances together without bonding (can be separated)
• Alloy


  A mixture of metals
• Acid


  Proton donor
• Base


  Proton acceptor
• Alkali


  A soluble base
• Effervescence


  Bubbles of gas
• Exothermic


  Reaction which gives out heat
• Endothermic


  Reaction which takes in heat
• Redox Reaction


  A reaction that involves simultaneous oxidation and reduction
• Oxidation


  Gain of oxygen. Loss of electrons
• Reduction


  Loss of oxygen. Gain of electrons
• Oxidizing agent


  A substance that oxidizes another substance and is itself reduced
• Reducing agent


  Substance that reduces another substance and is itself oxidized
• Diffusion


  The random movement of molecules (particles) from high concentration to low concentration
• Relative atomic mass (Ar)


  Average mass of naturally occurring atoms of an element relative to 12C
• Relative molecular mass (Mr)


  Sum of the relative atomic masses
• Saturated solution


  A solution having the maximum concentration of a solute dissolved in the solvent at a specified temperature
• Electrolysis


  Breaking down of a compound by electricity
• Mole


  Chemical unit expressing the amount of substance in grams or dm3
• Avogadro's rule


  One mole of any substance contains 6.02 x 10^23 particles (Avogadro's constant)
• Empirical formula


  The simplest whole number ratio of the different atoms or ions in a compound
• Molecular formula


  The actual number of atoms in one molecule
• Thermal decomposition


  Breaking down of a compound by heat
• Water of Crystallization


  Water molecules present in hydrated crystals
• Pollution


  The presence of any harmful substance in the environment
• Enzyme


  A biological catalyst
• Activation Energy


  The minimum energy that colliding particles must have to react