2.1 Atoms and Reactions

• Isotopes

  atom of the same element with a different number of neutrons
• Relative Isotopic Mass

  mass of an isotope of an element relative to 1/12th of the mass of carbon 12
• Relative Atomic Mass

  average mass of atoms of an element relative to 1/12th of the mass of carbon 12
• One Mole

  amount of substance that contains as many particles as there are in exactly 12g of carbon 12
• Empirical Formula

  simplest ratio of atoms in an element in a compound
• Molecular Formula

  actual number of atoms of an element in a compound
• Anhydrous and Hydrated

  -Contains no water in the compound

  -contains water in the compound
• Water of Crystallisation

  refers to the water molecules which form an essential part of the crystalline structure of a hydrated salt
• percentage yield

  $actualmolesproduct/theoretical molesproduct *$$100$
• Benefits of high percentage yield

  -not wasting raw materials
• Atom Economy

  $Mr Desired Product/Sum Of Mr All Products *$$100$
• Benefits of high atom economy

  -one product means 100% atom economy

  -less waste product
• An Acid

  a proton donor
• Strong Acid

  fully dissociates in water
• Weak Acid

  partially dissociates in water
• Common Acids

  -HCl

  -H2SO4

  -HNO3

  -CH3COOH

  -H3PO4
• A Base

  proton acceptor
• An Alkali

  A soluble base forming hydroxide ions when dissolved in water
• Common Bases

  -Na2O

  -NaOH

  -NH3
• Common Alkali

  -NaOH

  -KOH

  -Ca(OH)2

  -NH3
• Salt

  a substance produced when the H+ ion of an acid is replaces by a metal ion or the ammonium ion.
• Ideal gas equation?


  PV = nRT
• pressure units?


  Pa and kPa to Pa *10^3
• Volume unit?

  m^3 and cm^3 to m^3 *10^-6
• R?


  8.314
• Temperature unit?


  K and 'c to K +273
• Oxidation

  loss of electrons (OIL)

  increase in oxidation number
• Reduction

  gain of electrons (RIG)

  decrease in oxidation number