Intro to chemistry

• Define an atom


  The smallest particle of matter made up of protons, neutrons and electrons
• Define element


  made up of only one sort of atom
• Define molecules


  Two or more atoms covalently bonded together. The atoms can be of the same element or different elements
• Define compounds 


  Two or more different types of atoms bonded together. Bonding can be either ionic or covalent
• Define mixture


  Two or more different elements and or compounds in the same space, they can be separated out
• formula of nitrogen 


  N2
• Formula of phosphorus 


  P4
• Formula of sulphuric acid

  H2SO4
• formula of nitric acid

  HNO3
• Formula of phosphoric acid

  H3PO4
• Transition metal ions


  They can form more than one stable ion. Roman numerals are used to identify the charge on the ion
• +1 ions


  ammonium, NH4+
• -1 ions


  Hydroxide: OH-

  Nitrate: NO3-

  Hydrogencarbonate: HCO3-
• -2 ions


  Carbonate: CO3 2-

  Sulfate: SO4 2-
• -3 ions


  Phosphate ion PO4 3-
• If more than one compound ion is present use brackets around the formula
• How to balance equations

  Metal

  Any other element (not CHO)

  Carbon

  Hydrogen

  Oxygen
• Combustion


  Burning a substance in oxygen

  methane + oxygen -> carbon dioxide + water
• Decomposition


  When a substance breaks down to form two or more substance. This may be thermal decomposition

  CaCO3 -> CaO + CO2
• Neutralisation


  An acid and base react to form water

  NaOH + HNO3 -> NaNO3 + H2O
• Redox


  Reduction and oxidation takes place

  Mg + 2HCL -> MgCl2 + H2
• Exothermic


  Releases heat energy to surroundings
• Endothermic


  takes heat energy in from surroundings
• Reversible reaction


  Reactants can form products and products can form products

  sulfur dioxide + oxygen —> sulfur trioxide
• What’s an acid?


  A substance that donates hydrogen ions.
• What’s a base?


  A base is a substance that can accept protons (h+ ions)
• What’s an alkali?


  A base that releases hydroxide ions in aqueous solution
• What’s a salt?


  It’s formed when the hydrogen ions from an acid are replaced by a metal or ammonium ion
• Chlorides are formed from

  HCL
• Sulfates are formed from

  H2SO4
• Nitrates are formed from

  HNO3
• Phosphates are formed from

  H3PO4
• Acid + alkali -> salt + water
• Acid + bass -> salt + water
• Acid + metal -> salt + hydrogen
• acid + metal carbonate -> salt +water + carbon dioxide
• Acid + metal hydrogencarbonate -> salt + water + carbon dioxide
• Acid + ammonia -> ammonium salt
• What happens when ionic substances dissolve in water?

  They separate into their positive and negative ions, they become hydrated so they interact with water molecules rather than each other
• Covalent compounds don’t contain ions so will not be altered in anyway in an ionic equation