Chemistry

• Reactivity

  How vigorously a substance chemically reacts
• Ordering metals by reactivity

  1. Comparing their reactions with water

  2. Comparing their reactions with other substances
• Reactivity series

  A list of metals ordered by their activity
• Reactivity of metals

  Determined by how easily they lose their outer shell electrons
• Gold and silver are found naturally as elements in the Earth's crust because they are very unreactive
• Ion

  An atom or molecule with a net electric charge
• Extracting less reactive metals from their ores


  Reduction with carbon
• Oxidation


  Addition of oxygen
• Reduction


  Removal of oxygen
• Metals like potassium and aluminium cannot be extracted by reduction with carbon because they are more reactive than carbon
• Extracting more reactive metals from their ores


  Electrolysis
• Displacement reaction


  A more reactive substance takes the place of a less reactive substance in a compound
• Ionic equation


  An equation which gives some substances as ions and has spectator ions removed
• Spectator ion

  An ion that is unchanged in a reaction
• Half equation


  An equation that shows whether a substance is losing or gaining electrons
• Oxidation


  Loss of electrons
• Reduction


  Gain of electrons
• The actual yield is always less than the theoretical yield due to factors like reaction reversibility, product loss, and unexpected side reactions
• Metals are located to the left and non-metals to the right on the Periodic Table
• Mendeleev swapped the order of some elements to group them by their chemical properties
• Titration


  A method used to calculate the concentration of an unknown solution
• Formula to calculate mass from moles and molar mass


  Mass = moles x molar mass
• Theoretical yield


  The maximum mass of the product that could have been produced
• Ionic substances conduct electricity when melted or dissolved because the ions are free to move and carry charge
• Small numbers of atoms group together into molecules with strong covalent bonds between the atoms and weak intermolecular forces between the molecules
• A solution with a pH of 7 is neutral (neither acidic nor basic).
• Acids have a pH less than 7, while bases have a pH greater than 7.
• Acids react with metals to produce hydrogen gas.
• Bases react with acids to form salts and water.
• Stronger bases will be more reactive than weaker ones, so they can remove H+ ions from stronger acids as well as weaker ones.
• Strong acids completely ionize in water, while weak acids only partially ionize.
• Stronger acids release more H+ ions per unit volume compared to weaker acids.
• Weak acids only partially ionize in water, releasing some H+ ions but not all.
• Metals react vigorously with oxygen gas to produce metal oxides, which may be soluble or insoluble depending on their properties.
• The pH scale measures how acidic or alkaline a substance is on a logarithmic scale from 0-14.
• Stronger acids have lower pH values, indicating higher acidity.
• The reaction between an acid and a base produces salt and water.
• An ionic compound contains metal and non-metal elements that are held together by electrostatic attraction.
• Ionic compounds dissolve in water to give solutions containing positive and negative ions called electrolytes.
• The concentration of the hydronium ion in an acidic solution determines its strength.