numero dos

• when metals react with oxygen we get a metal oxide'
• what do we get when a metal reacts with oxygen

  metal oxide
• what do we call a reaction when oxygen is lost

  a reduction reaction
• where are unreactive metals found

  in the earth as the pure metal itself
• a more reactive element will displace a less reactive one
• oxidation is ---- of electrons

  loss
• reduction is ---- of electrons

  gain
• what do acids produce in aqueous solutions

  H+ / hydrogen ions
• in aqueous solutions acids produce..

  H+ ions
• bases are chemicals that can neutralise acids and produce a salt and water
• bases are usually

  metal oxides or metal hydroxides
• bases that are soluble in water are called

  alkalis
• what happens when a base neutralises an acid

  it produces salt and water
• in an queous solution alkalis produce

  OH- ions
• what produce OH- ions in an aqueous solution

  alkalis
• acids have a pH between 0-6
• alkalis have a pH of 8-14
• all acid contain hydrogen
• acids and metals make a salt and hydrogen
• acids and metals make ...

  salt and hydrogen
• why do acids and metals make salts and hydrogen

  because if the metals is more reactive than hydrogen then it will displace it from its compound
• hydrochloric acid makes

  chloride salts
• sulfuric acid makes salts ending in

  sulfate
• the faster the reaction ... the easier it is for the metal to form an ion
• why does magnesium reacts fast with acid

  it forms ions quicker
• acid + base ---> salt + water
• salts contain ...

  a positive ion from the base or alkali and a negative ion from the acid
• metal carbonates also react with acids to neutralise them
• acid + metal carbonate ---> salt + water + carbon dioxide
• what is the term for what acids do when they split and release H+ ions

  ionisation
• do strong acids fully ionise or not

  they fully ionise in aqueous solutions
• what do weak acids do

  partially ionise
• weak acids partially ionise
• three weak acids include

  carbonic , ethanoic , citric
• the pH scale gives us an idea of concentration of 


  hydrogen ions
• stronger acids have a lower pH than weak acids for given concentration
• when the ph scale decreases by one unit - the concentration of hydrogen ions increases by 10 units
• solid ionic compounds cant conduct electricity
• an electrolyte is

  a liquid or solution that can conduct electricity
• why do we mix some compounds with cryolite before electrolysis

  to lower the melting point and save energy and money