Chemistry - chemical changes (C4a)

• C4a - chemical changes

  what is an acid

  acids release H+ ions in aqueous solutions (dissolved in water) and neutralise bases
• what is a base

  a substance that neutralises an acid (can accept H+ ions)
• what is an alkali

  a soluble hydroxide that release OH- ions in aqueous solutions
• does a strong acid have more or less H+ ions than a weak acid?

  a strong acid has more H+ ions than a weak acid

  
• does a strong base have more or less OH- ions than a weak base?

  a strong base has more OH- ions than a weak base
• what does high concentration mean

  a high number of acid particles per unit volume
• what does dilute mean?

  adding more water so more H20 particles than other particles (e.g acid)
• what do strong acids do to their H+ ions?

  strong acids can fully ionise its H+ ions
• what is the equation for the reaction between an acid and a base

  acid + base(alkali) -> salt + water
• what is the equation for metal + acid

  metal (base) + acid -> salt + hydrogen

  example - lithium + sulfuric acid -> lithium sulfate + hydrogen
• what is the equation for metal oxide + acid

  metal oxide + acid -> salt + water

  example - calcium oxide + sulfuric acid -> calcium sulphate + water
• what is the equation for metal hydroxide + acid

  metal hydroxide + acid -> salt + water

  example calcium hydroxide + sulfuric acid -> calcium sulphate + water
• what is the equation for metal carbonate + acid

  metal carbonate + acid -> salt + water + carbon dioxide
• what is the equation for ammonia + acid

  ammonia + acid -> ammonium salt

  ammonia + sulfuric acid -> ammonium sulfate
• the reactivity series

  most reactive

  potassium

  sodium

  lithium

  calcium

  magnesium

  carbon

  zinc

  iron

  lead

  hydrogen

  copper

  silver

  gold

  least reactive

  
• what is the equation for metal + oxygen

  metal + oxygen -> metal oxide

  example magnesium + oxygen -> magnesium oxide
• what is the equation for metal + water

  metal + water -> metal hydroxide + hydrogen

  example magnesium + water -> magnesium hydroxide + hydrogen
• what is the reaction of the metal potassium reaction with water

  very violent
• reaction of metal sodium with water

  sodium is very quick
• reaction of metal lithium with water

  lithium is quick
• reaction of the metal calcium with water

  calcium is more slow
• reaction of the magnesium with water

  magnesium reacts relatively slowly
• reaction of zinc with water

  zinc is fairly slow/ little to no reaction
• reaction of iron with water

  iron is more slow/ little to no reaction
• reaction of copper with water

  reaction of copper is very very slow almost unreactive
• describe displacement reactions

  a more reactive metal can displace a less reactive metals from a compound
• balancing symbol equations

  Na + O2 -> Na2O

  Na 1+ O2-

  Na 2 O - the ions of each molecule switch places
• state symbols what is the state symbol of liquid, solids, gases and aqueous solutions

  solid - s

  liquid - l

  gases - g

  aqueous - aq