chemical reactions

• metal +oxygen =

  metal oxide
• please stop lying cause my zebra is cool

  potassium ,sodium, lithium, calcium ,magnesium ,zinc , iron ,copper
• reactivity depends on ability to lose ... and become a + ion

  electrons
• three main acid

  hydrochloric acid hcl

  sulfuric h2so4

  nitric hno3
• in aqueous solutions acids produce .... ions

  hydrogen
• bases neutralise ...

  acids
• in aqueous solutions ,alkalis produce ..... ions

  hydroxide
• you can determine pH with pH ... or universal indicator

  probe
• neutralisation reaction 


  $H^+$$\ +$$\ OH^-\ =$$H_2O$
• metals more reactive than ....displace

  hydrogen
• acid +metal =salt +.....

  hydrogen
• acid+base=salt +....

  water
• salts contain + ion from base or ...

  salts contain - ion from ...

  alkali ,acid
• acid +metal carbonate =salt +.... +co2

  water
• strong acids fully ..... because arrow goes in direction

  ionise
• weak acids ... ionise

  partially
• ph scale

  -gives us an idea of conc of hydrogen ions

  -as pH decreases by 1 ,conc of hydrogen increase by 10
• the concentration of an acid tells us

  the volume of acid molecules
• titration

  -use pippette to transfer 25 cm of sodium hydroxide

  -add indicator like methyl

  -place on white tile

  fill burette with sulfuric acid

  -add acid to alkali

  -look at colour change and swirl

  -read at bottom of meniscus and eye level
• cm to dm = divide by 1000
• mol/dm3 to g/dm3 =times mr
• ionic compounds

  -cant conduct electricty when solid

  -when melted or disolved forces of attraction are broken and ions free to move
• negative electrode

  cathode
• reduction of aliminium oxide

  -melt aliminium oxide with cryolite to low mp

  -this reduces energy needed and saves money
• anything above carbon needs to reduced with ...

  electrolysis
• why does anode have to be replaced regularly

  oxygen produced reacts graphite to form co2 gas
• why is electrolysis expensive

  -lots of energy

  -lots of energy needed to start electric current
• electroylysis of aqueous solutions

  hydrogen is produced at the cathode is metal is more reactive than hydrogen but if less reactive than metal is produced
• electrolysis of aqueous solutions

  if halide ions than halogen produced or hydroxide