C5.3/.4/.5/.6 - Extracting metals Flashcards
extracting metal depends on
-easiness of extraction from ore
-amount of metal ore contains
-changing demands for metal
metal + water observations of recation
-flame
-fizz
-hydrogen gas
-hydroxide made
how to check for hydrogen
lighted splint will make a pop sound if h2 is present
Reactivity series above carbon
-K
-Na
-calcium
-mg
-aluminium
Reactivity series above hydrogen
-zn
-fe
-tin
-pb
Reactivity series below hydrogen
-cu
-silver
-gold
-platinum
Reduction of oxide by carbon
- c will displace less reactive metal
- forming metal and co2
-chemical reduction occurs
-carbon = reducing agent
reducing agent
removes oxygen by being oxidised
Reduction of oxide by hydrogen
-more costly than C
-less common to use
-forms water and metal
when is hydrogen used as a reducing agent
-when carbon is likely to react with a metal to form a compound
-instead of the O2
electrolysis
used to extract metals more reactive than carbon
salt
compound formed when H2 in an acid is wholly/partially replaced by metal ions
Formula for metal + acid
metal + acid —> salt + hydrogen
all acids are
aqueous
how can a sample of salt be obtained after a reaction
crystallisation
metal + acid = redox reaction
-metal = loses electrons
-hydrogen = gains electrons
bases
compounds that neutralise acids
alkalis
soluble bases
eg of bases
metal oxides
Formula for neutralisation
acid + base —> salt + water
What ions do acids produce
-hydrogen ions
-H+
What ions do alkalis produce
-hydroxide ions
-OH-
H+ and OH- react to produce
water
Formula for acid + ammonia solution
acid + ammonia solution —> ammonium salt + water
Formula for acid + carbonate
acid + carbonate —> salt + water + co2
Formula for acid + hydroxide
acid + metal hydroxide —> salt + water
Formula for acid + metal oxide
acid + metal oxide —> salt + water
Formula for metal + oxygen
metal + oxygen —> metal oxide
pH
power of hydrogen
-refers to concentration of H+ ions
pH scale
-0 = acid
-7 = neutral
-14 = alkali
Litmus paper
-red in acid
-blue in alkali
higher concentration of H+ ions =
lower pH level
As concentration of H+ ions decrease by a factor of 10…
the pH value increases by 1 unit
Formula for dilution factor
final volume/initial volume
strong acid
dissociate fully in water to produce max number of H+ ion
weak acid
do not dissociate fully to form H+ ions
concentration of acids
moles of acids in a dm3 of solution
dilute solution
-fewer mols of acid
-more water particles
concentrated solution
-more mols of acid
-fewer water particles
concentrated weak acid
-many acid moles
-little dissociation of acid
concentrated strong acid
-many moles present
-lots of dissociation
dilute weak acid
-little acid
-little dissociation
dilute strong acid
-little acid present
- lots of dissociation
eg of strong acids
-HCl
-HNO3
-H2SO4
eg of weak acids
-ethanoic (vinegar)
-citric
-carbonic (rainwater/fizzy drinks)