C5 Flashcards
The reactivity series
Potassium, Sodium, Calcium, Magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold, platinum
a more reactive metal can ____ a less reactive metal from a ___
displace, compound
The reactivity of metal is related to ____
tendency to form positive ions
more reactive metals form positive ions faster/slower
faster
reactions of metals with acids
metal + acid -> salt + hydrogen (MASH)
reactions of a metal with oxygen
metal + oxygen -> metal oxide
reactions of metal oxides with acids
metal oxide + acid -> salt + water
reactions of metal carbonates with acids
metal carbonate + acid -> salt + water + carbon dioxide
zinc + hydrochloride acid ->
zinc chloride + hydrogen
iron + oxygen ->
iron oxide
magnesium oxide + sulfuric acid ->
magnesium sulfate + water
tin carbonate + hydrochloric acid ->
tin chloride + water + carbon dioxide
what is oxidation?
when a metal forms a bond with a non metal and loses its outer shell electrons
what is reduction?
when a metal is in a compound and reacts to form an element, gaining electrons
what is this an example of: (oxidisation/reduction)
zinc + hydrochloric acid -> zinc chloride + hydrogen
oxidisation
what is this an example of: (oxidisation/reduction)
copper oxide + carbon -> copper + carbon dioxide
reduction
Metals can be split into three groups, based on how easy it is to extract them, which are:
- the most unreactive metals are found native in the Earth’s crust
- Metals less reactive than carbon can be extracted from compounds by reduction with carbon. this is a special example of a displacement reaction
(e.g. iron oxide + carbon -> iron + carbon dioxide) - metals more reactive than carbon may require electrolysis to extract them. this is expensive and requires a lot of energy
t/f? salts are ionic compounds
true
hydrochloric acid (symbol and what it reacts to make)
HCl, reacts to make chloride salts
sulfuric acid (symbol and what it reacts to make)
H2SO4, reacts to make sulfate salts
nitrate acid (symbol and what it reacts to make)
HNO3, reacts to make nitrate salts
iron + hydrochloric acid ->
iron chloride + hydrogen
zinc + sulfuric acid ->
zinc sulfate + hydrogen
magnesium + nitric acid ->
magnesium nitrate + hydrogen
how can soluble salts be made?
from acids by reacting them with solid insoluble substances, such as metals, metal oxides, hydroxides or carbonates
describe the method for the “making a names soluble salt” RP:
- the ____ is added to the acid until no more _____
- The ______ is filtered off to produce a solution of the salt
- the salt solution is ____ and then left to _____ to produce solid salt.
- An excess of the solid MUST be added to _____
- solid metal compound
- reacts
- excess solid
- heated
- crystallise
- make sure no acid remains to form an impurity in the salt product
what apparatus is required for a titration
a pipette to accurately measure the volume of a reactant before transferring it to a conical flask
a burette to add small, measured volumes of one reactant to the other reactant
titration method:
- Use the pipette and pipette filler to add a measured volume of sodium hydroxide solution to a clean conical flask.
- Add a few drops of indicator and put the conical flask on a white tile.
- Fill the burette with hydrochloric acid and note the starting volume.
- Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
- Stop adding the acid when the end-point is reached (when the indicator first permanently changes colour). Note the final volume reading.
- Repeat steps 1 to 5 until
concordant titres are obtained. More accurate results are obtained if acid is added drop by drop near to the end-point
cm^3 -> dm^3 =??
DIVIDE by 1000
number of mols=
concentration x volume
colour change for methyl orange:
yellow- red
colour change for phenolphthalein:
colourless- pink
What is an alkali
A base which is soluble in water
Strong acids-
Hydrochloric acid, sulfuric acid, nitrate acid– They fully ionise to release H+ ions extremely easily
Weak acids-
Ethanoic acid, citric acid, carbonic acid- only partially ionise in aqueous solution, meaning some molecules split up
Acidic solutions contain
Hydrogen, H+
Alkalines contain-
Hydroxide, OH-
Hydrochloric acid
HCl
Sulfuric acid
H2SO4
Nitric acid
HNO3
pH 1 has a ___ greater concentration of H+ than pH2
10x
pH 1 has a ____ greater concentration of H+ than pH3
100x
Neutralisation
Occurs between an acid and base
Alkalis are bases which
Are soluble in water- many bases aren’t soluble in water
Neutralisation reactions produce:
A salt and water
Acids release what when they are dissolved in water?
H+ ions
Calculating concentration of unknown acid from titration-
A. Calculate mean titre volume - from concordant results only
B. Calculate mols of alkali used, then divide by mean vol
Acidic solutions contain-
Hydrogen ions
Alkali solutions contain
Hydroxide [OH-]
Strong acids do what in water?
Fully ionise
Strong acids can be concentrated or dilute, which depends on…
Amount of acid dissolved in 1cm3 of water
Weak acids will have a higher pH (so less acidic) than a strong acid of the same…
Concentration
Half equations are to show what happens to each what in terms of what?
Reactant,, electrons
Fe(s) –>
Fe2+(aq) + 2e-
- iron loses 2 electrons to form an iron ion- it’s oxidised
Cu2+(aq) + 2e- –>
Cu(s)
Copper ions gains 2 electrons to form a Cu atom– its reduced
