C5 Flashcards
what are 2 uses of carbon
displaces less reactive metals from their oxides
used to extract some metals from their ores in industry
what is a metal ore
a rock that contains enough metal/ metal compound to make it worth extracting the metal
how are metals more reactive than carbon extracted
by electrolysis and metals less reactive are reduced by carbon
why would you reduce a metal (remove oxygen)
to extract the metal from its oxide
what is the displacement reaction of magnesium + copper
magnesium is more reactive so copper ions will be displaced from the solution to form copper metal. the magnesium forms aqueous magnesium ions and dissolved into the solution
why is hydrogen positioned between copper and lead in the periodic table
because copper can’t displace the hydrogen from an acid but lead can
when is a salt formed
when the hydrogen in an acid is partially or wholly replaced by metal or ammonium ions
what has to be for reactions between metals and acids to occur
the metal has to be more reactive than the hydrogen in the acid
what happens when acid dissolves in water
H+ ions are released
why are alkali metals never added to acid
because the reaction would be too violent
what is a radox reaction
when the metal atoms lose electrons and are oxidised and the hydrogen ions from the acid gain electrons and are reduced
what happens when an acid and a base react
a neutralisation reaction occurs and a salt and water are produced
what is the difference between alkalis and bases
ashes are compounds that neutralise acids and alkalis are bases that are soluble in water
what are salts made up of
positive metal ions or ammonium ions and a negative ions from an acid so they have no overall charge
how can a pure dry sample of the salt made in an acid base reaction be crystallised
by evaporation it from the solution and drying it with filter paper
what are the 2 reactions used to make salts
solutions of an acid + alkali
acid + carbonate
how do you make pure dry samples of crystals
1) carry out titration to see how much acid reacts completely with the alkali
2) run that volume of acid into the alkali solution again but without indicator
3) crystallise and dry the crystals of salt from the reaction mixture
what is ethanoic acid in
vinegar
what is citric acid in
citrus fruit and fizzy drinks
what pH is acidic and which is alkaline
1-6 is acidic
8-14 is alkaline
7is neutral
what is different about the CO2 release when a metal carbonate reacts with a carboxylic acid compared to hydrochloric acid of the same concentration
the release of CO2 is slower when a metal carbonate reacts with a carboxylic acid because even though they are the same concentration, HCL is a stronger acid and carboxylic acid is weak
why must acid dissolve in water before showing acidic properties
because is water acids ionise (split up). their molecules split to form H+ (aq) ions and negative ions
what is the difference between strong and weak acids when they dissolve in water
strong acids ionise completely but in weak acids most molecules stay as they are
what happens to they hydrogen ion concentration of the solution when the pH decreases by 1 unit
the hydrogen ion concentration of the solution increases by a factor of 10
