C4 Flashcards
metal carbonate + acid –> ______ +__________ + ______
salt + water + CO2
metal + acid –> _____+____
salt + hydrogen
acid + metal oxide —> ___+ ___
salt + water
what does oxidation mean?
the gain of oxygen
- the substance that gains oxygen has been oxidised
what does reduction mean?
the loss of oxygen
- the substance that lost oxygen has been reduced
PRACTICAL: making pure dry copper sulphate crystals
- measure 25cm^3 of sulfuric acid
- heat gently on bunsen burner, tripod, gauze and heat proof mat
- remove solution from bunsen burner and add copper oxide to acid with spatula and stir
- add excess copper oxide until no more will dissolve
- filter the mixture with filter paper, filter funnel and conical flask
- pour filtered solution into evaporating basin
- leave to dry in cool pace for 24 hours
- remove crystals from solution with a spatula
- gently pat crystals with filter paper
- you now have pure dry crystals of copper sulphate
what is oxidation in terms of electrons?
the loss of electrons
what is reduction in terms of electrons?
the gain of electrons
what is an ore?
a rock that contains a metal compound
what are bases?
chemicals that neutralise acids
what do bases produce?
a salt and water
what do acids produce in aqueous solutions?
hydrogen ions (H+ ion)
what are bases that are soluble in water also called?
alkalis
what do alkalis produce in aqueous solutions?
hydroxide ions (OH-)
which metals are extracted by heating with carbon?
metals less reactive than carbon
which metals are extracted by electrolysis?
metals more reactive than carbon
what 5 are signs a chemical reaction has taken place?
- fizzing
- colour change
- temperature change
- formation of a precipitate
- change in smell
what happens in displacement reaction?
a more reactive element will displace a less reactive element and form a compound
what ion do all salts have?
a positive ion
what is an acid?
a substance that releases H+ ions into solutions
what is an alkali?
a substance that release OH- ions into solutions
practical: why do you heat the acid gently first when making a salt?
to speed up the reaction
practical: why do you stir the solution after adding each spatula of metal oxide?
to make sure it’s fully neutralised