C3.3 Flashcards
describe what you saw happen during the PAG when you add the copper oxide to the warm acid
the copper oxide dissolved in the colourless acid and made the solution a deep blue, the powder stopped dissolving and the solution became saturated.
what is the purpose of filtration, crystalisation and leaving the saturated solution to cool and crystalise slowly in the PAG?
The purpose of filtration is to filter out the insoluble solid so that we were just left with the solution. The purpose of crystallisation is to evaporate off the water until saturated to form salt crystals. The purpose of leaving the crystals to cool slowly is so that the crystals can form easier.
in the PAG what was the filtrate and what was the residue?
The filtrate was the solution that ended up in the conical flask which was a copper sulfate solution. The residue was the remaining copper oxide left in the filter paper.
suggest reasons why some of the salt made did not make to the final product in the PAG
Some of the salt was left behind on the filter paper and transfer errors.
predict the properties of the product in the PAG
-high melting and boiling points
-does not conduct electricity
-hard, brittle
what is an alkali?
have the same properties of a base but dissolves in water
is hydroxide an acid or an alkali?
alkali
what do all acids release in water?
hydrogen ions (H+)
what does pH stand for?
potential hydrogen
what do all alkalis release in water?
hydroxide ions (OH-)
what is the ionic equation of neutralisation?
H+ (aq) + OH- (aq) –> H2O (l)
hydrochloric acid
HCl
nitric acid
HNO3
phosphoric acid
H3PO4
sulfuric acid
H2SO4
acid + metal –>
salt + hydrogen
acid + metal hydroxide –>
salt + water
acid + metal oxide –>
salt + water
acid + metal carbonate –>
salt + water + carbon dioxide
dilute
less particles in a given volume
concentrated
more particles in a given volume
strong acid
fully ionises in water- all their molecules release H+ ions
week acid
partially ionises in water- only a small fraction of their molecules release H+ ions
properties of acids
-taste sour
-have a pH less than 7
-corrosive
-turns blue litmus paper red
properties of bases
-taste bitter
-have a pH greater than 7
-corrosive
-turns red litmus paper blue
what is the word equation for the PAG- making a soluble salt?
copper (II) oxide + sulfuric acid –> copper sulfate + water
how do you calculate the hydrogen ion concentration with pH?
10^-pH
-if the pH decreases by 1 the H+ concentration increase by a factor of 10
titration curve
shows the effect on pH during a neutralisation reaction due to changing hydrogen concentration
