Which technique is the best for separating pure water from a solution of sodium chloride in water?
Chromatography
Crystallisation
Distillation
Filtration
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Which technique is the best for separating pure water from a solution of sodium chloride in water?
Chromatography
Crystallisation
Distillation
Filtration
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Which of the following is not a pure substance?
Seawater
Calcium carbonate
Distilled water
Ammonia
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A student was investigating the colours in black food colouring.
Chromatography was carried out on samples A-E and compared to the black food colouring.
The following chromatogram was produced.
Which of the following conclusions is not true for this chromatogram?
Sample B is insoluble in the solvent used
Samples C and D are pure substances
Sample D is the least soluble of the samples
The black ink is a mixture of A, E and an unknown
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A company produces tin from an ore called cassiterite, which is mainly tin oxide.
What is the relative formula mass (Mr) of tin oxide, SnO2?
Relative atomic masses (Ar): Sn= 119 O= 16
135
151
270
1904
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The diagram shows the displayed formula of succinic acid.
What is the empirical formula for this compound?
C4H6O4
CH2O
C2H3O2
CHO
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A student set up the following apparatus to investigate the colours in three different food colourings.
What are the stationary and mobile phases for this experiment?
Stationary | Mobile | |
A | chromatography paper | water |
B | beaker | start line |
C | water | food colourings |
D | start line | chromatography paper |
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A student making copper sulfate crystals used the method below.
Unreacted copper carbonate was left over as it had been added in excess.
Which separation technique could be used to separate the unreacted copper carbonate and solution into different containers?
Filtration
Crystallisation
Simple distillation
Fractional distillation
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A mixture contains methanol and ethanol. They have different boiling points.
Which method could be used to separate this mixture?
Filtration
Simple distillation
Crystallisation
Evaporation
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A student carried out chromatography on a sample of green ink.
The distance moved by the solvent front is 5.8 cm.
The distance moved by the yellow dye is 4.5 cm.
Calculate the Rf value of the yellow dye to 2 significant figures.
0.78
0.80
1.3
26
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The diagram below shows a heating curve for a pure substance.
Which part of the curve shows a change of state happening?
A to B
B to C
C to D
B to D
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The gas chromatogram shows the different substances in a gas mixture.
Which statement below is not true?
The mixture contains six substances
Substance A has the shortest retention time
The relative amounts of substance D and E are very similar
Substance F has the greatest affinity for the mobile phase
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