Experimental Techniques and Chemical Analysis
215 questions· page 1 of 22
A titration is completed.
of aqueous sodium hydroxide is added to a conical flask.
A few drops of methyl orange indicator are added.
Dilute hydrochloric acid is added slowly to the mixture until the colour changes.
Which row is correct?
Options
| apparatus used to add alkali | apparatus used to add acid | colour change of indicator | |
|---|---|---|---|
| A | volumetric pipette | burette | red to orange |
| B | measuring cylinder | burette | red to orange |
| C | volumetric pipette | burette | yellow to orange |
| D | volumetric pipette | measuring cylinder | yellow to orange |
An impure sample of compound X has a melting point of .
X is purified and its melting point is measured again.
Which row is correct?
Options
| method of purifying X | melting point of pure X / | |
|---|---|---|
| A | crystallisation | 125 |
| B | crystallisation | 115 |
| C | distillation | 125 |
| D | distillation | 115 |
Samples of two compounds, P and Q, are tested. The result of each test is shown.
| test | P | Q |
|---|---|---|
| add dilute hydrochloric acid | gas given off that turns limewater milky | no observable change |
| acidify with dilute nitric acid then add aqueous barium nitrate | no precipitate forms | white precipitate |
| add aqueous sodium hydroxide | no observable change | green precipitate, soluble in excess |
| add aqueous ammonia | no observable change | green precipitate, insoluble in excess |
| flame test | lilac flame | not tested |
Which row shows the identities of the ions present in P and Q?
Options
| P | Q | |
|---|---|---|
| A | and | and |
| B | and | and |
| C | and | and |
| D | and | and |
Four samples are analysed using paper chromatography.
P, Q and R are pure substances.
M is a mixture of different substances.
Which substances does mixture M contain?
Options
A P, Q and R
B P, Q and another substance
C P and Q only
D P and R only
A student is making a sample of aqueous copper(II) sulfate. The student adds an excess of copper(II) oxide powder to warm sulfuric acid and stirs the mixture.
Which apparatus is used to separate aqueous copper(II) sulfate from the excess copper(II) oxide?
Options
A burette
B distillation apparatus
C filter funnel and paper
D measuring cylinder
A sample of a white powder, X, is dissolved in water.
Tests are done on separate portions of this solution and the observations are shown in the table.
| test | observation |
|---|---|
| add aqueous sodium hydroxide a drop at a time until in excess | white precipitate forms, soluble in excess, giving a colourless solution |
| acidify with dilute nitric acid then add aqueous silver nitrate | white precipitate forms |
| acidify with dilute nitric acid then add aqueous barium nitrate | the solution remains colourless |
What is X?
Options
A aluminium chloride
B aluminium sulfate
C calcium chloride
D calcium sulfate
A chromatogram of mixture X and pure substances P, Q, R and S is shown.
Which statement is correct?
Options
A R is completely insoluble in the solvent used.
B The value of Q is greater than the value of S.
C X is a mixture of Q, R and S.
D The paper is placed in the solvent with the solvent above the baseline.
Sulfur dioxide is a gas that is prepared by heating sodium sulfite with hydrochloric acid. It is an acidic gas. Sulfur dioxide is more dense than air.
Which set of apparatus is suitable for preparing and collecting a dry sample of sulfur dioxide?
Options
A colourless solution of compound W is tested separately with a few drops of aqueous sodium hydroxide and a few drops of aqueous ammonia.
No precipitate is observed in either of the tests.
What is the cation in W?
Options
A
B
C
D