Learners' AlleyDesigned by Khow Willard

Practical Chemistry and Qualitative Analysis

Set BCompetition Practice

Name

Time 20 minutes

Total 13 marks

Competition questions

13 marks

An experiment was conducted to measure the temperature change caused by adding a known quantity of sodium carbonate to an excess of dilute acid. Besides a thermometer and styrofoam cup, these apparatus are available.

1 gas syringe
2 mass balance
3 measuring cylinder
4 stopwatch

Which pieces of apparatus are needed for this experiment?

A1, 2, 3 and 4

B2 and 3 only

C2 and 4 only

D4 only

Answer [1]

Source: 2024 AES O Prelim P1 Q1

A student investigates the rate of reaction between an excess of acid of different concentrations and a known quantity of calcium carbonate granules. During the reaction, the student measures the volume of gas released.

In addition to a conical flask and a balance, the following pieces of apparatus are available.

1 gas syringe
2 thermometer
3 measuring cylinder
4 stopwatch

Which pieces of apparatus are needed for this experiment?

A1, 3 and 4 only

B1 and 3 only

C1 and 4 only

D2, 3 and 4 only

Answer [1]

Source: 2024 Dunman O Prelim P1 Q1

The setup used to dry gas Q is shown.

What can be deduced about gas Q?

AGas Q is denser than air.

BGas Q is either acidic or neutral.

CGas Q is insoluble in water.

DGas Q is soluble in concentrated sulfuric acid.

Answer [1]

Source: 2024 Jurongville O Prelim P1 Q1

The diagrams show two methods of gas collection.

Which pair of gases can be collected by both methods?

Aammonia and hydrogen

Bcarbon dioxide and sulfur dioxide

Chydrogen and methane

Dnitrogen and hydrogen chloride

Answer [1]

Source: 2026 Dunman O Prelim P1 Q2

The diagram shows an experimental setup to produce and collect a dry sample of gas X.

What is gas X?

Aammonia gas

Bhydrogen chloride gas

Chydrogen gas

Dsteam

Answer [1]

Source: 2024 Dunman O Prelim P1 Q2

A student titrated 25.0 cm³ of hydrochloric acid with 0.1 mol/dm³ aqueous sodium hydroxide, using methyl orange. Which step would make her calculated concentration of hydrochloric acid higher than its true value?

AThe burette was rinsed with distilled water followed by aqueous sodium hydroxide.

BThe conical flask was rinsed with distilled water followed by hydrochloric acid.

CThe titration reading was taken when methyl orange turned orange.

DThe burette was read at an angle.

Answer [1]

2024 Serangoon O Prelim P1 Q16

Tests are done to identify an unknown salt P.

step	test	observations
1	Dissolve 5 g of P in 10 cm³ of water.	Green solution formed.
2	To a sample, add aqueous ammonia dropwise and allow it to stand for 5 minutes.	Green precipitate formed, which turns reddish-brown.
3	To another sample, add nitric acid followed by aqueous barium nitrate.	White precipitate formed.

What is the formula of salt P?

ACuSO₄

BFeCl₃

CFeSO₄

DFe₂(SO₄)₃

Answer [1]

2024 Zhonghua O Prelim P1 Q20

10.0 cm³ of 1.0 mol/dm³ aqueous iron(II) sulfate was mixed with 10.0 cm³ of 1.0 mol/dm³ aqueous sodium hydroxide: FeSO₄(aq) + 2NaOH(aq) → Fe(OH)₂(s) + Na₂SO₄(aq). What did the flask contain when the reaction was complete?

AA green precipitate only.

BA green precipitate in a colourless solution.

CA white precipitate in a green solution.

DA green precipitate in a green solution.

Answer [1]

2024 CHIJ O Prelim P1 Q21

An aqueous solution contains 0.01 mol of zinc ions and 0.01 mol of copper(II) ions. Aqueous ammonia is added until in excess. After shaking, the mixture is filtered. What remains on the filter paper?

A0.01 mol of a blue hydroxide

B0.01 mol of a white hydroxide

C0.01 mol of a white hydroxide and 0.01 mol of a blue hydroxide

Dno solid residue

Answer [1]

2024 Bukit View O Prelim P1 Q23

P is a white powdery solid. P dissolved in distilled water to form a blue solution. The solution was divided into two test tubes. In the first, a blue precipitate formed on dropwise addition of aqueous ammonia, which dissolved in excess to form a deep blue solution. In the second, a white precipitate formed on adding an equal volume of acidified aqueous barium nitrate. The mixture was filtered and the filtrate crystallised to give solid Q. What are P and Q?

	P	Q
A	barium sulfate	barium sulfate
B	barium sulfate	copper(II) nitrate
C	copper(II) sulfate	barium sulfate
D	copper(II) sulfate	copper(II) nitrate

Arow A

Brow B

Crow C

Drow D

Answer [1]

2023 Catholic High School O Prelim P1 Q7

A student reacted excess calcium with hydrochloric acid and carried out tests on the reaction mixture. Which observation does not show that the reaction has occurred?

	test	observation
A	Add dilute nitric acid followed by aqueous silver nitrate.	white precipitate
B	Weigh the reaction mixture at the start and at the end.	mass decreases
C	Test the pH of the mixture at the start and after 30 s.	pH increases
D	Add aqueous sodium hydroxide until no further change.	white precipitate insoluble in excess

Arow A

Brow B

Crow C

Drow D

Answer [1]

2024 SCGS O Prelim P1 Q6

Which method would not produce ammonia?

Acompressing hydrogen and nitrogen at a high temperature with an iron catalyst

Bheating ammonium sulfate with hydrochloric acid

Cheating an alkaline solution containing calcium nitrate and aluminium powder

Dwarming concentrated aqueous ammonia

Answer [1]

2026 Dunman O Prelim P1 Q16

Measured values of the pressure, volume and temperature of a known mass of a gas are substituted into the ideal gas equation to calculate its relative molecular mass. Which conditions would give the most accurate value of M_r?

	pressure	temperature
A	high	high
B	high	low
C	low	high
D	low	low

Arow A

Brow B

Crow C

Drow D

Answer [1]

2021 YIJC J1 MYE P1 Q14