Chemistry SPM Practical Test 2021

Why are chemists great
for solving problems?

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Test The Mastery of 11 Scientific Skills
1. Observing
2. Classifying
3. Inferring
4. Measuring (burette, stopwatch, thermometer, voltmeter)
5. Predicting
6. Communicating (e.g construct table and draw graph)
7. Space-Time Relationship
8. Interpreting Data
9. Defining Operationally
10.Controlling Variables
11.Hypothesizing

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Answers are given in the question!
MV and RV are stated in the question, stimulus,

diagram etc……

Tips

Identify the MV and RV first from the question

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1. Statement of the problem
How does MV affect RV?
Does increasing MV increase the RV?

2. Making Hypothesis (Must relate the MV to the RV)
The higher the MV, the higher the RV
When MV decreases, RV decreases.

(Remember – no neutral relationship terms like ‘affects’ or
‘influence’ , ‘depends on’ or ‘changes with’)

3. Operational Definition
What you do and what you see (RV)

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Action + Material + Apparatus

Example
 Clean metal strip with sand paper
 Cut sodium into small pieces with knife and forceps
 Measure 50 cm3 of 0.20 mol dm-3 sodium thiosulphate using

measuring cylinder
 Connect the electrodes with connecting wire to the

voltmeter
 Pour 50cm3 0.1 mol dm-3 of hydrochloric acid into the

beaker

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4. Procedure :

1. Draw diagrams for the set-up of apparatus – not required
but encouraged

2. Explain the set-up of apparatus.
3. Describe the ways to control/fix the CV.
4. Describe what is done to the MV1.
5. Describe the ways to measure the RV.
6. Repeat the steps by replacing MV1 with MV2.

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5. Tabulation of data:
Construct the table with the correct titles and
units

MV RV

Remember to write unit in the MV and RV column (if any)

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Procedure :
• All the steps taken in the procedure must include the

apparatus used, quantity( volume, mass or concentration)

and type of substance.

Chemical measurement Suggestion of the suitable range of
chemical quantity

Volume of salt solution, alkali 25 - 250 cm3
or acid (usually 50 cm3 is chosen)

Mass of solid, such as marble 5 – 10 g
or zinc (usually 5 g is chosen)

Concentration of salt solution, 0.1 – 2 mol dm-3
alkali or acid (usually 1 mol dm-3 is chosen)

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The operational definition of ionic compound:

What you do What you observe(RV)

(electrodes dipped into (the bulb lights up)
compound)

Ionic compound is a
substance that causes
the bulb to light up
when two carbon electrodes
connected to the battery are
dipped into the compound.

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The operational definition of ionic compound:

What you do What you observe(RV)

(electrodes dipped (ammeter needle deflects)
into compound)
Ionic compound is a substance
that causes
the ammeter needle to deflect
when two carbon electrodes
connected to the battery are
dipped into the compound.

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How to measure?
What to see?

The operational definition for the rate of reaction
for this experiment:

What you do What you observe(RV)

Add sulphuric acid Time taken for ‘X’ mark to disappear from view

The rate of reaction is the time taken for ‘X’ mark to
disappear from view when sulphuric acid is added
into sodium thiosulphate solution.

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The operational definition for coagulation of latex:

How to measure?
What to see?

What you do What you observe

(add acid) (white solid)

Coagulation of latex is the formation
white solid when acid is added to latex.

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The operational definition for heat of displacement:

What you do What you observe

(excess zinc powder is (temperature rise/ change)
added into copper(II)
sulphate solution )

Heat of displacement is the temperature rises
when excess zinc powder is added into copper(II)

sulphate solution.

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The operational definition for the neutralisation of acid or alkali :

What you do What you observe

(add acid base indicator) (change in colour)

Neutralisation is a process

when acid is added to alkali solution
containing phenolphthalein indicator,
the pink solution changes to colourless.

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The operational definition of acid:

How to measure?
What to see?

What you do What you observe

(dissolved in water) (blue litmus paper turns red)

Acid is a substance that turns the
blue litmus paper red when water is added.

Blue litmus paper

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For example: How to
measure?

The operational definition for the reactivity of

Group 1 elements towards water:

What you do What you observe

(react with water) (how vigorous the metal moves)

The Group 1 elements that reacts/ moves
more vigorously and rapidly with water
is a more reactive metal.

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The operational definition for reactivity of
Metal towards oxygen:

What you do What you observe

(Reaction with oxygen) (Flame produced)

Reactivity of metals is the brightness of

flame/glow produced when the metal
powder is heated/burned with oxygen.

The brighter the flame, the more reactive
the metal towards oxygen.

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Accuracy in taking measurements

Degree of accuracy depends on the type and
calibration of instrument used.

3
2

1 or 2
1
1
1

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Burette

10.25 cm3

2 decimal places

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28.85 cm3

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76.00 cm3

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25.50 cm3 18.00 cm3

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Voltmeter

0.1 = 0.05
2

https://youtu.be/JFCGT80IWUw 2.70 V 2 decimal places

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0.2 = 0.1 1 decimal places
2

2.8 V

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0.2 = 0.1
2

1.5 V
1 decimal place

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Stopwatch

1 = 0.5 s
2

1 decimal place

40.0 s

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Digital Stopwatch 2 decimal places

15.01 s
19.90 s
27.73 s
45.88 s
70.85 s

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Thermometer

Initial temperature : 30.0C Final temperature : 59.0C

1 decimal place

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• Colourless gas bubbles release
• Magnesium ribbon dissolves

• Hydrogen gas is released when magnesium reacts
with acid.

• Magnesium reacts with hydrochloric acid to produce
magnesium chloride solution.

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Concentration of hydrochloric acid.

Rate of reaction// time taken for gas bubbles to release/
time taken for complete reaction
Size/ length of magnesium ribbon// volume of
hydrochloric acid.

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Rate of reaction is time taken for the bubble gaseous
release when hydrochloric acid reacts with metal /
Rate of reaction is time taken for metal to dissolves
completely when reacts with acid.

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1. Clean all the metal electrode with sandpaper.
2. Pour 10 cm3 of 2.0 mol dm-3 hydrochloric acid up to two-thirds full with

into a beaker.
3. Connect Copper electrode(Electrode A) and zinc electrode(Electrode

B) to the voltmeter using connecting wire with crocodile clip.
4. Dip both the electrodes in the beaker containing hydrochloric acid.
5. Record the voltmeter reading.
6. Determine and record the negative and positive terminal.
7. Repeat steps 1 to 6 are by using magnesium, tin and iron to replace

zinc as electrode B.

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