Question

1. 4541/3
Answer all questions
1. Diagram 1.1 shows the set-up of apparatus for an experiment to compare the hardness
of a bronze and its pure metal, copper.
Thread
1 kg weight
Retort stand
Ruler
Cellophane tape
1

2. 4541/3
Steel ball bearing
Copper block
Diagram 1.1
The experiment was carried out according the following steps:
Step 1 A steel ball bearing is taped onto the copper block.
Step 2: A 1 kg weight is hung at a height of 50 cm above the copper block
as shown in diagram 1.1
Step 3: The weight is allowed to drop onto the ball bearing.
Step 4: The diameter of the dent made on the copper block was measured.
2

3. Step 5: Step1 to 4 are repeated on two other parts of the copper block in
order to obtain an average value for the diameter of dents formed.
Step 6: Step 1 to 5 are repeated by the replacing the copper block with
bronze block.
Diagram 1.2 shows the shape of dents formed for the experiment.
Steel ball bearing
Copper block
Diagram 1.2

4. 4541/3
Table 1.1 (a) shows the three dents formed on the copper block.
Sets Diagram of the dents formed Diameter of
the dent
(cm)
I
Copper block
Ruler
...................
II
Copper block
Ruler
...................
III
Copper block
Ruler
.....................
Table
1.1(a)

5. Table 1.1 (b) shows the three dents formed on the bronze block.
Sets Diagram of the dents formed Diameter of
the dent
(cm)
I
Bronze block
Ruler
.....................
II
Bronze block
Ruler
.....................
III
Bronze block
Ruler
.....................
Table 1.1 (b)

6. (a) (i) By using a ruler given, measure the diameters of the dents made on
copper
bronze
blocks.
Record
the
diameters
of
dents
Table
1.1(a)
1.1
1(a)
(i)
]
(ii)
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o
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p
p
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r
a
n
d
b
r
o
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b
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o
c
k
s
.

7. [3 marks]
(b) State one observation for this experiment.
……………………………………………………………………………………
…
………………………………………………………………
………………………
[3 marks]
(c) Based on the average diameter of the dents copper
and bronze blocks, state the inference that can be
made.
………………………………………………………………
……
……
……
……
…
[3 marks]

8. 4541/3
(d) Based on this experiment, complete Table 1.2.
Type of variable Action to be taken

9. 4541/3
(i) Manipulated variable
……………………………………
.
…………………………………….
.
……………………………………
.
(ii) Method to manipulated
variable:
…………………………………….
…………………………………….
…………………………………….
…………………………………….
(iii) Responding variable:
……………………………………
.
……………………………………
.
……………………………………
.
(iv) What to observe in
the responding
variable:
…………………………………….
……………………………………..
……………………………………..
……………………………………
…(v) Fixed variable;
…………………………………
…
…………………………………
…
…………………………………
…
(vi) Method to maintain the
fixed variable:
…………………………………….
.
.
…………………………………….
……………………………………
…
[6 marks]
[6 markah]

10. (e) State the hypothesis for this experiment.
………………………………………………………………………………………
(f) State the operational definition of an alloy for the eksperiment.
[3 marks]
………………………………………………………………………………………
………………………………………………………………………………………
[3 markah]
(g) State the relationship between diameter of dent and hardness of the
material.
………………………………………………………………………………………..
[3 marks]
(h) Explain why there is a difference in diameter of the dents on copper and
bronze blocks.
……………………………………………………………………………………....
………………………………………………………………………………………
[3 marks]

11. (i) The following is a list of materials:
Brass Pewter Aluminium
Stainless steel Tin Iron
Classify the following materials into pure metal and alloy.
Pure metal All
oy
[3 marks]

12. 2.
NaCl + H2
O ∆H= -57.5 kJmol-1
Experiment 1 : NaOH + HCl
CH3
COONa + H ∆H= -55 kJmol-1
Experiment II : NaOH + CH3
COOH
The value of the heat of neutralization for the reaction between
sodium hydroxide solution and strong acid solution is higher than the value of the heat of
neutralization for the reaction between sodium hydroxide solution and weak acid solution.
Based on the above statement, you are required to design an experiment to
determine and compare the heat of neutralization between sodium hydroxide
solution with a names strong acid solution and a weak solution.
Your planning should be include the followings:
(a) Problem Statement
(b) Hypothesis
(c) All the variables
(d) List of materials and apparatus
(e) Tabulation of data
[17 marks]
END OF QUESTION PAPER