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MODULE • Chemistry Form 4

(iv) Calculate the percentage by mass of nitrogen in compound Z.
[Relative atomic mass: N = 14, S = 32, O = 16, H = 1]
Hitungkan peratusan jisim nitrogen dalam sebatian Z.
[Jisim atom relatif: N = 14, S = 32, O = 16, H = 1]
2 × 14
%N = × 100% = 21.2%
2(14 + 4 × 1) + 32 + 4 × 16
2 The table shows the examples and component of four types of manufactured substances in industry.
Jadual berikut menunjukkan contoh-contoh dan komponen bagi empat jenis bahan buatan dalam industri.
Type of manufactured Example Component
substances
Jenis bahan buatan Contoh Komponen
Reinforced concrete Cement, sand, small pebbles and steel
P
Konkrit yang diperkukuhkan Simen, pasir, batu kecil dan keluli
Q Bronze / Gangsa Copper and tin / Kuprum dan stanum
Polymer / Polimer R Chloroethene / Kloroetena
Silicon dioxide, sodium carbonate, calcium carbonate
Glass / Kaca S
Silikon dioksida, natrium karbonat, kalsium karbonat
(a) State the name of P, Q, R and S.
Namakan P, Q, R dan S.
P: Composite materials Q: Alloy

R: Polyvinyl chloride S: Soda-lime glass
(b) (i) State two uses of reinforced concrete.
Nyatakan dua kegunaan konkrit yang diperkukuhkan.
To make framework of buildings and bridges.

(ii) What is the advantage of using reinforced concrete compared to concrete?
Apakah kelebihan konkrit yang diperkukuhkan berbanding dengan konkrit?
Reinforced concrete can withstand higher pressure/support heavier loads/ stronger/ higher tensile strength

than concrete.
(c) (i) Draw the arrangement of particles in
Lukis susunan atom dalam

Pure copper / Kuprum tulen Bronze / Gangsa

Copper

Tin
Copper

(ii) Bronze is harder than pure copper. Explain.
Gangsa lebih keras daripada kuprum. Terangkan.
– Atoms of pure copper metal are the of same size, they arranged orderly in layers.
– Layers of atoms are easily slide over each other when external force is applied on them.

– The size of tin atoms which are bigger than copper in bronze disrupt the orderly arrangement of copper
atoms.
– Layers of metal atoms are prevented from sliding each other when external force is applied.

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