Manufactured Substance In Industry Form 4

Substance X conducts electricity in the solid state and also in the molten state. Substance X is

• an alloy

• a salt

• a fat

• a metal oxide

The diagram shows the arrangement of atom in brass. Why is brass harder than pure copper?

• Zinc atoms form very strong hydrogen bonds with copper atoms.

• Zinc atoms prevent the layers of copper atoms from sliding over each other.

• Zinc atoms prevent electrons from moving freely in the sea of electrons.

• Zinc atom contributes more electrons to the sea of electrons.

1. The body of an aeroplane is made from duralumin. Which of the following are the composition of duralumin?

• Copper and tin

• Copper and zinc

• Aluminium , copper, magnesium and manganese

• Iron, carbon and chromium

8.The purposes of making alloys are

I.to lower the melting points of pure metals

II.to improve the appearance of pure metals

III.to increase the strength and hardness of pure metals

IV.to improve the resistance to corrosion of pure metals

• A.I,III

• B.II,IV

• C.II, III,IV

• D I, II, III, IV

The diagram below shows the orderly arrangement of atoms in a metal. The arrangement of atoms makes a metal ductile because

• A.the forces of attraction between the metal atoms are very weak

• B.the forces of attraction between the metal atoms are very strong

• C.the forces of attraction between the layers of atoms are very strong

• D.the layers of metal atoms can slide over one another when force is applied

The main substance in the making of all types of glass is

• calcium carbonate

• sodium carbonate

• lead(II) oxide

• silicon dioxide

Silicon dioxide, SiO₂ which exist naturally in sand.

Silikon dioksida, SiO₂ yang wujud semula jadi dalam pasir.

• True / Betul

• False / Salah

What type of glass is formed when calcium carbonate is heated with silicon dioxide?

• Fused glass

• Borosilicate glass

• Lead crystal glass

• Soda lime glass

Diagram 1 shows several products of a substance. Which of the following is the substance?

• Optic glass

• Fused glass

• Fibre glass

• Photochromic glass

Which of the following is the chemical reaction that occurs when photochromic glass darkens?

• AgCl ⟶ Ag⁺ + Cl^-

• Ag⁺ + e^- ⟶ Ag

• Clˉ + UV ⟶ Cl

• Cl + e^- ⟶ Clˉ