Page 18 - Spotlight A+ Form 4 & 5 Chemistry KSSM

Form
4
Chemistry Chapter 5 Chemical Bond

5.7

1. Sodium chloride, NaCl and hydrogen chloride, HCl are two compounds that consist of chlorine, Cl element.
The melting point of sodium chloride, NaCl is 808 °C but the melting point of hydrogen chloride, HCl is
–114 °C. Explain why the melting points of the two compounds are different. C3
2. Table 1 shows the proton number of elements P and Q.
Element Proton number
P 12
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Q 17

Table 1
(a) What type of chemical bond is formed between: C2
(i) P and Q?
(ii) Q and Q?
(b) Explain why the compound formed by P and Q cannot conduct electricity in solid state but can
conduct electricity in aqueous or molten state. C3
(c) State whether the compound formed by Q and Q is an electrical conductor. Explain why. C3
(d) Between the compounds formed in (a)(i) and (a)(ii), determine which compound can dissolve in:
C3
(i) Water
(ii) Ethanol

SPM Simulation HOTS Questions

1 Which of the following particles contain 10 Examiner’s comment:
electrons? C4 • The properties above are for ionic
CHAP. [Proton number: Na = 11, Al = 13] compound. CHAP.
5 I Al III Na + • Lead(II) iodide and sodium chloride 5
II Na IV Al 3+ are ionic compounds but lead(II) iodide
A I and II C II and IV is insoluble in water.
B I and III D III and IV Answer: D

Examiner’s comment: 3. The electron arrangement of atom J is 2.8.2
• Al contains 13 electrons. and the electron arrangement of atom L is 2.7.
• Na contains 11 electrons.
+
• Na is the ion of Na which loses 1 electron. Elements J and L react to form a compound.
Thus, the number of electrons is 10. Write the chemical formula for the compound
• Al is the ion of Al which loses 3 electrons. formed and state two physical properties.
3+
Thus, the number of electrons is 10. C4
Answer: D
Examiner’s comment:
2 Compound Z has the following properties. J is a metal and L is a non-metal. An atom
• Soluble in water J will donate 2 electrons. Each of two atom
• Conduct electricity in aqueous or molten L will receive 1 electron from atom J. The
state ionic compound formed has the chemical
• Melting point = 800 °C formula JL .
2
Answer:
What is Z? C3 Chemical formula = JL 2
A Glucose The compound formed is soluble in water
B Naphthalene and has high melting point and boiling
C Lead(II) iodide point.
D Sodium chloride

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