Page 4 - Modul A+ Kimia Tg 4_Pan Asia Publications

7. Berdasarkan skala karbon-12, jisim atom relatif, JAR sesuatu unsur ialah jisim purata satu atom
1 karbon-12
unsur itu apabila dibandingkan dengan kali jisim satu atom .
12
Based on the carbon-12 scale, the relative atomic mass, RAM of an element is the average mass of one atom of
1 carbon-12
the element when compared with times the mass of one atom.
12

Jisim purata satu atom unsur/ Average mass of one atom of the element
Jisim atom relatif, JAR =
Relative atomic mass, RAM 1 × jisim satu atom karbon-12/ mass of one atom of carbon-12
12

Contoh/ Example:
©PAN ASIA PUBLICATIONS
1 daripada satu atom karbon-12
12 C-12
1 of a carbon-12 atom
12
He
1 daripada satu atom karbon-12
12
1 of a carbon-12 atom
12

Rajah/Diagram 3.1

1
Berdasarkan Rajah 3.1, jisim 1 atom helium adalah 4 kali lebih besar daripada 12 kali jisim satu atom
karbon-12.
4 1
Based on Diagram 3.1, the mass of 1 helium atom is times greater than 12 times of the mass of one carbon-12
atom.
Maka, jisim atom relatif, JAR atom helium/ Therefore, the relative atomic mass, RAM of helium atom = 4

Contoh/ Example: 1
Diberi jisim 1 atom nitrogen ialah 14 kali lebih besar daripada kali jisim satu atom karbon-12. Tentukan jisim atom
12
relatif, JAR bagi satu atom nitrogen. 1
Given that the mass of 1 nitrogen atom is 14 times greater than 12 times the mass of 1 carbon-12 atom. Determine the relative
atomic mass, RAM of a nitrogen atom.
1
Jisim satu atom nitrogen = 14 kali lebih besar daripada kali jisim 1 atom karbon-12
12
1
Mass of one nitrogen atom = 14 times greater than times the mass of 1 carbon-12 atom
12
14 kali lebih besar Jisim karbon-12
14 times greater 1 Mass of carbon-12
= 14  [ 12  12 ]
= 14
∴ Jisim atom relatif, JAR atom nitrogen/ Relative atomic mass, RAM of nitrogen atom = 14

Contoh/ Example:
Tentukan berapa kali 2 atom argentum lebih besar daripada 4 atom aluminium.
Determine how many times greater are 2 silver atoms compared to 4 aluminium atoms.
[JAR/ RAM: Al = 27; Ag = 108]
Jisim 2 atom argentum = Q kali lebih besar daripada jisim 4 atom aluminium
Mass of 2 silver atoms = Q times greater than the mass of 4 aluminium atoms
Q kali lebih besar
Q times greater
2 atom Ag 4 atom Al
2 Ag atoms 4 Al atoms
2(108) = Q  4 (27)
JAR Ag 216 = Q  108 JAR Al
RAM of Ag RAM of Al
216 = Q
108
Q = 2
∴2 atom argentum ialah 2 kali lebih besar daripada 4 atom aluminium.
2 silver atoms are 2 times greater than 4 aluminium atoms.

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