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MODULE • Chemistry Form 4

(c) 1 mol of NH 0.25 × 6.02 × 10 23 molecules of ammonia, NH / molekul ammonia, NH 3
3
4 3 0.25 mol of N atoms / mol atom N,
[Ammonia gas] number of N atoms / bilangan atom N = 0.25 × 6.02 × 10 23
1 1 mol of atoms
mol NH
4 3 1
[Gas ammonia] mol atom 0.75 mol of H atoms / mol atom H,
23
number of H atoms / bilangan atom H = 0.75 × 6.02 × 10
2+
(d) 2 mol of MgCl 2 2 mol of Mg ions / mol ion Mg ,
2+
[Magnesium chloride] number of Mg ions / bilangan ion Mg = 2 × 6.02 × 10 23
2+
2+
2 mol MgCl 2
[Magnesium klorida] 4 mol of Cl ions / mol ion Cl ,
–
–

-
number of Cl ions / bilangan ion Cl = 4 × 6.02 × 10 23
–
(e) 2 mol of SO 2 2 × 6.02 × 10 23 molecules of SO / molekul SO 2
2
[Sulphur dioxide] 2 mol of S atoms / mol atom S,
2 mol SO 2 number of S atoms / bilangan atom S = 2 × 6.02 × 10 23
[Sulfur dioksida] 3 × 2 = 6 mol of atoms

3 × 2 = 6 mol atom 4 mol of O atoms / mol atom O,
number of O atoms / bilangan atom O = 4 × 6.02 × 10 23
10 Complete the table below:
Lengkapkan jadual berikut:
Number of moles Number of particles
Bilangan mol Bilangan zarah
0.5 mole of carbon, C 3.01 × 10 atoms of carbon
23
0.5 mol atom karbon, C 3.01 × 10 atom karbon
23
0.2 moles of hydrogen gas, H 2 (i) 0.2 × 6.02 × 10 23 molecules of hydrogen / molekul hidrogen
0.2 mol gas hidrogen, H
2 23
(ii) 2 × 0.2 × 6.02 × 10 atoms of hydrogen / atom hidrogen
1 mole of carbon dioxide molecules, CO 6.02 × 10 molecules of carbon dioxide contains:
23
1 2 6.02 × 10 molekul karbon dioksida mengandungi:
23
mol molekul karbon dioksida, CO
2 6.02 × 10 23 atoms of C and 2 × 6.02 × 10 23 atoms of O.
6.02 × 10 23 atom C dan 2 × 6.02 × 10 23 atom O.

NUMBER OF MOLES AND MASS OF SUBSTANCE / BILANGAN MOL DAN JISIM BAHAN

1 Molar mass / Jisim molar
(a) Molar mass is the mass of one mole of any substance / Jisim molar adalah jisim satu mol sebarang bahan.
(b) Molar Mass is the relative atomic mass, relative molecular mass and relative formula mass of a substance in
g mol .
–1
Jisim molar adalah jisim atom relatif, jisim molekul relatif dan jisim formula relatif suatu bahan dalam g mol .
–1
(c) Molar mass of any substance is numerically equal to its relative mass (Relative atomic mass/ relative formula
mass/relative molecular mass).
Jisim molar sebarang bahan mempunyai nilai yang sama dengan jisim relatif (Jisim atom relatif/ jisim formula relatif/ jisim molekul
relatif).
2 Example / Contoh:
Molar mass of H O = 18 g mol –1
2
Jisim molar H O = 18 g mol –1
2
Mass of 1 mol of H O = 18 g × RAM/ /RFM/RMM
2
Jisim 1 mol H O = 18 g Number of × JAR/JFR/JMR Mass in gram
2
Mass of 2 mol of H O = 2 mol × 18 g mol = 36 g moles
–1
2 Bilangan mol ÷ RAM/ /RFM/RMM Jisim dalam gram
–1
Jisim 2 mol H O = 2 mol × 18 g mol = 36 g ÷ JAR/JFR/JMR
2
Mass of 2.5 mol of H O = 45 g
2
Jisim 2.5 mol H O = 45 g
2
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