Page 23 - Focus SPM KSSM F4 2020 - Chemistry

Chemistry Form 4 Chapter 3 The Mole Concept, Chemical Formula and Equation
Naming of chemical compounds
1. Chemical compounds are named systematically according to the guidelines given by the International
Union of Pure and Applied Chemistry (IUPAC).

Name of cation Name of anion
① The name of cation is
Magnesium sulphate written first followed by
Aluminium chloride the name of the anion.

② For elements that can form more
than one type of ion, Roman Lead(II) oxide 'II’ shows Pb ion
2+
numerals such as I and II are used to
differentiate the ions.
Lead(IV) oxide 'IV’ shows Pb ion
4+
Figure 3.14 Naming of ionic compounds

① The name of less Chapter
electronegative element ② The name of the more
is written first. Its name is electronegative element is
maintained as it is. added with the ending ~ide. 3
Hydrogen sulphide
Shows that there is one carbon Carbon dioxide
atom and two oxygen atoms in one ③ Greek prefixes such as ‘di’
molecule of CO . are used to show the number
2
of atoms of each element in
the molecule.
Figure 3.15 Naming of simple molecular compounds
Table 3.11 Example of names of simple molecular compounds
Chemical formula Name Note
CO Carbon monoxide Meaning of Greek prefixes:
SO Sulphur trioxide Mono = 1 ; Di = 2; Tri = 3 ;
3
CCl Carbon tetrachloride Tetra = 4 ; Penta = 5 ; Hexa = 6;
4
PCl Phosphorus pentachloride Hepta = 7 ; Octa = 8 ; Nona = 9;
5
Cl O 7 Dichlorin heptoxide Deca = 10
2
Checkpoint 3.3

[Relative atomic mass: N, 14; O, 16; Mg, 24, S, 32] Q4 Write the formula of the following ionic compounds.
Q1 A compound contains 23.3% of magnesium, 30.7% (a) Potassium sulphate (d) Ammonium carbonate
of sulphur and 46.0% of oxygen. What is the (b) Zinc chloride (e) Magnesium nitrate
empirical formula of the compound? (c) Tin(II) oxide (f) Sodium phosphate
Q2 A compound has a mass of 92 g mol . A sample of Q5 Name each of the following ionic compound.
-1
the compound is found to contain 0.606 g of nitrogen (a) Al(OH) (d) Ca(NO )
3 2
3
and 1.39 g of oxygen. (b) FeSO (e) K CO 3
4
2
(a) What is the empirical formula of the compound? (c) NH Cl (f) ZnS
4
(b) Hence, determine the molecular formula and Q6 A mixture contains carbon powder, magnesium
name of the compound.
hydroxide and iron(II) bromide. Write the chemical
Q3 Sodium thiosulphate has the formula of Na S O . formulae of the substances in the mixture.
2
2
3
(a) What is the mass of sulphur in 0.2 mole of Q7 Name each of the following molecular substances.
sodium thiosulphate? NO ; B O ; SF
(b) How many moles of oxygen atoms are present 2 3 6
in 79 g of sodium thiosulphate?
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