Page 25 - Focus SPM KSSM F4 2020 - Chemistry

Chemistry Form 4 Chapter 3 The Mole Concept, Chemical Formula and Equation
5. The state symbols (s), (l) and (g) represent the solid, liquid and gaseous states respectively. The symbol
(aq) represents the aqueous solution.
SPM Tips

Many students are not able to balance equations. You only need to adjust the coefficients in front of the formulae.
Never adjust the subscript numbers in the formulae because this will change the chemical formulae of the
substances. Balance all types of atoms, one at a time. Practice balancing equations regularly so that you can
master it.

ACTIVITY 3.3

Aim : To construct balanced chemical equations.
Materials : Copper(II) carbonate powder, limewater, concentrated hydrochloric acid, concentrated
ammonia solution, lead(II) nitrate solution and potassium iodide solution.
Apparatus : Test tubes, stoppers, delivery tubes with rubber bung, test tube holder, Bunsen burner and Chapter
glass tube.
Procedure: 3
A Heating of copper(II) carbonate
1. One spatulaful of copper(II) carbonate is placed in a test Copper(II) carbonate
tube. powder
2. The apparatus is set up as shown in Figure 3.18.
3. Copper(II) carbonate is heated and the gas produced is Heat
passed through lime water.
4. The changes of copper(II) carbonate and limewater are
observed. Limewater
5. When the reaction stops, the delivery tube is withdrawn Figure 3.18 Heating of copper(II) carbonate
from the limewater and the Bunsen burner is turned off.

B Formation of ammonium chloride
1. Using a glass tube, three to four drops of concentrated
hydrochloric acid are dropped into a test tube. The test tube Hydrogen
is stoppered and left aside for a minute. chloride Ammonia
gas gas
2. Using a clean glass tube, step 1 is repeated using concentrated
ammonia solution.
Figure 3.19 Formation of ammonium
3. Both stoppers are removed and the mouths of the test tubes chloride
are brought together as shown in Figure 3.19.

C Precipitation of lead(II) iodide
1. 2 cm of potassium iodide solution is added to 2 cm of Lead(II) Potassium
3
3
iodide solution
lead(II) nitrate solution as shown in Figure 3.20. nitrate
solution
2. The mixture is shaken and observed. Figure 3.20 Precipitation of lead(II)
iodide

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