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Chemistry Form 4 • MODULE

CHEMICAL EQUATIONS / PERSAMAAN KIMIA

1 Two types of equation / Dua jenis persamaan:
• Equation in words / Persamaan perkataan
– using names of reactants and products / menggunakan nama bahan tindak balas dan hasil tindak balas;
• Equation using symbols / Persamaan menggunakan simbol
– reactants and products are represented by chemical formulae and have certain meanings
menggunakan formula kimia untuk mewakili bahan tindak balas dan hasil tindak balas serta menggunakan pelbagai jenis simbol yang
membawa makna tertentu.

Symbol / Simbol Meaning / Maksud Symbol / Simbol Meaning / Maksud
Separating 2 reactants / products (g) Gaseous state
+
Mengasingkan 2 bahan / hasil (g) Keadaan gas
Produces (aq) Aqueous state
Menghasilkan (ak) Keadaan akueus

Reversible reaction Gas released

Tindak balas berbalik Gas terbebas
(s) Solid state Precipitation
(p) Keadaan pepejal Bahan termendap
(l) Liquid state ∆ Heating / Heat energy is given
(ce) Keadaan cecair Pemanasan / Haba dibekalkan

2 Information obtained from chemical equation using symbols / Maklumat yang diperoleh daripada persamaan kimia bersimbol:
(a) Qualitative aspect / Aspek kualitatif : type of reactants and products involved in the chemical reaction and the state
of each reactant and product.
jenis bahan / hasil tindak balas yang terlibat dalam tindak balas dan keadaan fizikal bagi
setiap bahan / hasil tindak balas.
(b) Quantitative aspect / Aspek kuantitatif : number of moles of reactants and products involved in the chemical reaction
that is the coeffficients involved in a balanced equation of the formulae of
reactants and products.
bilangan mol yang bertindak balas dan hasil tindak balas yang terbentuk iaitu pekali bagi
setiap formula bahan dan hasil tindak balas.
Example / Contoh:
Zn (s) + 2HCl (aq) ZnCl (aq) + H (g)
2 2
Zn (p) + 2HCl (ak) ZnCl (ak) + H (g)
2
2
1 mol 2 mol 1 mol 1 mol
Interpretation / Tafsiran: 1 mol of zinc reacts with 2 mol of hydrochloric acid to produce 1 mol of zinc chloride and
1 mol of hydrogen.
1 mol zink bertindak balas dengan 2 mol asid hidroklorik menghasilkan 1 mol zink klorida dan 1 mol hidrogen.

3 Writing balanced chemical equations / Menulis persamaan kimia seimbang:
Step 1 / Langkah 1 : Write the correct chemical formulae for each reactant and product.
Tulis formula kimia bagi setiap bahan dan hasil tindak balas.
Step 2 / Langkah 2 : Detemine the number of atoms for each element / Tentukan bilangan atom setiap unsur.
Step 3 / Langkah 3 : Balance the number of atoms for each element by adjusting the coefficients in front of the chemical
formulae.
Imbangkan bilangan atom setiap jenis unsur dengan menambahkan pekali di hadapan setiap formula kimia.

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