Page 8 - Nilam_Publication_module_Chemistry_Form.pdf

MODULE • Chemistry Form 4

(a) A boiling tube is filled 3 - 5 cm height with naphthalene powder and a thermometer is
placed into it.
Tabung didih diisi dengan serbuk naftalena setinggi 3 – 5 cm dan termometer diletakkan
di dalamnya.

(b) The boiling tube is immersed in a water bath as shown in the diagram so that the water level in the water bath
is higher than naphtalene powder in the boiling tube.
Tabung didih dimasukkan ke dalam kukus air seperti di dalam gambar rajah dan pastikan aras air dalam kukus air lebih tinggi
daripada aras naftalena dalam tabung didih.
(c) The water is heated and the naphthalene is stirred slowly with thermometer .
Air dipanaskan dan naftalena dikacau perlahan-lahan dengan termometer .

(d) When the temperature of naphthalene reaches 60°C , the stopwatch is started. The temperature of
naphthalene is recorded at 30 seconds intervals until the temperature of naphthalene reaches 90°C .
Apabila suhu naftalena mencapai 60°C , mulakan jam randik. Suhu naftalena dicatat setiap 30 saat
sehingga suhunya mencapai 90°C .

II. Cooling of naphthalene / Penyejukan naftalena

Naphthalene
Naftalena

(a) The boiling tube and its content is removed from the water bath and put into a conical flask as shown
in the diagram.
Tabung didih dan kandungannya dikeluarkan daripada kukus air dan dipindahkan ke dalam kelalang kon seperti
dalam gambar rajah.
(b) The content in the boiling tube is stirred constantly with thermometer throughout cooling
process to avoid supercooling (the temperature of cooling liquid drops below freezing point, without
the appearance of a solid).

Kandungan dalam tabung didih dikacau perlahan-lahan dengan termometer sepanjang proses penyejukan untuk
mengelakkan penyejukan lampau (Suhu cecair yang disejukkan turun melepasi takat beku tanpa pembentukan
pepejal).
(c) The temperature of naphthalene is recorded every 30 seconds interval until the temperature drops
to 60°C .
Suhu naftalena dicatat setiap 30 saat sehingga suhunya mencapai 60°C .
(d) A graph of temperature against time is plotted for the heating and cooling process respectively.

Graf suhu melawan masa dilukis untuk proses pemanasan dan penyejukan.

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