Chemical Formula/ Formula Kimia

Which chemical formula is correctly named according to the IUPAC nomenclature system?

Formula kimia manakah yang dinamakan dengan betul berdasarkan sistem penamaan IUPAC?

• MgO - Magensium oxide

  MgO - Magensium oksida

• SO₃ - Sulphur oxide

  SO₃ - Sulfur oksida

• CO - Carbon oxide

  CO - Karbon oksida

• Fe₂O₃ - Iron oxide

  Fe₂O₃ - Besi oksida

Which compound has the correct formula?

Sebatian manakah yang mempunyai formula yang betul?

• Barium nitrate - Ba(N0₃)₂

  Barium nitrat - Ba(N0₃)₂

• Lead(II) oxide - Pb0₂

  Plumbum(II) oksida - Pb0₂

• Copper (II) oxide - Cu₂0

  Kuprum(II) oksida - Cu₂0

• Silver carbonate - AgC0₃

  Argentum karbonat - AgC0₃

Diagram above shows the percentage by mass of elements in the allicin, which is a compound that causes

the smell in garlic. What is the empirical formula of allicin?

[Relative atomic mass : H = 1, C = 12, 0 = 16, S = 32]

Rajah di atas menunjukkan peratusan mengikut jisim bagi unsur dalam alisin iaitu sebatian yang menyebabkan bau

pada bawang putih. Apakah formula empirik bagi alisin?

[Jisim atom relatif: H = 1, C = 12, O = 16. S = 32]

• CHSO

• C₆H₁₀S₂O

• C₁₂H5S₂O

• C₁₂H₁₀S₄O

Diagram above shows the composition ofa coral reef. What is the empirical formula of the compound in the coral reef?

[Relative atomic mass : X = 40; Y=12; Z =16]

Rajah di atas menunjukkan komposisi suatu terumbu karang. Apakah formula empirik bagi sebatian dalam terumbu karang?[Jisim atom relatit X=40; Y =12; Z =16]

• XYZ

• XYZ₃

• XYZ₄

• X₃YZ

Diagram above shows the apparatus set-up to determine the empirical formula of magnesium oxide. Which step is correct to ensure the magnesium ribbon burnt completely?

Rajah di atas menunjukkan susunan radas untuk menentukan formula empirik magnesium oksida. Langkah manakah yang betul untuk memastikan pita magnesium itu terbakar dengan lengkap?

• Raise the crucible lid once in a while during heating

  Buka penutup mangkuk pijar sekali-sekala semasa pemanasan

• Heat the magnesium ribbon strongly in the crucible without its lid

  Panaskan pita magnesium itu dengan kuat dalam mangkuk pijar tanpa penutupnya

• Cover the crucible with its lid as soon as the magnesium ribbon starts burning

  Tutup mangkuk pijar dengan penutupnya sebaik sahaja pita magnesium itu mula terbakar

• Repeat the process of heating, cooling and weighing until a constant mass is obtained

  Ulang proses pemanasan, penyejukan dan penimbangan sehingga jisim tetap diperoleh

Diagram above shows the set up of the apparatus to determine the empirical formula of a metal oxide. Which of the following metal oxide is suitable to be used in diagram above?

Rajah di atas menunjukkan susunan radas untuk menentukan formula empiric suatu oksida logam. Antara oksida logam berikut, yang manakah sesuai digunakan dalam rajah di atas?

• Zinc oxide

  Zink oksida

• Aluminium oxide

  Aluminium oksida

• Magnesium oxide

  Magnesium oksida

• Copper(II) oxide

  Kuprum(ll) oksida

Diagram above shows the apparatus set-up to determine the empirical formula of copper(II) oxide. The dry hydrogen gas must be flowed through the apparatus for several minutes before heating the copper(II).

oxide. What is the reason for this action to be taken?

Rajah di atas menunjukkan susunan radas bagi menentukan formula empirik bagi kuprum(II) oksida. Gas hidrogen kering mesti dialirkan melalui radas untuk beberapa minit sebelum pemanasan kuprum(II) oksida.

Apakah sebab tindakan ini diambil?

• To ensure all the copper(II) oxide has changed into copper

  Untuk memastikan semua kuprum(II) oksida telah bertukar kepada kuprum

• To ensure all air has been removed so that explosion can be prevented

  Untuk memastikan semua udara dikeluarkan supaya letupan dapat dielakkan

• To prevent copper from reacting with air to form copper(I I) oxide

  Untuk mengelakkan kuprum daripada bertindak balas dengan udara bagi membentuk kuprum(II) oksida

• To prevent the water from flowing towards the hot porcelain dish and cracks the combustion tube

  Untuk mengelakkan air daripada mengalir ke arah piring parselin yang panas dan meretakkan tiub pembakaran

Which compound has the empirical formula of CH₂0?

Sebatian manakah yang mempunyai formula empirik CH₂0?

• HCOOH

• CH₃COOH

• CH₃COOCH₃

• HCOOC₂H₅

5 g of element X reacted with 8 g of element Y to form a compound with the formula XY₂.

What is the relative atomic mass of element X? [Relative atomic mass of Y=80]

5 g unsur X bertindak balas dengan 8 g unsur Y untuk membentuk sebatian yang mempunyai formula XY₂.

Berapakah jisim atom relatif unsur X? [Jisim atom relatif Y=80]

• 25

• 40

• 50

• 100

A compound of magnesium nitrite contains 72 % of magnesium and 28 % of nitrogen.

What is the empirical formula of magnesium nitrite? [Relative atomic mass: N = 14; Mg= 24]

Suatu sebatian magnesium nitrit mengandungi 72% magnesium dan 28% nitrogen.

Apakah formula empirik bagi magnesium nitrit? [Jisim atom relatif. N = 14; Mg= 24]

• MgN₂

• Mg₂N

• Mg₂N₃

• Mg₃N₂