Kuiz Sains Tambahan Tingkatan 5 Bab 4 Set 1

SELAMAT DATANG Kuiz Sains Tambahan Tingkatan 5 Bab 4 Set 1

Tenaga Dan Perubahan Kimia (English)

KUIZ INI MENGANDUNGI 10 SOALAN

During the electrolysis of molten lead(II) bromide (PbBr2), which products are formed at the anode and cathode respectively?

Lead(II) ions at the anode and bromide ions at the cathode.

Bromine gas at the anode and lead metal at the cathode.

Hydrogen gas at the cathode and oxygen gas at the anode.

Lead metal at the anode and bromine gas at the cathode.

None

What happens to the electrons at the positive terminal (cathode) of a simple chemical cell, such as one made of zinc and copper?

They are accepted by positive ions from the electrolyte.

They are released by the copper electrode into the solution.

They combine with the atoms of the cathode material.

They flow from the cathode to the anode through the external wire.

None

In a simple chemical cell constructed with magnesium and copper electrodes in an electrolyte, why does the magnesium strip become thinner over time?

The magnesium strip physically flakes off due to the electric current.

Copper ions from the solution deposit onto the magnesium strip.

Electrons from the copper strip react with the magnesium.

Magnesium atoms lose electrons to become magnesium ions.

None

What is the primary function of adding cryolite (Na3AlF6) to aluminium oxide (Al2O3) during the industrial extraction of aluminium?

To act as a catalyst and speed up the reaction.

To increase the purity of the final aluminium product.

To prevent the carbon anodes from oxidizing.

To significantly lower the melting point of aluminium oxide.

None

A chemical reaction has a change in enthalpy value of ΔH=−1204 kJ mol−1. Which statement accurately describes this reaction?

The products have a higher energy content than the reactants.

The reaction is endothermic, absorbing heat from the surroundings.

The reaction is exothermic, releasing heat into the surroundings.

The surroundings would feel colder as the reaction proceeds.

None

Which of the following reaction equations represents an endothermic process?

C+2S→CS 2 ΔH=+320 kJ mol−1

C2H5OH + 3O2 →2CO2 + 3H2O ΔH = −1270 kJ mol−1

2Mg + O2 →2MgO ΔH = −1204 kJ mol−1

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

None

In the industrial process of purifying copper, what is the role of the impure copper block?

It acts as the anode, which dissolves during electrolysis

It functions as the electrolyte for the cell

It is used to stir the electrolyte solution.

It serves as the cathode, where pure copper is deposited.

None

In a photochromic lens, what causes the glass to darken upon exposure to sunlight?

The glass undergoes a permanent chemical change

The glass absorbs light and then releases it as heat.

A heat-sensitive dye embedded in the glass changes color

Silver halide crystals decompose into dark silver particles.

None

Why are photosensitive chemicals such as silver bromide and hydrogen peroxide typically stored in dark or opaque bottles?

To prevent them from evaporating quickly.

To prevent chemical reactions with the glass container.

To protect them from decomposition caused by light.

To keep the chemicals at a constant cool temperature.

None

10.

What is the specific process that uses light energy to split water molecules into hydrogen ions and oxygen during photosynthesis?

Photolysis

Hydrolysis

Electrolysis

Photosynthesis

None

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