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

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

To keep the chemicals at a constant cool temperature.

To protect them from decomposition caused by light.

To prevent them from evaporating quickly.

To prevent chemical reactions with the glass container.

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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 exothermic, releasing heat into the surroundings.

The reaction is endothermic, absorbing heat from the surroundings.

The surroundings would feel colder as the reaction proceeds.

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During the electrolysis of a dilute aqueous sodium chloride (NaCl) solution using inert electrodes, what gas is produced at the anode?

Chlorine

Hydrogen

Sodium

Oxygen

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In an experiment to measure the heat of displacement, a plastic cup is used as the calorimeter. What is the main reason for this choice?

Plastic cups are cheaper and more readily available than glass beakers.

Plastic is less reactive than glass with the chemical solutions.

Plastic is transparent, allowing for better observation.

Plastic is a good insulator, minimizing heat loss to the surroundings.

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

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

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

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

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

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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 serves as the cathode, where pure copper is deposited.

It functions as the electrolyte for the cell

It is used to stir the electrolyte solution.

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Which energy transformation occurs in an electrolytic cell?

Light energy to chemical energy

Chemical energy to electrical energy

Electrical energy to chemical energy

Heat energy to electrical energy

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

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

They are released by the copper electrode into the solution.

They are accepted by positive ions from the electrolyte.

They combine with the atoms of the cathode material.

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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.

Magnesium atoms lose electrons to become magnesium ions.

Copper ions from the solution deposit onto the magnesium strip.

Electrons from the copper strip react with the magnesium.

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10.

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

Silver halide crystals decompose into dark silver particles.

A heat-sensitive dye embedded in the glass changes color

The glass undergoes a permanent chemical change

The glass absorbs light and then releases it as heat.

None

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