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

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

The glass absorbs light and then releases it as heat.

Silver halide crystals decompose into dark silver particles.

The glass undergoes a permanent chemical change

A heat-sensitive dye embedded in the glass changes color

None

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

To prevent chemical reactions with the glass container.

To protect them from decomposition caused by light.

To prevent them from evaporating quickly.

To keep the chemicals at a constant cool temperature.

None

Which of the following reaction equations represents an endothermic process?

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

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

2Mg + O2 →2MgO ΔH = −1204 kJ mol−1

C+2S→CS 2 ΔH=+320 kJ mol−1

None

When electroplating an iron spoon with copper, which of the following setups is correct?

Both the anode and cathode are made of iron.

The electrolyte is a solution of iron(II) sulfate.

The iron spoon is the anode, and a copper bar is the cathode.

The iron spoon is the cathode, and the electrolyte is copper(II) sulfate.

None

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 is less reactive than glass with the chemical solutions.

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

Plastic is transparent, allowing for better observation.

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

None

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

None

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

The reaction is exothermic, releasing heat into the surroundings.

The products have a higher energy content than the reactants.

The surroundings would feel colder as the reaction proceeds.

The reaction is endothermic, absorbing heat from the surroundings.

None

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

Copper ions from the solution deposit onto the magnesium strip.

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

Electrons from the copper strip react with the magnesium.

Magnesium atoms lose electrons to become magnesium ions.

None

Which energy transformation occurs in an electrolytic cell?

Heat energy to electrical energy

Chemical energy to electrical energy

Electrical energy to chemical energy

Light energy to chemical energy

None

10.

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.

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

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

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

None

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