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 prevent them from evaporating quickly.

To protect them from decomposition caused by light.

To prevent chemical reactions with the glass container.

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 reaction is endothermic, absorbing heat from the surroundings.

The products have a higher energy content than the reactants.

The surroundings would feel colder as the reaction proceeds.

None

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

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

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

Both the anode and cathode are made of iron.

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

None

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.

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

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

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

None

Which of the following reaction equations represents an endothermic process?

C+2S→CS 2 ΔH=+320 kJ mol−1

2Mg + O2 →2MgO ΔH = −1204 kJ mol−1

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

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

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 released by the copper electrode into the solution.

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

They combine with the atoms of the cathode material.

They are accepted by positive ions from the electrolyte.

None

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

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

The glass absorbs light and then releases it as heat.

None

Which energy transformation occurs in an electrolytic cell?

Heat energy to electrical energy

Light energy to chemical energy

Chemical energy to electrical energy

Electrical energy to chemical energy

None

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

Oxygen

Sodium

Hydrogen

Chlorine

None

10.

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 a good insulator, minimizing heat loss to the surroundings.

Plastic is less reactive than glass with the chemical solutions.

Plastic is transparent, allowing for better observation.

None

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