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.

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

They combine with the atoms of the cathode material.

They are released by the copper electrode into the solution.

They are accepted by positive ions from the electrolyte.

None

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

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

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

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

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

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 transparent, allowing for better observation.

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.

None

Which of the following reaction equations represents an endothermic process?

2Mg + O2 →2MgO ΔH = −1204 kJ mol−1

C+2S→CS 2 ΔH=+320 kJ mol−1

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

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

None

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

Magnesium atoms lose electrons to become magnesium ions.

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.

None

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

Which energy transformation occurs in an electrolytic cell?

Light energy to chemical energy

Heat energy to electrical energy

Electrical energy to chemical energy

Chemical energy to electrical energy

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 exothermic, releasing heat into the surroundings.

The reaction is endothermic, absorbing heat from the surroundings.

The surroundings would feel colder as the reaction proceeds.

None

10.

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

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

Both the anode and cathode are made of iron.

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

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