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

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

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.

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

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

None

Which of the following reaction equations represents an endothermic process?

2Mg + O2 →2MgO ΔH = −1204 kJ mol−1

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

C+2S→CS 2 ΔH=+320 kJ mol−1

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

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.

Both the anode and cathode are made of iron.

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

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

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 endothermic, absorbing heat from the surroundings.

The reaction is exothermic, releasing heat into the surroundings.

The surroundings would feel colder as the reaction proceeds.

The products have a higher energy content than the reactants.

None

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 chemical reactions with the glass container.

To protect them from decomposition caused by light.

To prevent them from evaporating quickly.

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.

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.

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 significantly lower the melting point of aluminium oxide.

To prevent the carbon anodes from oxidizing.

To increase the purity of the final aluminium product.

None

Which energy transformation occurs in an electrolytic cell?

Electrical energy to chemical energy

Chemical energy to electrical energy

Heat energy to electrical energy

Light energy to chemical energy

None

10.

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

Oxygen

Chlorine

Sodium

Hydrogen

None

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