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

Which energy transformation occurs in an electrolytic cell?

Chemical energy to electrical energy

Heat energy to electrical energy

Electrical energy to chemical energy

Light energy to chemical energy

None

In the industrial process of purifying copper, what is the role of the impure copper block?

It serves as the cathode, where pure copper is deposited.

It acts as the anode, which dissolves during electrolysis

It is used to stir the electrolyte solution.

It functions as the electrolyte for the cell

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 surroundings would feel colder as the reaction proceeds.

The products have a higher energy content than the reactants.

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?

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

Magnesium atoms lose electrons to become magnesium ions.

Electrons from the copper strip react with the magnesium.

Copper ions from the solution deposit onto the magnesium strip.

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 keep the chemicals at a constant cool temperature.

To protect them from decomposition caused by light.

To prevent them from evaporating quickly.

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 combine with the atoms of the cathode material.

They are accepted by positive ions from the electrolyte.

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

They are released by the copper electrode into the solution.

None

Which of the following reaction equations represents an endothermic process?

Zn+2HCl→ZnCl2 +H2 ΔH = −152 kJ mol−1

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

None

What is the primary function of adding cryolite (Na3AlF6) to aluminium oxide (Al2O3) during the industrial extraction of aluminium?

To significantly lower the melting point of aluminium oxide.

To act as a catalyst and speed up the reaction.

To prevent the carbon anodes from oxidizing.

To increase the purity of the final aluminium product.

None

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

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

None

10.

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

The glass undergoes a permanent chemical change

The glass absorbs light and then releases it as heat.

A heat-sensitive dye embedded in the glass changes color

Silver halide crystals decompose into dark silver particles.

None

1 out of 10