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.

A heat-sensitive dye embedded in the glass changes color

The glass undergoes a permanent chemical change

Silver halide crystals decompose into dark silver particles.

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

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 surroundings would feel colder as the reaction proceeds.

The products have a higher energy content than the reactants.

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

To increase the purity of the final aluminium product.

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.

None

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

It is used to stir the electrolyte solution.

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

It acts as the anode, which dissolves during electrolysis

It functions as the electrolyte for the cell

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

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

Hydrogen

Chlorine

Oxygen

Sodium

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

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 is transparent, allowing for better observation.

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

Plastic is less reactive than glass with the chemical solutions.

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

None

1 out of 10