Dogs are loyal companions.

Chinese
狗是忠实的伴侣。

The sun rises every morning.

Chinese
太阳每天早上升起。

The sun rises every morning. Chinese太阳每天早上升起。

What is the sub-atomic particle with the smallest relative mass?

The sub-atomic particle with the smallest relative mass is the electron.

Explain why atoms have the same number of protons as electrons.

Atoms have the same number of protons as electrons because of electrical neutrality. Protons carry a positive charge, while electrons carry a negative charge. In an electrically neutral atom, the number of protons (which have a positive charge) equals the number of electrons (which have a negative charge), resulting in a balance of charges. This balance ensures that the overall charge of the atom is neutral.

An aluminium atom can be represented as $_{13}^{27}$Al.

Identify aluminium’s mass number.

The notation $_{13}^{27}$Al represents an aluminium atom with a mass number of 27. The number 27 is the sum of protons and neutrons in the nucleus of the atom.

Calculate how many neutrons this atom of aluminium has.

To calculate the number of neutrons, subtract the atomic number (which represents the number of protons) from the mass number:

Number of neutrons = Mass number – Atomic number

For aluminium:
Atomic number (Z) = 13
Mass number (A) = 27

Number of neutrons = 27 – 13 = 14

Therefore, this atom of aluminium has 14 neutrons.

What does the bonding in iron consist of?

Iron consists of positive ions in a sea of delocalized electrons.

How do electrons contribute to iron’s ability to conduct electricity?

Electrons in iron are free to move, allowing electrical conduction.

What causes alloys like steel to be harder and stronger than pure iron?

Atoms of different sizes prevent the layers from sliding easily over each other.

What are the substances that react with iron to form rust?

Oxygen and water.

What is the process called where zinc is used to coat iron to prevent rusting?

Galvanising.

How does the zinc coating protect iron from rusting?

Zinc acts as a barrier to prevent oxygen and water from reaching iron.

How does zinc continue to protect iron from rusting even if the coating is scratched?

Zinc is more reactive than iron and continues to oxidize preferentially, protecting the iron.

What is the role of coke in the extraction of iron in a blast furnace?

Coke releases heat, reduces iron(III) oxide, and reacts with carbon dioxide to form carbon monoxide.

What happens when limestone decomposes in the blast furnace?

Limestone decomposes to calcium oxide, which reacts with silicon(IV) oxide to form slag.

Why is the temperature in the furnace maintained above the melting point of iron?

To keep iron molten, allowing it to separate from the slag.

What is the main chemical reaction of iron extraction in the blast furnace?

Fe₂O₃ + 3CO → 2Fe + 3CO₂.

Why is it important to have different atom sizes in an alloy?

Prevents the layers of atoms from sliding over each other, enhancing strength.

How does coke contribute to the reduction of iron ore?

Coke acts as a reducing agent by donating electrons to iron(III) oxide, reducing it to iron.

What is the purpose of adding limestone to the iron extraction process?

To remove impurities by forming slag with silicon(IV) oxide.

What chemical process occurs when zinc is exposed and iron is protected?

Zinc oxidizes by losing electrons, protecting iron through sacrificial protection.

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