Chapter 14: Properties of Metals

Which substances react to form hydrogen gas? Choose the correct combination.

• 1, 3 and 4

• 1 and 3 only

• 2 and 4

• 4 only

Answer explanation

Substances 1, 3, and 4 react with acids or other reactants to produce hydrogen gas. Therefore, the correct combination that forms hydrogen gas is 1, 3, and 4.

Which gas is produced when powdered zinc is added to dilute hydrochloric acid?

• carbon dioxide

• chlorine

• hydrogen

• oxygen

Answer explanation

When powdered zinc reacts with dilute hydrochloric acid, it produces hydrogen gas as a byproduct. The reaction can be represented by the equation: Zn + 2HCl → ZnCl2 + H2, confirming that hydrogen is the correct answer.

Solid P reacts with dilute acids and also conducts electricity. Three students suggest identities for P: X says copper, Y says iron, Z says graphite. Which students are correct?

• X, Y and Z

• X only

• Y only

• Z only

Answer explanation

Iron (Y) reacts with dilute acids and conducts electricity, making it the correct choice. Copper (X) does not react with dilute acids, and graphite (Z), while a conductor, does not react with acids.

A table shows melting point and electrical conductivity (solid and molten) for four substances. Which row describes a non‑metallic element?

• 63°C; good (solid); good (molten)

• 119°C; poor (solid); poor (molten)

• 659°C; good (solid); good (molten)

• 808°C; poor (solid); good (molten)

Answer explanation

The row '119°C; poor (solid); poor (molten)' indicates a non-metallic element, as non-metals typically have lower melting points and poor electrical conductivity in both solid and molten states.

Which property is true of all metals?

• conducts electricity

• hard

• low melting point

• reacts with water

Answer explanation

All metals conduct electricity due to the presence of free-moving electrons. While some metals are hard and others have varying melting points, not all metals react with water. Therefore, the ability to conduct electricity is a universal property of metals.

A metal reacts vigorously with cold water. Which statement about the metal is correct?

• It is above hydrogen in the reactivity series.

• It is below magnesium in the reactivity series.

• Its oxide can be reduced with carbon.

• It does not react with dilute acids.

Answer explanation

The metal's vigorous reaction with cold water indicates it is highly reactive. Metals that react with water are above hydrogen in the reactivity series, confirming that the correct statement is that it is above hydrogen.

Which statements about general properties of metals are correct? 1 They are good conductors of heat and electricity. 2 They have low melting points. 3 They react with dilute acids to form a salt and water. 4 They react with oxygen to form basic oxides.

• 1 and 2

• 1 and 4

• 2 and 3

• 3 and 4

Answer explanation

Metals are good conductors of heat and electricity (1) and react with oxygen to form basic oxides (4). They typically have high melting points, not low (2), and while they react with acids, this is not universally true for all metals (3).

The diagram shows an experiment with a funnel delivering aqueous P onto solid Q in a flask connected to a syringe. Which pairs of substances cause the syringe to fill with gas?

• HNO3 and Mg; HCl and Cu; H2SO4 and Na2CO3 all produce gas

• HNO3 and Mg and HCl and Cu produce gas; H2SO4 and Na2CO3 does not

• HNO3 and Mg produces gas; HCl and Cu does not; H2SO4 and Na2CO3 produces gas

• HNO3 and Mg does not produce gas; HCl and Cu and H2SO4 and Na2CO3 produce gas

Answer explanation

HNO3 and Mg react to produce hydrogen gas, while HCl and Cu do not produce gas. H2SO4 and Na2CO3 react to produce carbon dioxide gas. Thus, the correct choice is that HNO3 and Mg produces gas; HCl and Cu does not; H2SO4 and Na2CO3 produces gas.

Which statement about metals is not correct?

• They conduct electricity because delocalised electrons can move throughout the metal.

• They consist of layers of atoms that can slide over each other.

• They have a giant lattice of oppositely charged ions in a ‘sea’ of delocalised electrons.

• They have a giant lattice of positive ions in a ‘sea’ of delocalised electrons.

Answer explanation

The statement 'They have a giant lattice of oppositely charged ions in a ‘sea’ of delocalised electrons' is incorrect because metals consist of a lattice of positive ions, not oppositely charged ions.