GCSE Bonding, Structure and Properties of Matter (Chemistry) 2

Question 1

Which statement best describes metallic bonding?

Accepted Answer

A regular arrangement of positive metal ions surrounded by a sea of delocalised electrons

Answer

Metals consist of a giant structure of positive ions in a sea of delocalised electrons; the electrostatic attraction between them is the metallic bond.

Question 2

Why is an alloy such as brass harder than pure copper?

Accepted Answer

The different-sized atoms distort the layers, making it harder for them to slide over each other

Answer

In a pure metal the layers of identical atoms slide easily; in an alloy, atoms of different sizes disrupt the regular layers so they cannot slide as easily.

Question 3

A nanoparticle has a diameter of 50 nm. Which of these correctly expresses 50 nm in metres?

Accepted Answer

5 × 10⁻⁸ m

Answer

1 nm = 1 × 10⁻⁹ m, so 50 nm = 50 × 10⁻⁹ m = 5 × 10⁻⁸ m.

Question 4

Which change of state is called sublimation?

Accepted Answer

Solid directly to gas

Answer

Sublimation is when a solid turns directly into a gas without passing through the liquid state, as with solid carbon dioxide (dry ice).

Question 5

What is a limitation of the simple particle model used to describe solids, liquids and gases?

Accepted Answer

It assumes particles are solid, inelastic spheres with no forces between them

Answer

The simple model treats particles as small solid spheres and does not show the forces between them or that particles are not actually solid.

GCSE - General Certificate of Secondary Education Practice Test

GCSE - General Certificate of Secondary Education Practice Test

GCSE Bonding, Structure and Properties of Matter (Chemistry) 2