Chemistry Grade 9 Quiz

Which statement about gases is CORRECT?

• Gases are difficult to compress when pressure is applied.

• The particles in gases are close together.

• The particles in gases have a random arrangement.

• The particles in gases move slowly past each other.

The statements describe TWO changes of state.

1. The molecules of substance X are arranged randomly. During the change of state, they lose energy and become more ordered. The molecules can still move freely.

2. The molecules of substance Y are arranged in a regular lattice. During the change of state, they gain energy and become less ordered. The molecules are still close together.

Which changes of state are described by the statements?

• 1 condensation, 2 evaporation

• 1 condensation, 2 melting

• 1 freezing, 2 evaporation

• 1 freezing, 2 melting

A beaker containing solid carbon dioxide is placed in a fume cupboard at room temperature. The carbon dioxide becomes gaseous.
Which process describes this change of state?

• boiling

• condensation

• evaporation

• sublimation

1. When iodine is heated it turns from a solid to a gas.

2. When liquid ammonia is cooled it turns into a solid.

3. When ice is heated it turns into water.

Which term describe these changes of state?

• 1 Boiling, 2 Freezing, 3 Melting

• 1 Freezing, 2 Sublimation, 3 Boiling

• 1 Sublimation, 2 Condensation, 3 Freezing

• 1 Sublimation, 2 Freezing, 3 Melting

The melting points and boiling points of four elements are shown.

In which elements do the particles vibrate about fixed positions at 0°C?

• W and X

• W and Z

• X and Y

• Y and Z

A student prepares solid hydrated copper(II) sulfate from dilute sulfuric acid and the insoluble

base copper(II) oxide.

Which process is NOT used in the procedure?

• crystallisation

• distillation

• evaporation

• filtration

Salt is added to pure water to form an aqueous solution.

Which statement is CORRECT?

• The melting point and the boiling point of the water both decrease.

• The melting point and the boiling point of water both increase.

• The melting point of the water decreases but its boiling point increases.

• The melting point of the water increases but its boiling point decreases.

The chromatogram obtained from four mixtures of dyes, P, Q, R and S, is shown.

What is the total number of different dyes identified in the four mixtures?

• 3

• 4

• 5

• 8

Which of the statement about paper chromatography is correct?

• A solvent is needed to dissolve the paper.

• Paper chromatography separates mixtures of solvents.

• The solvent should cover the baseline.

• The baseline should be drawn in pencil.

Zinc sulfate is made by reacting an excess of zinc oxide with dilute sulfuric acid.

The excess zinc oxide is then removed from the solution.

Which process is used to obtain solid zinc sulfate from the solution?

• crystallisation

• dissolving

• filtration

• fractional distillation