S1.1 Particulate nature of matter

Which is not an element?

• krypton

• water

• silver

• mercury

Which is an example of a homogeneous mixture?

• sugar solution

• sand

• sea water

• oil and water

Which is a mixture?

• washing soda crystals, Na₂CO₃ • 10H₂O

• water

• air

• carbon dioxide

Sodium is a metal and chlorine is a green non-metal. They react together to form sodium chloride, NaCl. What can be deduced correctly about the physical properties of solid sodium chloride?

• Its melting point will be different to the melting points of sodium and chlorine.

• It will be green.

• It will be a semi-metal (metalloid).

• It will conduct electricity .

Which of the following is an element?

• air

• methane

• ozone

• ice

Which mixture can best be separated into its separate components by using chromatography?

• sea-water

• black ink

• sodium hydroxide solution

• air

Which reaction involves precipitation?

• NaOH(aq) + H₂SO₄(aq) ⟶ Na₂SO₄(aq) + H2O(l)

• AgNO₃(aq) + NaCl(aq) ⟶ AgCl(s) + NaNO₃(aq)

• CaCO₃(s) + 2HCl(aq) ⟶ CaCl₂(aq) + H₂O(l) + CO₂(g)

• Fe(s) + S(s) ⟶ FeS(s)

Argon, carbon dioxide, oxygen and nitrogen are all present in air. What is the order in which the gases will be formed when liquid air is slowly warmed?

• CO₂ > O₂ > Ar > N₂

• N₂ > Ar > O₂ > CO₂

• N₂ > O₂ > Ar > CO₂

• CO₂ > Ar > O₂ > N₂

At high altitude snow can sublime. Which statement correctly describes this process?

• Snow turns into liquid water.

• Snow forms hard ice.

• Snow turns into liquid water which then turns into water vapour.

• Snow turns directly into water vapour.

Which of the following statements are correct about reflux?

• It allows a reaction to proceed without losing the reactants or solvent through evaporation or boiling.

• It increases the rate of the reaction.

• Volatile products may be separated and collected during the process.