Chapter 2 Practice Paper: States of matter, mixtures and separation — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   A substance has a melting point of 63 °C and a boiling point of 768 °C. At 500 °C the substance is a

   1. Asolid
   2. Bliquid
   3. Cgas
   4. Dmixture of liquid and gas
   ( )
2. 2

   Which change of state takes energy in from the surroundings?

   1. AFreezing
   2. BCondensing
   3. CMelting
   4. DSolidifying
   ( )
3. 3

   The particles in a liquid, compared with those in a gas, are

   1. Acloser together and slower
   2. Bfurther apart and faster
   3. Cthe same distance apart but slower
   4. Dsmaller and heavier
   ( )
4. 4

   A pure substance melts

   1. Aover a range of temperatures
   2. Bonly above 100 °C
   3. Cfaster than a mixture
   4. Dat one fixed temperature
   ( )
5. 5

   Which product is a formulation?

   1. AOxygen gas
   2. BSunflower oil
   3. CA pain-relief tablet
   4. DA copper wire
   ( )
6. 6

   The best technique for obtaining drinking water from salty well water is

   1. Afiltration
   2. Bsimple distillation
   3. Ccrystallisation
   4. Dchromatography
   ( )
7. 7

   In fractional distillation of crude oil, fractions with the highest boiling points condense

   1. Anear the hot bottom of the tower
   2. Bat the top of the tower
   3. Coutside the tower
   4. Donly in the condenser
   ( )
8. 8

   Which pair correctly matches the phases in paper chromatography?

   	Stationary phase	Mobile phase
   A	solvent	paper
   B	paper	solvent
   C	tank	paper
   D	pencil line	tank air
9. 9

   Dissolved blue copper sulfate cannot be removed from its solution by filtration because

   1. Acopper sulfate is too dense
   2. Bthe solution is too hot
   3. Ccopper sulfate reacts with paper
   4. Dthe dissolved particles pass through the filter paper pores
   ( )
10. 10

    During boiling at atmospheric pressure, the temperature of a pure liquid

    1. Arises steadily
    2. Bfalls slowly
    3. Cstays constant at the boiling point
    4. Doscillates around the boiling point
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   Propanone is a colourless liquid used as nail-varnish remover. It melts at −95 °C and boils at 56 °C.

   1. (a)

      State the physical state of propanone at 25 °C. Give a reason.

      [1]
   2. (b)

      Propanone is poured onto a warm palm and soon disappears. Name the change of state and state what happens to the particles.

      [2]
   3. (c)

      Explain why propanone feels cold as it evaporates from skin.

      [2]
2. 12

   A student wants pure dry zinc sulfate crystals from a lumpy mixture of zinc sulfate solid and insoluble sand.

   1. (a)

      Describe the full procedure, naming each technique and why it is used.

      [4]
   2. (b)

      The student boils the solution to complete dryness instead. State two things that could go wrong.

      [2]
   3. (c)

      State one observation that would show the filtrate is still a solution and not pure water.

      [1]
3. 13

   A black ink is analysed by paper chromatography. Three reference dyes are run beside it. The solvent front rises 10 cm.

   Distances moved from the start line

   Spot	Distance moved
   Reference red	2 cm
   Reference blue	5 cm
   Reference yellow	8 cm
   Ink spot 1	2 cm
   Ink spot 2	5 cm
   Ink spot 3	6.5 cm

   1. (a)

      Identify the dyes present in the ink. Justify your answer.

      [2]
   2. (b)

      Explain why the yellow reference rises higher than the red reference.

      [2]
   3. (c)

      State why the chromatogram shows the ink is a mixture, not a pure dye.

      [1]
   4. (d)

      Explain one reason the solvent front must be marked before the paper dries.

      [1]
   5. (e)

      The baseline was drawn in biro in a second attempt. Explain the problem this causes.

      [2]