Paper 1 Exam Questions

Question 1

Why did Mendeleev’s periodic table become more widely accepted than previous versions? (3 marks)

Answer 1

• Mendeleev had predicted
  properties of missing elements
• elements were discovered (that
  filled the spaces / gaps)
• properties (of these elements)
  matched Mendeleev’s
  predictions

Question 2

Evidence from the alpha particle scattering experiment led to a change in the model of the atom from the plum pudding model. Explain how. (4 marks)

Answer 2

• most (alpha) particles passed
  (straight) through (the gold foil)
• (so) the mass of the atom is
  concentrated in the nucleus /
  centre
• some (alpha) particles were
  deflected / reflected
• (so) the atom has a (positively)
  charged nucleus / centre

Question 3

A newspaper article referred to trains converted from diesel to hydrogen fuel cells as the new ‘steam trains’. Suggest why. (2 marks)

Answer 3

• (in a fuel cell) hydrogen is
  oxidised (to produce water)
• water is produced / released as
  gas / vapour / steam

Question 4

In moles = mass / mr, what unit is mass in?

Answer 4

grams

Question 5

In a reaction, explain why excess hydrogen must be burned off. (2 marks)

Answer 5

• to prevent hydrogen escaping
  (into the air)
• (because) hydrogen is explosive

Question 6

Suggest why the student used a polystyrene cup rather than a glass beaker in a temperature based reaction. (2 marks)

Answer 6

• polystyrene is a better (thermal)
  insulator
• (so) reduces energy exchange
  (with the surroundings)

Question 7

Why can alkaline batteries not be recharged? (1 marks)

Answer 7

The reaction is not reversible

Question 8

The student’s results are used to place copper, iron, magnesium and zinc in order of their reactivity.

Describe a method to find the position of an unknown metal in this reactivity series.

Your method should give valid results.
[4 marks]

Answer 8

• add the unknown metal to copper sulfate solution
• measure temperature change
• place the metals in order of temperature change
• any named control variable, e.g same volume of solution

Question 9

Titanium chloride is a liquid at room temperature.

Explain why you would not expect titanium chloride to be a liquid at room temperature. (3 marks)

Answer 9

• metal chlorides are usually ionic
• (so)(metal chlorides) are solid at
  room temperature
• (because) they have strong
  (electrostatic) forces between
  the ions
• (but) must be a small molecule
  or covalent

Question 10

Explain why the student should use a pipette to measure the dilute sulfuric acid and a burette to measure the sodium hydroxide solution. (2 marks)

Answer 10

• pipette measures a fixed volume
  (accurately)
• (but) burette measures variable
  volume