AS Chemistry Assessment 1 Revision

Which atom has the greatest first ionisation energy?

• H

• He

• Li

• Ne

When He²⁺ particles were fired at a thin sheet of gold, about 1 in 8000 of the particles were detected at point Q. What conclusion can be drawn from the detection of He²⁺ particles at point Q?

• Gold atoms have a small, positive nucleus.

• Gold atoms have electrons in orbitals.

• Gold consists of ions in a sea of delocalised electrons.

• Gold atoms have more protons than He²⁺ particles.

Which statement about time of flight mass spectrometry is correct?

• The current in the detector is proportional to the ion abundance

• Sample particles gain electrons to form positive ions

• Particles are detected in the order of their kinetic energies

• Ions are accelerated by a magnetic field

Chlorine exists as two isotopes ³⁵Cl and ³⁷Cl in the ratio 3:1

Which statement about peaks in the mass spectrum of Cl₂ is correct?

• Peaks at m/z = 70 and 74 in the ratio 3:1

• Peaks at m/z = 70, 72 and 74 in the ratio 9:6:1

• Peaks at m/z = 70, 72 and 74 in the ratio 9:3:1

• Peaks at m/z = 70 and 72 in the ratio 3:1

What is the electron configuration of Cu²⁺?

• [Ar]3d⁹4s²

• [Ar]3d¹⁰4s¹

• [Ar]3d⁹

• [Ar]3d¹⁰

5.0 g of an oxide of molybdenum contain 4.0 g of molybdenum.

What is the empirical formula of this oxide?

• MoO₂

• Mo₄O₅

• Mo₂O₃

• Mo₃O₂

What is the percentage yield when 20 g of aluminium are produced from 50 g of aluminium oxide?

2Al₂O₃ → 4Al + 3O₂

• 76%

• 40%

• 33%

• 19%

A solution of volume 500 cm³ contains 150 g of ammonia.

What is the concentration, in mol dm^–3, of ammonia in this solution?

• 0.51

• 8.82

• 16.7

• 17.6

Which amount of sodium hydroxide would react exactly with 7.5 g of a diprotic acid, H₂A (M_r = 150)?

• 50 cm³ of 0.05 mol dm^–3 NaOH(aq)

• 100 cm³ of 0.50 mol dm^–3 NaOH(aq)

• 100 cm³ of 1.0 mol dm^–3 NaOH(aq)

• 100 cm³ of 2.0 mol dm^–3 NaOH(aq)

Which of these contains the greatest number of atoms?

• 127 mg of iodine

• 1.54 × 10⁻⁴ kg of phosphorus

• 81.0 mg of carbon dioxide

• 1.70 × 10⁻⁴ kg of ammonia