AS Chemistry Definitions List Part 2

Question 1

Vacuum

Answer 1

High vacuum stops ions colliding with air molecules

Question 2

Ionisation

Answer 2

• Sample dissolved into volatile solvent and injected through a fine needle
• Needle is connected to +ve terminal through high voltage supply
• Electrons removed to form +ve ions
• Solvent evaporates and droplets get smaller until they contain a single +ve charged ion

Question 3

Acceleration

Answer 3

• +ve ions are accelerated forwards a -ve charged plate
• Lighter ions or more highly charged ions accelerate faster
• Heavy ions with less charge accelerate slower

Question 4

Ion drift

Answer 4

• Ions pass through a hole to form a beam of +ve ions that travel along the flight tube
• Lighter ions and more +ve charged particles move faster and have a shorter time of flight

Question 5

Detection

Answer 5

• Ions with the same charge and mass arrive at the detector at the same time
• Flight times are recorded
• At the detector +ve ions gain an electron and generate an electric current
• The size of the current is proportional to the relative abundance of each isotope or +ve ion

Question 6

Data analysis

Answer 6

• The size of current is used to produce a mass spectra showing the relative abundance of each +ve ion