IAL Chemistry Unit 1 The Mass Spectrometer

Welcome to your essential study guide on the mass spectrometer, a key topic for your IAL Chemistry Unit 1 exam. Use these notes to deepen your understanding and prepare effectively.

Uses of the Mass Spectrometer

The mass spectrometer is a vital instrument used to accurately calculate the reactive atomic mass. It measures the mass of each isotope of an element and compares their relative abundance. Key applications include:

• Carbon Dating: Determining the age of archaeological finds.
• Blood Alcohol Measurement: Analyzing alcohol levels in forensic science.
• Pharmaceutical Purity Testing: Ensuring the quality and purity of drugs.
• Molecular Mass and Structure Determination: Identifying molecular composition and structure.

Separation of Isotopes

The mass spectrometer separates isotopes through the following steps:

1. Vaporisation:
   • The sample is heated to convert it into a gaseous state, allowing it to flow into the device.
2. Ionisation:
   • The vaporised sample is bombarded with high-energy electrons, knocking out electrons from atoms and forming cations (mostly 1+).
3. Acceleration:
   • Cations are accelerated by an electric field to ensure they have uniform speed.
4. Deflection:
   • A magnetic field deflects the accelerated cations based on their mass-to-charge ratio.
   • Heavier ions deflect less, while ions with higher charges deflect more.
5. Detection:
   • Ions are detected on a fluorescent screen, and the mass spectrum is displayed on a computer screen as a graph.

Important Considerations

• The entire process occurs under vacuum conditions to prevent ions from colliding with air particles, ensuring accurate measurements.

These notes are designed to help you grasp the fundamental concepts and processes related to the mass spectrometer, crucial for your Unit 1 exam. Make sure to review these regularly, and best of luck with your studies!