AS Chemistry

AS Chemistry

1. Atomic Structure

   • Isotopes are the same element (same atomic number0 with a different number of neutrons within its nucleus, hence giving it a different mass
   • Mass Spectrometry
     • Used to find the mass and abundance of each isotope in an element allowing the Ar to be calculated
     • Steps: Ionisation, Acceleration, Drift Region, Detection
       • Mass Spec Graphs and Calculations
     • Also helps identify molecules by determining their Mr e.g. testing athete's blood for illegal substances
   • Calculations and Definitions
     • Mass Number: the total number of protons and neutrons in the nucleus of one atom of the element
     • Atomic Number: The number of protons in the nucleus of an atom
   • Electron Configuration
     • First Ionisation Energy: the enthalpy change when one mole of electrons is removed from one mole of gaseous atoms of an element
     • Down a group the IA decreases due to DNS, across a group the IA increases due to increased nuclear charge with the same/similar shielding

2. Bonding

3. Energetics

4. Amount of Substance

   • Ar= average mass per atom of an element/ 1/12 mass of 12C
   • Mr= average mass of a molecule/ 1/12 x mass of 12C
   • Moles= mass/Mr
   • Moles= conc. x vol
   • pV=nRT
   • %error= (error/reading)x100

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