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LC Chemistry
LC Chemistry
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LC Chemistry

All Chemistry Definitions to Learn for Leaving Certificate - Higher Level

The Atom

  • Dalton’s Atomic Theory: All matter is made up of indivisible atoms which cannot be created or destroyed.
  • William Crookes discovered the Electron. Cathode ray tube.
  • JJ Thomson determined that electrons were negative. Found E/M ratio.
  • Robert Millikan’s Oil drop experiment discovered size of electron’s charge.
  • Plum Pudding Model: Solid positive sphere with electrons embedded.
  • Rutherford discovered the Nucleus. Fired alpha particles at gold foil. Proton.
  • Chadwick discovered the neutron by firing alpha particles at beryllium.
  • Energy level is the fixed energy value that an electron in an atom may have.
  • Heisenberg’s Uncertainty Principle states that it is... (More)
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LC Chemistry

Preparing a Standard Solution of Sodium Carbonate

Weigh the sample

  • Weigh 1.30 g of sodium carbonate on an electronic balance, as accurately as you can. Use a clock glass.
  • Two places of decimals would be best.

Transfer to beaker

  • Use a spatula to transfer the sample to a beaker of warm water (100ml).
  • Rinse the clock glass.
  • Rinse the remaining grains into the beaker with deionised water.
  • Rinse the spatula into the beaker also.
  • All traces must be transferred.

Pour the washings into the volumetric flask.

  • Pour the washings into the volumetric flask, using a funnel and a glass rod.
  • Wash the rod as well.
  • Rinse the... (More)
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LC Chemistry

Organic Chemistry – Summary

General Definitions

  • Organic Chemistry is the study of compounds of Carbon.
  • Hydrocarbons are carbons consisting of carbon and hydrogen only, bonded together covalently. They are used as fuel and feedstock for the chemical industry. Main Sources: Coal, Methane, Crude Oil.
  • Structural isomers are compounds that have the same molecular formula but different structural formulas.

Homologous Series is defined as:

  1. A series of compounds of uniform chemical type.
  2. Showing gradations in physical properties.
  3. Having a general formula for its members.
  4. Each member having similar chemical properties & preparation.
  5. Each member differing from the previous by a CH2 unit.... (More)
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LC Chemistry

The Atom

Matter is composed of very small particles which may be atoms, molecules or ions.

The History of the Atom

The Greek philosophers first proposed that there were indivisible particles which they called ‘atoms’ which means ‘indivisible’ in Greek. This is where we get the word atom.

John Dalton

In 1808, an English chemist called John Dalton was able to provide indirect evidence for the existence of atoms.

Dalton’s Atomic Theory:

  1. All matter is made up of very small particles called atoms.
  2. All atoms are indivisible. They cannot be broken down into simpler particles.
  3. Atoms cannot be created or destroyed.... (More)