UNIT 2 DEFINITIONS AND RECALL Flashcards
Isotopes
Atoms of the same element with same number of protons and electrons but different number of neutrons.
Relative atomic mass, RAM (or Ar)
Average mass of an atom relative to 1/12th the mass of one
atom of 12C ✓
Relative isotopic mass
Relative isotopic mass – Mass of the isotope compared to 1/12th the mass of a 12C atom ✓
Weighted mean mass
Weighted mean mass – Mean mass taking into account the relative abundancies of the
isotopes✓
Preparing a standard solution - how ?
Preparing a standard solution
Dissolve ____ g of the solid in distilled water in a beaker ✓
Transfer the solution to a 250 cm3 volumetric flask ✓
Ensure that all solution is washed out of beaker ✓
Make solution up to 250 cm3 with distilled water ✓
Ensure thorough mixing by inverting the flask several times ✓
Limiting reagent
A reagent which limits the progress of a reaction is known as a limiting reagent.
Factors affecting yield
- The reaction may not go to completion ✓
- The reactants may not be pure. ✓
- Other reactions may occur which lead to by-products. ✓
- Products may be left behind in the reaction vessel. ✓
- Separation and purification of the product may result in loss of some of the product. ✓
Empirical Formula
Empirical Formula – The simplest whole number ratio of atoms present in a compound ✓
Molecular formula
Molecular formula – The actual number of atoms of each element in a molecule ✓
Hydrated salts:
Anhydrous salts:
Hydrated salts: contains water of crystallisation
Anhydrous salts: contains no water of crystallisation
Brønsted–Lowry Acids
Brønsted–Lowry Acids
Acid – Proton donor ✓
Brønsted–Lowry Bases
Brønsted–Lowry Bases
Base – Proton acceptor ✓
Alkali
Alkali – Releases OH- ions into solution ✓
Acid + Metal → Salt + Hydrogen ✓
(observations )
Fizzing ✓
Solid dissolves ✓
Acid + Metal oxide → Salt + Water ✓
Solid dissolves.
