principles of chemistry

• States of matter:

  • Three states of matter: solid, liquid, gas
  • Arrangement, movement, and energy of particles differ in each state
• Interconversions between states of matter involve:

  • Names of interconversions
  • How they are achieved
  • Changes in arrangement, movement, and energy of particles
• Experiments involving dilution of coloured solutions and diffusion of gases can explain results
• Terms to know:

  • Solvent: substance that dissolves a solute
  • Solute: substance dissolved in a solvent
  • Solution: homogeneous mixture of solvent and solute
  • Saturated solution: a solution containing the maximum amount of solute that can be dissolved
• Classification of substances:

  • Element: pure substance with fixed melting and boiling points
  • Compound: pure substance with fixed melting and boiling points
  • Mixture: may melt or boil over a range of temperatures
• Experimental techniques for separation of mixtures:

  • Simple distillation
  • Fractional distillation
  • Filtration
  • Crystallisation
  • Paper chromatography
• Chromatogram provides information about mixture composition
• Calculation of Rf values helps identify components of a mixture
• Investigate paper chromatography using inks/food colourings practically
• Atomic structure:

  • Atom: basic unit of matter
  • Molecule: group of atoms bonded together
  • Structure of an atom: positions, relative masses, relative charges of sub-atomic particles
• Terms to know:

  • Atomic number
  • Mass number
  • Isotopes
  • Relative atomic mass (Ar)
• Periodic Table:

  • Elements arranged by atomic number, in groups and periods
  • Electronic configurations deduced from positions in the Periodic Table
  • Classification of elements as metals or non-metals based on electrical conductivity and acid-base character of oxides
• Elements in the same group have similar chemical properties
• Noble gases (Group 0) do not readily react
• Chemical formulae, equations, and calculations:

  • Writing word equations and balanced chemical equations
  • Calculating relative formula masses (Mr) from relative atomic masses (Ar)
  • Mole (mol) as the unit for the amount of a substance
• Calculating reacting masses, percentage yield, empirical and molecular formulae
• Determining the formula of a metal oxide practically
• Ionic bonding:

  • Ions formed by electron loss or gain
  • Charges of ions listed
  • Formation of ionic compounds by electron transfer
  • Ionic bonding in terms of electrostatic attractions
• Compounds with giant ionic lattices have high melting and boiling points
• Covalent bonding:

  • Covalent bond formed by sharing a pair of electrons
  • Dot-and-cross diagrams represent covalent bonds
  • Explanation of substances with simple molecular structures and giant covalent structures
• Physical properties of diamond, graphite, and C60 fullerene influenced by their structures
• Covalent compounds do not usually conduct electricity
• The periodic table is organized by atomic number, which determines the number of protons in an atom.
• Metals tend to be found at the left side of the periodic table, while nonmetals are located towards the right.