Chemistry

• explain why an ionic lattice has a high melting point

  Strong electrostatic attraction

  between oppositely charged ions

  requires a lot of energy to overcome forces
• explain why an ionic, compounds conduct, electricity when molten or dissolved, but not when solid?

  When molten or dissolved ions are free to move and carry charge
• describe the structure of an ionic lattice?

  giant ionic, lattice, regular arrangement of oppositely charged ions
• describe examples of simple, covalent molecules?


  Simple molecules contain only a few atoms held together by covalent bonds. An example is carbon dioxide which contains one atom of carbon bond with two atoms of oxygen.
• explain why simple molecules have a low boiling point or melting point?

  Weak, intermolecular forces between molecules, which require Little energy to overcome
• explain why carbon dioxide has a lower boiling point of water?

  Carbon dioxide has very weak. Intermolecular forces was a strong intermolecular forces between molecules called hydrogen bonds, which require more energy to be overcome.
• explain why graphite conduct, electricity, but diamond does not?

  Graphite has Delocalised electrons between layers which are free to move in Cary charge in diamond the outer electrons or sharing covalent bonds
• describe the structure of a metal?

  Giant lattice of positive metal ions, cat island, surrounded by a sea of delocalised electrons,
• explain my metals have high melting points?

  There is a strong electrostatic attraction between positive metal ions and delocalised electrons, which require lots of energy to overcome
• explain my metals, conduct, electricity?

  Sea of delocalised electrons, which are free to move
• define the term electrolysis?

  Decomposing an electrolyte, using a direct current
• describe what an electrolyte is?

  An ionic compound that is molten or dissolved
• explain why an electrolyte must be molten or dissolved in water to work?

  When molten or dissolved ions are free to move
• explain how ions are discharged at the cathode electrode?

  Positive ions are attracted to the cathode where they gain electrons/are reduced to form either solid metal or hydrogen gas
• Explain how answer discharge at the anode electrode?

  Negative ions are attracted to the anode when they lose electrons to form a gas
• protect the products of electrolysis of molten compounds?

  Copper ions will be attracted to the cathode where it is reduced undischarged chloride ions will be attracted to the anode by the air, oxidise and discharged
• give examples of balanced, half equation for the electrolysis of molten compounds at the anode and cathode ?

  Anode: 2Cl^-(l) -> Cl2(g) + 2e^- Cathode: 2Na^+(l) + 2e^- -> 2Na(l)
• project the products of electrolysis of aqueous, compounds, e.g. copper sulphate, sodium, chloride, zinc hydroxide?

  Cathode-will produce the matter with metals less reactive than hydrogen

  If metals, more reactive than hydrogen, hydrogen is produced

  Anode-if a halogen is present, the halogen is produced

  Otherwise oxygen is produced
• give examples of balanced, half equation for the electrolysis of aqueous compounds, e.g. copper sulphate, sodium, chloride, copper hydroxide ?

  For copper sulfate

  Cu2+ + 2e --> Cu

  for sodium chloride

  2H+ + 2e --> H2
• explain the mass changes at the anode and cathode during electrolysis using copper electrodes?

  Anode

  Mass decreases

  As copper atoms lose electrons to form ions which move into solution

  Cathode

  Mass increases

  As copper ions in solution are attracted

  They gain electrons to form atoms
• Tf Value?


  distance moved by substance

  /distance moved by the solvent
• number of particles ?

  moles X avogadros constant (6.02 X 10^23)
• number of moles?


  mass of substance

  /Ar or Mr
• Concentration?


  mass of solute

  /volume of solution
• concentration (moles)?


  number of moles of solute

  /volume of solution
• molar volume of gasses ?


  volume=number of moles X 24
• relative formula mass = number of atoms of each element x relative atomic mass
• Relative formula mass = molecular mass / 1000
• Molecular mass = sum of atomic masses
• rate of reaction?


  amount of product produced

  /time taken