Paper 1

• Diamond is made up of only carbon atoms which form four covalent bonds each
• Graphite is made up of only carbon atoms and each carbon atoms forms 3 covalent bonds.
• The melting point of diamond is very high (4,027°) because the strong covalent bonds between the carbon atoms are difficult to break, whereas graphite has weak intermolecular forces so it can be easily broken down into layers.
• A compound is formed when two or more elements chemically combine together in fixed proportions by mass.
• Giant covalent structures do not conduct electricity.
• Only 3 out of four carbon's four outer electrons are used in bonds, so each carbon atom has one electron that's delocalised and can move. So graphite can therefore conduct electricity.
• In covalent bonding, there's a strong electrostatic attraction between the negatively charged shared electrons and the positively charged nuclei of the atoms involved.
• Ionic compounds have high melting and boiling points because they are held together by strong forces of attraction between positive and negative ions.
• To investigate solubility use ammonium chloride.
• To investigate diffusion in a liquid use potassium manganate.
• To investigate diffusion in a gas:

  1.) Soak two pieces of cotton wool in ammonia and hydrochloric acid. The ring will form closer to the hydrochloric acid, as the hydrogen chloride particles are bigger and slower than the ammonia ones.

  2.) Use bromine gas and air.
• Most metals are malleable. The layers of ions in a metal can slide over each other, making metals malleable - this means that they can be hammered or rolled into flat sheets.
• Solid ionic compounds don't conduct electricity because the ions are not free to move around. But when an ionic compound is dissolved the ions separate and are able to move in solution and are able to conduct electricity.
• State four properties of ionic compounds:

  • They have high melting and boiling points, as they require a lot of energy to break the bonds.
  • They are hard, brittle, and form crystals.
  • They dissociate into ions when dissolved in water or melted, and conduct electricity in these states.
  • They do not conduct electricity in the solid state.
• In covalent bonding, there's a strong electrostatic attraction between the negatively charged shared electrons and the positively charged nuclei of the atoms involved.
• 1 mole = 6.02 x 10^23
• One mole of atoms or molecules of any substance will have a mass in grams equal to the relative particle mass (Ar or Mr) for that substance.
• Carbon has an Ar of 12 so one mole of carbon weighs exactly 12g.
• Carbon dioxide has an Mr of 44 so one mole of it will weigh exactly 44g.
• The molar mass of a substance is just another way of saying the mass of one mole of that substance.
• Moles= Mass/Mr
• To find an Empirical formula use combustion with magnesium oxide.
• A solid salt containing water of crystallisation is hydrated.
• If a salt doesn't contain any water of crystallisation, it's called anhydrous.
• General formula- An algebraic formula that can describe any member of a family of compounds.
• Displayed formula- Shows how all the atoms are arranged, and all the bonds between them.
• Structural formula- Shows the arrangement of atoms carbon by carbon, with the attached hydrogens and functional groups.
• Two molecules are isomers of one another is they have the same molecular formula but the atoms are arranged differently.
• A homologous series is a group of compounds that can all be represented by the same general formula.
• Compounds in a homologous series have the similar chemical properties and react similarly but different physical properties.
• A functional group is a group of atoms that determine how a compound typically reacts.
• Number of carbons 1- meth 2- eth 3- prop 4- but 5- pent 6- hex 7- hept 8- oct 9- non
• Meth - eth - prop - but - pent - hex
• Alkanes have single bonds
• Alkenes have at least one double bond
• Heat energy transferred (J) = Mass of liquid being heated (g) X Specific Heat capacity (J/g/°C) X change in temperature of the liquid (°C)
• Lithium, Li+, burns with a red flame.
• Sodium, Na+, burns with a yellow flame.
• Potassium, K+, burns with a lilac flame.
• Calcium, Ca2+, burns with an orange-red flame.