T2W1L4: Properties of Matter

we need to consider solubility of substances
heterogeneous mixture
- consists of two or more phases e.g oil and water, sand and water
homogenous mixture
- solution (heterogeneous mixture is NOT a solution)
decanting
filtration
- depends on size of particles
- funnel will utilise gravity to filter out the mixture.
- residue: material left on the filter paper (in our case sand)
  - the residue left will most likely not be pure
  - there will be water on the sand
    - distilled water will take out sodium chloride in the residue.
evaporation
- using evaporating basin (made of porcelain and has a particular shape), to evaporate the

solubility

solute: substance that is dissolved
residue: substance that is left that cannot be dissolved
precipitate: substances that are formed in a reaction when two solutions form together.
solvent is the thing solute is dissolved with.
solution is the homogeneous mixture of solute dissolved in solvent.
- process of forming solutions involves breaking the bonds and attractions
- this requires energy which is an endothermic process

ion-dipole attraction
- attraction between an ion and a dipole dipole attracted molecule.
attractions forming between the solvent and solute
- so the bond is an exothermic process
whether the solution forms depends on if the process requires too much energy to be favourable.
dissolving can be endothermic or exothermic

polarity of solvent matters.
highly polar solvent dissolves only substances that has some sort of charge.
if its an ionic compound dissolved in water, ion-dipole attraction will occur.
water is more polar than ethanol
- ethanol cannot dissolve sodium chloride, as forces of attraction that is formed between ions and ethanol molecules is not strong enough to overcome ionic bonds between ions in sodium chloride.
non-polar solvents
- cyclohexane $C_{6} H_{12}$
- benzene $C_{6} H_{6}$
- these non-polar solvents can only dissolve non-polar substances
water is the universal solvent
- water is great at dissolving polar molecules substances and many ionic substances.
- water can form a great range of intermolecular forces to stabilise solution:
  - dipole
  - hydrogen bonds
  - ion-dipole bonds