The nature of matter

• Three different states of matter are known as solid, liquid, and gas.
• Changing temperature and/or pressure will change the state of matter of a substance.
• Solid to gas is called sublimation.
• Gas to liquid is called condensation.
• Solids:

  Have fixed volume

  High density

  Has definite shape

  Does not flow
• Liquids:

  Has fixed volume

  Moderate to high density

  No definite shape (Takes shape of container)

  Generally flows easily
• Gases:

  No fixed volume (Expands to fill container)

  Low density

  No definite shape (Takes shape of container)

  Flows easily
• Evaporation takes place from the surface of a liquid.
• The warmer the liquid the faster it evaporates.
• At a certain temperature, the entire liquid will form a gas, not just the surface.
• Volatility: how easily something evaporates
• A pure substances consists of only one substance.
• A mixture must be made from at least 2 parts, solid, liquid, gas.
• A solid that dissolves in a liquid is a solute.
• A liquid that dissolves a solid is a solvent.
• Suspension: When a solid and liquid are mixed, but the solid particles don't dissolve.
• Solution: A solute dissolved in a solvent.
• Miscible: When a solute is completely dissolved in a solvent and there is only one layer.
• Alloys: A mixture of two metals (made by mixing two liquid metals together before solidifying)
• Filtration: Separation of solids from liquids.
• The insoluble material collected on filter paper is called residue.
• The liquid collected in filtration is called the filtrate.
• Mixture of two immiscible liquids can be separated if the mixture is placed in a separating funnel. The liquids separate into different layers. The lower, denser layer is removed at the bottom.
• Separating a solid from a solution can be carried out by evaporation and crystallization.
• Evaporation gives only a powder, but crystallization can result in proper crystals.
• Both evaporation and crystallization start with the evaporation of the liquid, however evaporation is stopped when the solution has been concentrated enough. Then the solution cools down slowly and crystallizes.
• Separating a liquid from a solution is carried out through distillation.
• The boiling point of a liquid is usually much lower than the boiling point of a solid.
• Liquids are more soluble and be easily be evaporated off in a distillation flask. After it is evaporated, it is condensed by passing through a condenser and is then collected as the distillate.
• Separating a mixture from two (or more) miscible liquids uses fractional distillation, as liquids have very similar boiling points.
• In fractional distillation, the most volatile liquid in the mixture distils first.
• In fractional distillation, the mixture of liquids are heated and a thermometer is monitored. The particles of the mixture begin to evaporate at the temp increased and they rise into the fractionating column. The liquid with the lowest boiling point is first to evaporate and is collected.
• Separating two or more dissolved liquids can be carried out using chromatography.
• A drop of concentrated solution is placed on a pencil line on the chromatography paper and the paper is dipped in a solvent.
• In chromatography, the substances separate based on their solubility in the solvent. As the solvent moves up the paper, the substances are carried with it and begin to separate.
• The chromatography run is stopped before the solvent front reaches the top of the paper.
• If you keep adding a solid to a solution to the point where no more of it will dissolve at that temperature, it is a saturated solution.
• To get more solid to dissolve in a saturated solution, the temperature must be increased.
• When a saturated solution is cooled, it can hold less solute at the lower temperature and therefore some solute crystallizes out.
• Unlike most solids, gases become less soluble in water as the temperature rises.