Chem chap1

• Four methods of collecting gases

  gas syringe, water displacement, upward delivery, downward delivery
• how many cm3 does gas syringe collect up to

  100cm3
• is solution more or less dense than air for downward delivery

  more dense
• 3 methods of drying gases

  Concentrated sulfuric acid, quicklime(calcium oxide), fused calcium chloride
• What can dry most gases except alkalis?

  Concentrated sulfuric acid
• What is the only method to dry ammonia?

  Quicklime (calcium oxide)
• What drying method must be heated before use?

  Fused calcium chloride
• What drying method is used for hydrogen, nitrogen and carbon dioxide?

  Fused calcium chloride
• Does separating funnel separate heterogeneous or homogeneous mixtures?

  heterogeneous
• What are the factors of chromatography?

  Temperature, type of solvent
• what is the formula for retention value?

  Distance travelled by substance/ distance travelled by solvent
• What do glass beads do?

  Increase surface area for vapours to condense in fractionating column
• 3 methods for better fractional distillation separation

  Longer fractionating column, smaller glass beads, more glass beads
• How to tell if a substance is pure?

  fixed boiling/melting point
• What do locating agents/ uv light do?

  Reacts with substances that are colourless in solvent, making them visible and allows us to see them