Summary maps

• What is the purpose of a pipette?

  To measure and transfer a specific volume of liquid
• What is the purpose of a burette?

  To deliver variable volumes of liquid accurately
• What is the method of collection for gas using a graduated gas syringe?


  • To collect and measure the volume of gas produced
  • Example: Gas produced during a reaction between an acid and a metal/metal carbonate
• What is the SI unit for time?


  Seconds (s)
• What is the SI unit for temperature?

  Kelvin (K)
• What is the SI unit for mass?


  Kilograms (kg)
• What is the SI unit for length?


  Metre (m)
• What is the SI unit for volume of gas?


  Cubic metre (m³)
• What is the SI unit for volume of liquids?


  Cubic metre (m³)
• What are the accuracy levels of different measuring apparatus?


  • Beaker, conical flask: Estimate, Rough
  • Measuring cylinder: 0.5 cm³
  • Pipette: 0.1 cm³
  • Burette: 0.05 cm³
• What is the method of collection for gases that are soluble in water and less dense than air?

  Upward delivery
• What is the method of collection for gases that are soluble in water and denser than air?

  Downward delivery
• What is the method of collection for gases that are insoluble or slightly soluble in water?

  Displacement of water
• What are examples of gases and their solubility in water?


  • Ammonia (NH₃): Soluble
  • Sulfur dioxide (SO₂): Soluble
  • Chlorine (Cl₂): Soluble
  • Hydrogen chloride (HCl): Soluble
  • Carbon dioxide (CO₂): Soluble
  • Hydrogen (H₂): Insoluble
  • Oxygen (O₂): Insoluble
• What are the tests for purity of a substance?

  1. Fixed melting point and boiling point
  2. Only one spot on the chromatogram
• What are the effects of impurities on melting and boiling points?


  1. Lower melting point
  2. Higher boiling point
  3. Melts and boils over a range of temperatures
• What are some separation techniques for mixtures?

  • Magnetic Attraction
  • Sieving
  • Using Suitable Solvents
  • Filtration
  • Evaporation to Dryness
  • Crystallisation
  • Simple Distillation
  • Fractional Distillation
  • Paper Chromatography
• What is a mixture?


  Two or more substances that are not chemically combined together
• What is the purpose of filtration in separating solid-liquid mixtures?


  • To obtain either the solid or liquid
  • Residue: insoluble solid collected on filter paper
  • Filtrate: solution collected in conical flask
• What is the purpose of evaporation to dryness?


  To obtain the soluble solid
• What is the process of crystallisation?


  • Heating mixture to get a saturated solution
  • Allowing hot saturated solution to cool to form crystals
  • Filter to collect crystals
  • Wash crystals with cold distilled water and dry between pieces of filter paper
• What is simple distillation used for?


  • To obtain the liquid
  • Involves boiling and condensation
  • Collects pure liquid as distillate
• What is fractional distillation used for?


  • To obtain liquids from miscible mixtures
  • Uses a fractionating column for efficient separation
• What is paper chromatography used for?


  • To separate components based on different solubilities
  • Starting line drawn with pencil to avoid interference
• What are the properties of solids, liquids, and gases in terms of forces of attraction?


  • Solid: very strong forces of attraction
  • Liquid: strong forces of attraction
  • Gas: very weak forces of attraction
• What happens to particles during melting and boiling?


  • Melting: particles gain thermal energy and vibrate faster
  • Boiling: particles gain thermal energy and move quickly in all directions
• What happens to particles during freezing and condensation?


  • Freezing: particles lose kinetic energy and become orderly
  • Condensation: particles lose kinetic energy and move closer together
• What is the maximum number of electrons in the first shell of an atom?


  2
• What is the maximum number of electrons in the second and third shells of an atom?


  8
• What are valence electrons?


  • Electrons in the outermost shell
  • Determine the chemical properties of the element
  • Atoms with the same number of valence electrons are in the same group in the Periodic Table
• How many valence electrons does a sodium atom have?


  1
• What is the electronic structure of a sodium atom?


  • 1st shell: maximum of 2 electrons
  • 2nd and 3rd shell: maximum of 8 electrons
• What is the relative mass of a proton?


  1
• What is the relative charge of an electron?


  • 1
• Where are neutrons found in an atom?


  In the nucleus
• What is the relative mass of a neutron?


  1
• What is the relative charge of a proton?


  +1
• What is the relative mass of an electron?


  1/1840
• What is the charge of a neutron?


  0
• What is the charge of a proton?


  +1