measuring

• Measuring liquids

  • Volumetric pipette
  • Burette
  • Measuring cylinder
• Volumetric pipette

  • Accurate volume of liquid
  • Pipette filler - safely control amount liquid drawing up
  • Calibrated - allow for fact last drop liquid
• Burette

  • Tap - drop by drop
  • How much liquid used = difference initial reading AND final reading
• Measuring cylinder

  • Suitable size - prevent error (gradation too big)
  • Less accurate than pipette/burette
• Measuring solid

  1. Put container - set balance to zero

  2. TO transfer all solid from reaction vessel to container

  3. If dissolve solid in solvent (make solution): wash remaining solid into new container using solvent

  4. Weigh mass empty container -> reweigh container with solid transferred -> difference in mass = amount of solid added
• Measuring gas

  • Gas syringe
  • Displace water from measuring cylinder
• Measuring gas by displacing water from measuring cylinder

  1. Record initial lvl of water in measuring cylinder

  2. As gas produced enter delivery tube - water pushed out

  3. Difference initial lvl AND recorded final lvl = volume gas
• Measuring gas requirement - equipment sealed - gas escape, results inaccurate
• Measure temperature accurately (thermometer)

  1. Bulb is completely submerged. NOT TOUCHING inside of container

  2. When take initial reading: wait tmp stabilise

  3. Read scale at eye level - prevent parallax error
• Measure time taken (stopwatch)

  1. Sensitive to nearest 0.01s

  2. Start and stop exactly right time
• Collect gas in test tube

  1. Gas displace air

  2. Upward delivery - lighter than air gas (Hydrogen)

  3. Downward - heavier than air (carbon dioxide, chlorine)