unit 1.1

• Si unit of temperature is Kelvin(K)
• SI unit for time is seconds (s)
• we use digital stop watches and analog stopwatches to measure time in lab
• digital stopwatches measure time to the nearest hundredth of a second (+/- 0.01s)
• analog stopwatch measures time to the nearest tenth of a second (+/- 0.1s)
• we use, in sequence of what is more common, alcohol and mercury thermometers, digital thermometer and a data logger in lab
• SI unit for length is the meter (m)
• What is the most common apparatus used to measure temperature?

  alcohol and mercury thermometer
• we use metre rule and measuring tapes in lab
• SI unit for mass is kilograms (kg)
• we use a beam balance and a digital balance to measure mass
• digital balance measures to the nearest hundredth of a gram (+/- 0.01g)
• SI unit for volume is cubic meter (m3)
• Some experiments require a fixed volume of chemicals, while others require a range of volume
• In the lab, we use the following equipment for measuring volume:

  • P -pipette
  • V -volumetric flask
  • M -measuring cylinder
  • B -burette
• Pipette:

  • Measures a fixed volume (10.0 cm3 or 25.0 cm3)
• Volumetric flask:

  • Measures a fixed volume that is larger (100 cm3 or 250 cm3)
• Measuring cylinder:

  • Measures a range of volume to the nearest tenth cubic centimeter (+/- 0.5 cm3)
  • Examples: 31.5 cm3, 23.0 cm3
• Burette:

  • Measures a range of volume, up to 50 cm3, to the nearest hundredth cubic centimeter (+/- 0.05 cm3)
  • Examples: 31.55 cm3, 23.00 cm3
• in order, pipette, volumetric flask, measuring cylinder and burette

  
• when reading measurements for liquids we should always position our eyes at the meniscus