Experimental Chemistry

• During the 1960 Olympic Games, two competitive swimmers seemed to have finished at about the same time. Timekeepers determined that Lance Larson was faster. However, the finish judges decided that John Devitt touched home first, based on what they had observed. This controversy led to electronic touch pads being installed on the walls of pools (Figure 1.1) to determine the exact timing each swimmer takes.
• Time


  A physical quantity that is important to measure and quantify so that we can study and learn about the data
• Common physical quantities used in experiments

  • time
  • temperature
  • length
  • mass
  • volume
• International System of Units (SI units)


  A common standard for recording measurements
• Physical Quantity


  • time
  • temperature
  • length
  • mass
  • volume
• time


  how long it takes for something to happen
• temperature


  how hot or cold something is
• length


  the distance between two points
• mass


  how much matter is present in a substance
• volume


  the amount of space something occupies
• Touch pads in swimming pools are used to decide the winners in competitive swimming.
• Second


  The SI unit for time
• Chemical reactions can take place far more quickly than the second, but experiments can also take a much longer period of time to complete
• Units for measuring time

  • Second
  • Minute
  • Hour
• 1 minute


  60 seconds
• 1 hour


  • 60 minutes
  • 3600 seconds
• Digital stopwatch


  • Used in the laboratory to measure time
• Mechanical or analogue stopwatch


  • Can also be used to measure time
• Table 1.2 shows the smallest division of digital and analogue stopwatches
• Digital stopwatch


  • 0.01 second
• Analogue stopwatch


  • 0.1 second
• Kelvin


  The SI unit for temperature
• Degree Celsius


  Another common unit for measuring temperature
• Temperature in Kelvin


  Temperature in Celsius + 273
• Digital thermometer


  • Used in the laboratory to measure temperature
• Alcohol thermometer


  • Analogue thermometer used in the laboratory
• Mercury thermometer


  • Analogue thermometer used in the laboratory
• Temperature sensors or probes


  • Connected to data loggers to measure and collect temperature data automatically
• Alcohol thermometers in most school laboratories show a range of about -10°C to 110°C
• Metre


  The SI unit for length
• Units for measuring shorter lengths

  • Millimetre
  • Centimetre
  • Decimetre
• 1 metre


  • 10 decimetres
  • 100 centimetres
  • 1000 millimetres
• Metre rule


  • Apparatus for measuring length with an accuracy of ±0.1 cm
• Measuring tape


  • Apparatus for measuring length with accuracies ranging from ±0.1 cm to ±0.5 cm
• In chemistry, even smaller units of length are required for measurement due to the small size of atoms and molecules
• Kilogram


  The SI unit for mass
• Units for measuring smaller masses

  • Gram
  • Milligram
• 1 kilogram


  • 1000 grams
  • 1,000,000 milligrams
• Tonne


  Unit for measuring large masses, used in chemical factories and refineries
• Kilotonne


  Unit for measuring large masses, used in chemical factories and refineries