Summary Chemistry notes

MEASUREMENT
Time

 Time can be measured using a stopwatch or stopclock which are usually
accurate to one or two decimal places
 The units of time normally used are seconds or minutes although other
units may be used for extremely slow reactions (e.g. rusting)
 1 minute = 60 seconds

Temperature

 Temperature is measured with a thermometer which can normally give
readings to the nearest degree Celsius
 Digital thermometers are available which are more precise than traditional
thermometers
 Traditional thermometers rely upon the uniform expansion and contraction
of a liquid substance with temperature; they tend to be
more accurate than digital thermometers which often need to be re-
calibrated
 The units of temperature are degrees Celsius (ºC)

Mass

 Mass is measured using a digital balance which normally give readings to
two decimal places. These must be tared (set to zero) before use
 The standard unit of mass is kilograms (kg) but in chemistry grams (g) are
most often used
 1 kilogram = 1000 grams

Volume-liquids

 The volume of a liquid can be determined using several types of
apparatus, depending on the level of accuracy needed
 For approximate volumes where accuracy isn´t an important factor,
measuring cylinders are used. These are graduated (have a scale so can