Experimental techniques
2.1 Measurement
Name appropriate apparatus for the measurement of time, temperature, mass and volume,
including burettes, pipettes and measuring cylinders
Time
Time can be measured using a stopwatch or stop clock 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)
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 set to zero before use.
The standard unit of mass is kilograms (kg) but in chemistry grams (g) are most often used
1kg = 1000g
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 be used to measure) and are available in 25
cm3, 50 cm3, 100 cm3, and 250 cm3.
Pipettes are the most accurate way of measuring a fixed volume of liquid, usually 10 cm 3, or
25 cm3
Classroom pipettes require you to watch the liquid rising up the pipette
Laboratory pipettes will only pull a specified volume into the tip of the pipette
Burettes are the most accurate way of measuring a variable volume of liquid between 0 cm 3
and 50 cm3 (e.g. in a titration)
Gases
The volume of a gas sometimes needs to be measured and is done by collecting it in a
graduated measuring apparatus
A gas syringe is usually the apparatus used
A graduated cylinder inverted in water may also be used, provided the gas isn’t water-
soluble
If the gas happens to be heavier than air and is coloured, the cylinder can be used upright
2.1 Measurement
Name appropriate apparatus for the measurement of time, temperature, mass and volume,
including burettes, pipettes and measuring cylinders
Time
Time can be measured using a stopwatch or stop clock 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)
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 set to zero before use.
The standard unit of mass is kilograms (kg) but in chemistry grams (g) are most often used
1kg = 1000g
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 be used to measure) and are available in 25
cm3, 50 cm3, 100 cm3, and 250 cm3.
Pipettes are the most accurate way of measuring a fixed volume of liquid, usually 10 cm 3, or
25 cm3
Classroom pipettes require you to watch the liquid rising up the pipette
Laboratory pipettes will only pull a specified volume into the tip of the pipette
Burettes are the most accurate way of measuring a variable volume of liquid between 0 cm 3
and 50 cm3 (e.g. in a titration)
Gases
The volume of a gas sometimes needs to be measured and is done by collecting it in a
graduated measuring apparatus
A gas syringe is usually the apparatus used
A graduated cylinder inverted in water may also be used, provided the gas isn’t water-
soluble
If the gas happens to be heavier than air and is coloured, the cylinder can be used upright
