I). Measurements:
The study of chemistry requires the measurement of various quantities, such as mass and volume.
Mass:
The mass of a substance is the amount of matter it contains. Its unit is the gram (g) for small amounts or the kilogram (kg) for larger amounts. It is measured using a beam balance or an electronic balance.
Fig 1.1. Beam Balance
Fig 1.2. Electronic balance.
Time:
The S.I unit for time is seconds (s). Other units are minutes (min) and hours (h). A stopwatch or a stopclock is used to measure time.
Fig 1.3 A digital stopwatch
Temperature:
The S.I unit for temp is Kelvin (K). Another unit is the degree Celsius (°C).
Temperature can be measured using a thermometer. The mercury-in-glass and the alcohol-in-glass thermometers are commonly used in labs, with ranges from -10 to 110°C.
Volume:
The volume of a substance is the amount of space it occupies. It is measured in cubic centimeters (cm³), cubic decimeters (dm³) or liters (l). There are many lab apparatuses used for measuring the volume of a fluid.
Some of these are as follows:
Fig 1.4. A beaker is used to measure approximate volumes.
Fig 1.5. A measuring cylinder is accurate to the nearest cm³.
Fig 1.6. A burette is accurate to the nearest 0.1 cm³. The volume of liquid required is run off from the bottom through a tap.
Fig 1.7. A pipette measures fixed volumes (25cm³, 50cm³, 10cm³, etc.) very accurately.