Chemistry Measurements and Units

Introduction to Measurements

• Chemistry relies on precise measurements of various physical quantities
• These quantities include length, volume, mass, time, density, and temperature
• Accurate and consistent measurements are crucial for scientific experiments and calculations

Units of Measurement

• The SI (International System of Units) is the standard system used
• The base unit of length is the meter (m)
• Other units, like centimeters (cm), millimeters (mm), and micrometers (µm) and nanometers (nm) are also in use, and their conversions to meters
• A yard is a little longer than a meter (1m = 1.094 yd)
• A centimeter is about two-fifths of an inch (1 cm = 0.3937 in)
• An inch is about 2.54 centimeters (1 in = 2.54 cm)
• The angstrom (A), micrometer (µm), nanometer (nm), and picometers (pm) are used as smaller units

Volume

• Volume is the amount of space occupied by a substance
• The Sl unit of volume is the cubic meter (m³)
• In chemistry, liters (L) and milliliters (mL) are also used
• Liter (L) = 1 cubic decimeter (dm³) = 10-3 m³
• 1 milliliter (mL) = 1 cubic centimeter (cm³) = 10-3 dm³ = 10–6 m³
• A relationship exists between length and volume, volume can be calculated by multiplying the length, width and height
• Measurement of volume using glassware like Erlenmeyer flasks, beakers, graduated cylinders, pipets, and burets for different laboratory purposes

Laboratory Techniques

• Erlenmeyer flasks are used to hold liquids
• Beakers are used to hold liquids and make mixtures
• Graduated cylinders are used to measure volumes precisely
• Pipettes and burets are used for transferring precise amounts of liquids
• Volumetric flasks are used to prepare solutions of exact concentrations