1.4 – UNITS OF MEASUREMENT

SUMMER AP CHEMISTRY HOMEWORK

CHAPTER 1

SI UNITS

These 5 will

appear in this

course!

THE METRIC SYSTEM

• Scientists use the metric system for all experimental measurements

• Based on the power of 10 (each prefix is a power of 10 away from the previous prefix)

• Information on how to convert between prefixes can be found in section 1.6 of this unit.

Most Important

TEMPERATURE

• There are two scales used in chemistry is the Kelvin and Celsius temperature scale

• Kelvin is the official SI system based on the concept of absolute zero. We convert between Celsius and Kelvin using:

K = oC + 273.15

• The other scale is Celsius. To convert between Celsius and Fahrenheit scale we use the equation:

DERIVED UNITS: VOLUME

• The SI units are used to create all other units. These units are known as derived units.

• Volume is a derived unit

• Volume is the cube of a substances length (i.e. the derived SI unit for volume is m3).

• Any metric unit cubed can be a unit of volume (e.g. mm3, cm3, etc.)

DERIVED UNITS: DENSITY

• Density is the mass per unit of volume:

• Remember, less dense substances float atop more dense substances.

Least dense liquid

Most dense liquid

CLASS EXAMPLE

• Calculate the density of Hg if 1.00 x 102 g occupies a volume of 7.36 cm3

CLASS EXAMPLE• What is the mass in grams of

a cube of gold (density = 19.32 g/cm3) if the length of the cube is 2.00 cm?