Chapter 1-6

Precision v.s. Accuracy

• Accuracy = how close a measurement is to the value

• Precision = how close repeated measurements are to each other

Extensive v.s. Intensive

Extensive = Measurable; value changes if cut in half; quantity

Intensive = Observable; stays the same when cut in half; quality

Base SI Units

• Length

• Mass

• Time

• Temperature

• Amount of substance

• Electric current

• Luminous intensity

• Length → meter (m)

• Mass → kilogram (kg)

• Time → second (s)

• Temperature → kelvin (K)

• Amount of substance → mole (mol)

• Electric current → ampere (A)

• Luminous intensity → candela (cd)

Exact Numbers

Ex. 1 in = 2.54 cm & Dozen eggs = 12 eggs
Sig figs don’t affect exact, but affect measured numbers

Mass of Proton, Neutron, and Electron in amu

Proton & Neutron = 1

Electron = 0 ← leads to a small error in calculations

Compound

2 or more elements in a fixed ratio

Are atoms in a mixture in a fixed ratio?

No

What are the rules for naming nonmetal-nonmetal compounds?

• Element to the left is first in the name & formula

• Multiplying prefix used to show elements with more than 1 atom (di-, tri- hexa-)

• Must use mono- prefix for 2nd element if it has one atom

• 2nd word ends in -ide