CHEM 1405

• * quantitative observation
• * comparison to an agreed upon standard
• * every measurement has a number and a unit

• * also called exponential notation
• * used to write large numbers in small format

• a.bcd x 10^e
• a.bcd = coefficient
• e = exponent

• * positive exponent means 1 multiplied by 10 e times
• * negative exponent means 1 divided by 10 e times

• Quantity Unit Symbol
• length meter m
• mass kilogram kg
• time second t
• temperature kelvin k

kilo: larger than the base unit 1km = 1000m = 10³m

centi: 100x smaller than base unit 1cm = 0.01m = 10^-2m

milli: 1000x smaller than base unit 1mm = 0.001m = 10^-3m

• Mass gram g
• Length meter m
• Time seconds s