Science loves units. But then again, they are a necessity. If you are going to measure something, you will need a way to tell people how much you have. Here are only a few we use in Chemistry...
When you need to know how much of something you have compared to a whole. It is figured out by taking a decimal number and multiplying by 100.
"I have 20% of what I started with." That means you lost 80%.
GRAMS, KILOGRAMS, MILLIGRAMS
These are measures of mass.
"This candy bar has a mass of only a few grams."
These are measures of volume.
"I just bought a 2 liter bottle of soda."
DEGREES CELSIUS, DEGREES FAHRENHEIT, AND KELVIN
These are different measurements scientists use for temperatures.
"It's freezing outside." That could mean it is 0oC, 32oF, or 273K (just Kelvins, no degrees).
ATOMIC MASS UNITS
The way to measure the mass of different atoms.
"Carbon-12 weighs 12 AMU."
A unit of energy.
"A calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius."
It is a unit of energy.
"4.8 Joules is the same as 1 Calorie."
SECONDS, MINUTES, HOURS
Measures of time.
"There are 60 seconds in a minute and 60 minutes in an hour."