It may be the simplest topic on the first test in General Chemistry, but the idea of units appears several times as you progress through your studies of Chemistry and Physics.
A number by itself doesn’t tell you the measurement. When all the units are listed, it is possible to do math to change something with units you don’t want to something with the units you need.
- 12 inches = 1 foot
- 3 feet = 1 yard
- 2.54 cm = 1 inch
- 100 cm = 1 m
- 1000 m = 1 km
- 5280 feet = 1 mile
Here is one you want to memorize as you begin your studies as a chemist:
Write it on a small piece of paper, carry it around, and pull it out and read it when no one is looking.
Appendix A: Cancellation Error = Incorrect Math
Students may make a comment like, ” I know I got that problem wrong on the test, because the units for my answer were wrong.” Example: Getting a unit of distance for a problem that was supposed to calculate velocity.
Rob Sterling 