chapter 3 notes part i quantitative/qualitative accuracy/precision standard units & metric...

Chapter 3 Notes Part I

Quantitative/qualitative

Accuracy/precision

Standard Units &

Metric Conversions

Types of Measurements

• Qualitative-measurements describing the qualities or characteristics of something

• Quantitative-measurements that focus on actual numerical data

What type of data is the following:

• The beaker is hot.• The beaker is 37oC.• A yellow precipitate forms.• Water has a density of

1.0g/ml.

Accuracy vs. Precision

• Accuracy-how close a measurement is to the actual value.

• Precision-how close a set of measurements are to each other.

What is an example of:

-something both accurate and precise.

-something precise but not accurate.

-something accurate but not precise.

What is the Metric System?

• Based on factors of ten

• Also Called International System (SI)

Why use metrics in science?

• Factors of ten are much easier to work with.

• Research does not just occur in the U.S.—a global community requires a universal measuring system.

Standard Units• Length

• Mass

• Time

• Temperature

• Amount of substance

Standard Units• Length - meter

• Mass - kilogram

• Time - second

• Temperature - °C

• Amount of substance - mole

Derived Units• Area

• Volume

• Density

• Concentration

• Energy

Derived Units• Area – square meter

• Volume – cubic meter

• Density – kg/m3

• Concentration – moles/Liter

• Energy - Joules

Metric Prefixes• Each prefix signifies an

amount of base units represented.

• Remember: King Henry…

• Kilo- 1000

• Hecto- 100

• Deka- 10

• Base unit

• Deci- .1 or 1/10th

• Centi- .01 or 1/100th

• Milli- .001 or 1/1000th

Other prefixes

• Mega- 1 000 000

• Giga- 1 000 000 000

• Tera- 1 000 000 000 000

• Micro- .00001 or 1/1000000th

• Nano- .000000001 or 1/billon

• Pico- .000000000001