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