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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.
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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