Introduction to Measurements and Calculations in Chemistry J. Flint Baumwirt C-5 Chemistry

Some tourists in the Chicago Museum of National History are marveling at the dinosaur bones. One of them asks the guard. “Can you tell me how old the dinosaur bones are?” The guard replies, “They are 3 million, four years, and six months old.” “That’s an awfully exact number,” says the tourist. “How do you know their age so precisely?” The guard answers, “Well, the dinosaur bones were three million years old when I started working here, and that was four and a half year ago.”

Accuracy and Precision "Precise to 4 decimal places maybe. But doggone it, that's not an accurate measure of my weight!"

Example

Metric System The Metric System is in everyday use EVERYWHERE in the (world) except in the United States, where the old English system is used. Even the British don't use the English system! Canada and Mexico have gone metric. France first adopted the metric system in 1795! With increasing globalization, American citizens will have to learn to use metric units in everyday life as well as in their careers. It is already standard in most scientific fields.

Basic SI Units Physical Quantity Measurement Unit Symbol Lengthmeters m Masskilogramskg Timeseconds Electric CurrentampereA TemperaturekelvinK Amount of substancemolemol Luminous intensitycandelacd

Basic SI Units Physical Quantity Measurement Unit Symbol Lengthmeters m Masskilogramskg Timeseconds Electric CurrentampereA TemperaturekelvinK Amount of substancemolemol Luminous intensitycandelacd

Metric System Prefixes teraTtrillion gigaGbillion megaMmillion kilokthousand hectohhundred dekadaten BASE UNIT decidtenth centichundredth millimthousandth micro  millionth nanonbillionth picoptrillionth femtof

Metric System Prefixes teraTtrillion gigaGbillion megaMmillion kilokthousand hectohhundred dekadaten BASE UNIT decidtenth centichundredth millimthousandth micro  millionth nanonbillionth picoptrillionth femtof