Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Chapter 1 Chemistry and Measurements 1.3 Units of Measurement 1

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Units of Measurement Scientists use the metric system of measurement and have adopted a modification of the metric system called the International System of Units as a worldwide standard. International System of Units (SI) is an official system of measurement used throughout the world for units in length, volume, mass, temperature, and time. 2

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Units of Measurement, Metric and SI 3

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Length, Meter (m) and Centimeter (cm) 4 1 m = 100 cm1 m = 1.09 yd 1 m = 39.4 in.2.54 cm = 1 in.

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Volume, Liter (L) and Milliliter (mL) 1 L = 1000 mL 1 L = 1.06 qt 946 mL = 1 qt 5 We use graduated cylinders to measure small volumes.

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Mass, Gram (g) and Kilogram (kg) 1 kg = 1000 g 1 kg = 2.20 lb 454 g = 1 lb The mass of a nickel is 5.01 g on an electronic scale. 6

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Temperature, Celsius ( o C) and Kelvin (K) Water freezes: 32 o F 0 o C The Kelvin scale for temperature begins at the lowest possible temperature, 0 K. A thermometer is used to measure temperature. 7

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Time, Second (s) The second is the correct metric and SI unit for time. The standard measure for 1 s is an atomic clock. A stopwatch is used to measure the time of a race. 8

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check What are the SI units for the following? A. volume B. mass C. length D. temperature 9

Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution What are the SI units for the following? A. The SI unit for volume is the cubic meter, m 3. B. The SI unit for mass is the kilogram, kg. C. The SI unit for length is the meter, m. D. The SI unit for temperature is Kelvin, K. 10