Chemistry Conversions Dimensional Analysis and Atoms, Elements, Compounds

Exponential Multiplier SI Prefixes Prefix Abbreviation Exponential Multiplier Meaning Example using length Kilo- k 103 1000 1 kilometer (km) = 1000 m Hecto- h 102 100 1 hectometer (hm) = 100 m Deka- da 101 10 1 dekameter (dam) = 10 m 1 1 meter (m) Deci- d 10-1 1/10 1 decimeter (dm) = 0.1 m Centi- c 10-2 1/100 1 centimeter (cm) = 0.01 m Milli- m 10-3 1/1000 1 millimeter (mm) = 0.001 m

Converting From One Unit to Another We will convert A LOT! Uses a technique called Factor Label Method Cancels out units and does the math for you!!

Factor-Label Method for Conversions Mathematics used Numbers, rather than Quantities Chemistry uses these same Numbers along with the value’s Units A Number is useless without its unit Units give the Number an actual meaning

1 foot / 12 inches or 12 inches / 1 foot, Conversion Factors A conversion Factor is needed to go from one unit to another You must first know how much of one thing is of another before making any conversions We all know 1 foot is made up of 12 inches SO… The conversion factor needed to go from feet to inches or from inches to feet is 1 foot / 12 inches or 12 inches / 1 foot, Respectively.

Let’s try using 1 pound = 0.454 Kilograms Conversion Factors 1 mile = 1.61 Kilometers 1 inch = 2.54 centimeters 1 gallon = 3.71 Liters Let’s try using 1 pound = 0.454 Kilograms

Conversions 1 pound = 0.454 Kg 157 lb 0.454 kg 1 lb The “Heart” of the problem is where the conversion actually takes place. This is where your conversion factor does its work.

Conversions 1 pound = 0.454 Kg 157 lb 0.454 kg 1 lb ( 157 * 0.454 ) / 1 = 71 = 71 kg So yes, with the proper units 157 lb does equal 71 kg, but without units the values are not the same, as we do not know the correct representation numbers.

Units Units are everything. They give any value an actual meaning and interpretation. Always carry your units through, rewriting them until you reach a final value, or you will be lost.

English System (American System) Conversions Factors: 1 foot = 12 inches 1 yard = 3 feet 1 mile = 5,280 feet = 1,760 yards 1 gallon = 16 cups = 4 quarts = 8 pints 1 pound = 16 ounces

Converting with English Units Question: Convert 15.41 yards to inches: Conversion Factors: 1 yard = 3 feet 1 foot = 12 inches

Converting with Metric Units Convert 15.41 yards to inches: 15.41 yd Conversion Factors: 1 yard = 3 feet 1 foot = 12 inches

Converting with Metric Units Convert 15.41 yards to inches: 15.41 yd 3 ft 1 yd Conversion Factors: 1 yard = 3 feet 1 foot = 12 inches

Converting with Metric Units Convert 15.41 yards to inches: 15.41 yd 3 ft 12 in. 1 yd 1 ft Conversion Factors: 1 yard = 3 feet 1 foot = 12 inches

Converting with Metric Units Convert 15.41 yards to inches: 15.41 yd 3 ft 12 in. 1 yd 1 ft = (15.4 * 3 * 12) / 1 15.41 yards = 554.76 inches

Metric System Common Metric Prefixes: Kilometer Hectometer Dekameter Abbreviation Value (Base Unit) Kilometer km 1000 Hectometer hm 100 Dekameter dam 10 Base Unit (meter) meter 1 Centimeter cm 0.01 Millimeter mm 0.001 Micrometer µm 0.000001

Converting with Metric Units Question: Convert 0.248 km to centimeters: Conversion Factors: 1 Kilometer = 1000 meters 1 meter = 100 centimeters Prefix Abbreviation Value (Base Unit) Kilometer km 1000 Hectometer hm 100 Dekameter dam 10 Base Unit (meter) meter 1 Centimeter cm 0.01 Millimeter mm 0.001 Micrometer µm 0.000001

Converting with Metric Units Covert 0.248 km to centimeters: 0.248 km Conversion Factors: 1 Kilometer = 1000 meters 1 meter = 100 centimeters

Converting with Metric Units Covert 0.248 km to centimeters: 0.248 km 1000 m 1 km Conversion Factors: 1 Kilometer = 1000 meters 1 meter = 100 centimeters

Converting with Metric Units Convert 0.248 km to centimeters: 0.248 km 1000 m 100 cm 1 km 1m Conversion Factors: 1 Kilometer = 1000 meters 1 meter = 100 centimeters

Converting with Metric Units Convert 0.248 km to centimeters: 0.248 km 1000 m 100 cm 1 km 1m = (0.248 * 1000 * 100) / 1 = 24,800 centimeters Much Easier!

Calculations: Metric Vs. American System? Prefix Abbreviation Value (Base Unit) Kilometer km 1000 Hectometer hm 100 Dekameter dam 10 Base Unit (meter) meter 1 Centimeter cm 0.01 Millimeter mm 0.001 Micrometer µm 0.000001 Just count the zeros and move the decimal spot to the left or the right.