Measurement & Unit Conversions Reading Ch (pp ) Why would chemistry students be interested in unit conversions? Measurements- involve a number & a unit Different measurement systems -English- (lb.,mile, inch, cup, gallon, etc.) -Metric- (gram, meter, liter, etc.)

Unit conversions, con’t Use a T-chart to solve unit conversions- this is a simple method to use equalities to cancel out unwanted units. Equalities represent 2 numerical values and their units that are equal to each other and therefore be converted. 1 mile = 5280 ft.

T-Chart Conversion Problems 1. How many inches in 2.1 miles? 2.How many liters in 68 gallons? (HINT: 1 liter = quarts) 3.How many seconds in 4.5 score of years?(1 score = 20 years) 4.How many grams in 0.95 pounds of hamburger?(454 g=1 lb.) 5. If there are 8 fluid ounces in a cup, how many fluid ounces in 4.9 gallon?

Metric System (aka- SI System) **Units are made of prefix + base unit Base units Length- meter Mass- gram Volume-liter Time- seconds Amount of substance-mole

Prefixes- are added to base units to change the value Less than 1 Deci Centi Milli Micro Nano Greater than 1 Deka Hecto Kilo Mega Giga- 10 9

Examples- Kilogram = 1000 grams or 10 3 grams Millisecond =.001 second or second What would the unit be for 100 liters? Answer: Hectoliter or 10 2 liters What would the unit be for 0.01 meter? Answer: Centimeter or meter

Conversions w/ Metric units? 1.Use t-charts. 2.Use equalities 3.Solve for wanted unit.

Metric Conversions Ex. Convert 40 kilograms to grams. 40 kg 1000 grams 1 kg = 40,000 grams

Practice with Metric Conversions 1.Convert 6.5 kg to mg 2.Convert 870 dam to cm. 3.Convert 7.80 hL to mL.

Metric Equivalents ** the base units (in bold) are interchangeable 1,000,000,000 nanometers = 1 meter 1,000,000 micrometers = 1 meter 1000 millimeters = 1 meter 100 centimeters = 1 meter 10 decimeters = 1 meter

Metric Equivalents con’t 10 meters = 1 dekameter 100 meters = 1 hectometer 1000 meters = 1 kilometer 1,000,000 meters = 1 megameter 1,000,000,000 meters = 1 gigameter