CW 2.1 Name_________________ Conversion Factors Made Easy Answer the following mathematical equations 38.5 38.5 38.5 38.5 x x x x 1 = ______ 1 x 1 = _______ 1 x 1 x 1 = ______ 1 x 1 x 1 x 1 = ______ Solve these problems The same thing = ________ The same thing If a = b, then a = ______, and b = _______ b a One dozen = 12, so 1 m = 10 dm, so 60 sec =1 min, so 1 dozen = _____, 12 1m = ______, 10 dm 60 sec = _____, 1 min and 12 = _______ 1 dozen and 10 dm = _______ 1m and 1 min = ______ 60 sec We call numbers like Another example is 55 mph, or 55 miles per hour, or 55 miles . This is a fixed Hour definition conversion factor. Word problems often include these in their “knowns” or “givens.” When working problems be sure to look for these. Read this word problem and try to fill in the conversion factor list below it 60 sec_ a conversion factor. All conversion factors 1 min equal one. We might refer to it as 60 seconds per minute. Mrs. Heck has 7 guests at her house. She is going to make each guest an omelet. Each omelet takes three eggs. If Mrs. Heck makes an omelet for each guest, how many cartons of eggs will it take, if a carton holds twelve eggs? I omelet ___ guest 3 eggs __ ______ __ ______ 12 eggs Dimensional Analysis Made Easy 2 Common Conversion Factors Long Measure - Length Capacity - Liquid Measure 12 inches 3 feet 5 1/2 yards 40 rods 22 yards 10 chains 8 furlongs 5280 feet 1760 yards 3 miles 4 gills = 16 fluid oz = 2 pints = 4 quarts = 31 1/2 gallons= 2 barrels = = = = = = = = = = = 1 1 1 1 1 1 1 1 1 1 foot yard rod furlong chain furlong mile mile mile league = = = = = = = 1 1 1 1 1 1 1 square square square rood acre acre square pint pint quart gallon barrel hogshead Capacity -Dry Measure 2 pints 8 quarts 4 pecks 36 bushels Square Measure - Area 144 sq.inches 9 sq. feet 30 1/4 sq.yards 40 sq. rods 4 roods 4840 sq. yards 640 acres 1 1 1 1 1 1 foot yard rod mile = = = = 1 1 1 1 quart peck bushel chaldron Mariner's Measure 6 feet = 1 fathom 120 fathoms = 1 cable length 7 1/3 cable lengths = 1 mile 5,280 ft = 1 statute mile 6,080.2 feet = 1 nautical mile Volume - Cubic Measure 1728 cu. ins = 27 cu. feet = 128 cu. feet = 40 cu. feet = 2150.42 cu ins= 231 cu inches = 1 cu foot = 1 cubic foot 1 cubic yard 1 cord wood 1 ton (shipping) 1 standard bush. 1 std US gallon about 4/5 bushel Time Measure 60 seconds 60 minutes 24 hours 7 days 28.29.30 or 31 days 365 days 366 days = = = = 1 1 1 1 minute hour day week = 1 cal month = 1 year = 1 leap year Using the above conversion chart, write out five different conversion factors, and then flip them. This is called their reciprocal. Remember, if you flip a conversion factor over it is still “one.” Ex: 12 months = 1 year _1 year__ 12 months Dimensional Analysis Made Easy 3 A Recipe for Solving Problems Using Dimensional Analysis Ingredients: 1 chemistry word problem 1 DA track 2-3 good conversion factors Word Problem: Mrs. Heck has 7 guests at her house. She is going to make each guest an omelet. Each omelet takes three eggs. If Mrs. Heck makes an omelet for each guest, how many cartons of eggs will it take, if a carton holds twelve eggs? Directions: 1. Draw a Dimensional Analysis (DA) track. a. Draw a straight line with an equal sign at the end. = b. Place a “?” followed by the units requested for the answer to the word problem, to the right of the “=” sign. = ? cartons c. Place the “known” quantity that determines the outcome to the word problem on the left-top of the DA track, and draw a vertical line. 7 guests = ? cartons d. Insert conversion factors that will make all the units cancel except the unit you’re looking for. Draw vertical lines to separate factors. 7 guests 1 omelet 1 guest 3 eggs 1 omelet 1 carton 12 eggs = ? cartons e. Draw through the units that cancel (ex: guest cancels guest, eggs cancel eggs). Multiply the numbers left in the numerator and the denominator, and divide the numerator by the denominator to get the final answer. 7 guests 1 omelet 1 guest 3 eggs 1 omelet 1 carton 12 eggs = ? cartons (7 x 1 x 3 x 1)/(1 x 1 x 12) = 1.75 cartons Answer Dimensional Analysis Made Easy 4 Work the following problems using the DA track recipe EX: How many seconds in 35 minutes? = ? seconds 35 mins 35 mins = ? seconds 60 sec 1 min = ? seconds (35 x 60 sec)/1 = 2100 sec You will only draw one DA track when you work your problems. The example above has three DA tracks only to help illustrate the process. Problems 1. How many hours are in six days? 2. How many miles in 2640 yards? 3. What is the cost of three shirts, if a box containing 12 shirts cost $27.00? 4. How far will a car travel in 10 seconds if it is going 60 mph? 5. If solution A weighs 22 grams, and its density is 6 grams/liter, how many liters of solution A do you have?