LecturePLUS Timberlake1 Chapter 1 Measurements Using Conversion Factors

LecturePLUS Timberlake2 Initial and Final Units 1. A person has a height of 2.0 meters. What is that height in inches? Initial unit = mFinal unit = _______ 2) Blood has a density of 0.05 g/mL. If a person lost 0.30 pints of blood at 18°C, how many ounces of blood would that be? Initial = pintsFinal unit = _______

LecturePLUS Timberlake3 How many minutes are in 2.5 hours ? Initial unit 2.5 hr Conversion Final factor unit 2.5 hr x 60 min = 150 min 1 hr cancel Answer (2 SF)

LecturePLUS Timberlake4 Learning Check CF1 A rattlesnake is 2.44 m long. How long is the snake in cm? 1) 2440 cm 2)244 cm 3)24.4 cm

LecturePLUS Timberlake5 Solution CF1 A rattlesnake is 2.44 m long. How long is the snake in cm? 2)244 cm 2.44 m x 100 cm = 244 cm 1 m

LecturePLUS Timberlake6 Learning Check CF2 How many seconds are in 1.4 days? Unit plan: days hr min seconds 1.4 days x 24 hr x ?? 1 day

LecturePLUS Timberlake7 Solution CF2 Unit plan: days hr min seconds 1.4 days x 24 hr x ?? 1 day 2 SF Exact 1.4 day x 24 hr x 60 min x 60 sec 1 day 1 hr 1 min = 1.2 x 10 5 sec

LecturePLUS Timberlake8 Unit Check What is wrong with the following setup? 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min

LecturePLUS Timberlake9 Unit Check 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min Units = day 2 /hr 2 Not the final unit needed

LecturePLUS Timberlake10 Learning Check CF3 An adult human has 4650 mL of blood. How many gallons of blood is that? Unit plan: mL qt gallon Equalitites:1 quart = 946 mL 1 gallon = 4 quarts Your Setup:

LecturePLUS Timberlake11 Solution CF3 Unit plan: mL qt gallon Setup: 4650 mL x 1 qt x 1 gal = 1.23 gal 946 mL 4 qt 3 SF 3 SF exact 3 SF

LecturePLUS Timberlake12 List 4 or more things to remember when you are getting ready to work a problem. Compare your list with another student. Add to your list, if necessary. Steps to Problem Solving

LecturePLUS Timberlake13 Steps to Problem Solving Read problem Identify data Write down a unit plan from the initial unit to the desired unit Select conversion factors Change initial unit to desired unit Cancel units and check Do math on calculator Give an answer using significant figures

LecturePLUS Timberlake14 A friend needs to know the length of a ski pole in mm. The length is given in feet. Write a short paragraph of 3 to 4 complete sentences describing how you would change from one unit to the other. (Don't use any numbers at this time.) Read your paragraph to a neighbor.

LecturePLUS Timberlake15 Learning Check CF4 If the ski pole is 3.0 feet in length, how long is the ski pole in mm?

LecturePLUS Timberlake16 Solution CF4 3.0 ft x 12 in x 2.54 cm x 10 mm = 1 ft 1 in. 1 cm

LecturePLUS Timberlake17 Learning Check CF5 If your pace on a treadmill is 65 meters per minute, how many seconds will it take for you to walk a distance of 8450 feet?

LecturePLUS Timberlake18 Initial 8450 ft x 12 in. x 2.54 cm x 1 m 1 ft 1 in. 100 cm x 1 min x 60 sec = 2400 sec 65 m 1 min final (2 SF) Solution CF5

LecturePLUS Timberlake19 Using Percent (% ) % = Parts x 100 Whole % = Number (%) of Items x Items

LecturePLUS Timberlake20 Percent (%) as a Conversion Factor Select a unit (mass, volume, etc.) Write the % value in the numerator Write 100 of the same unit for the denominator = 25 unit of mass of sugar 100 unit of mass of candy

LecturePLUS Timberlake21 Example: A candy is 25% (by mass) sugar. Select a unit of mass in grams 25 g sugar and100 g candy 100 g candy 25 g sugar in milligrams 25 mg sugar and 100 mg candy 100 mg candy 25 mg sugar

LecturePLUS Timberlake22 Learning Check CF6 Sea water is 3.1%by mass salt (NaCl). Write the factors for the % using (1) kg and (2) lb (1) _______________ and ______________ (2) _______________ and ______________

LecturePLUS Timberlake23 Solution CF6 Sea water is 3.1% salt (NaCl). Write factors for % using (1) kg and (2) lb (1) 3.1 kg NaCl and 100 kg sea water 100 kg sea water 3.1 kg NaCl (2) 3.1 lb NaCl and 100 lb sea water 100 lb sea water 3.1 lb NaCl

LecturePLUS Timberlake24 Learning Check CF7 How many lb of sugar are in 120 g of candy if the candy is 25% (by mass) sugar?

LecturePLUS Timberlake25 Solution CF7 How many lb of sugar are in 120 g of candy if the candy is 25%(by mass) sugar? % factor 120 g candy x 1 lb candy x 25 lb sugar 454 g candy 100 lb candy = lb sugar