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## CH. 2 - MEASUREMENT

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**CH. 2 - MEASUREMENT**III. Unit Conversions (p. 40 - 42) C. Johannesson**To the left**or right? A. SI Prefix Conversions 1. Find the difference between the exponents of the two prefixes. 2. Move the decimal that many places. C. Johannesson**NUMBER**= UNIT A. SI Prefix Conversions 0.532 532 m = _______ km NUMBER UNIT C. Johannesson**mega-**kilo- k M 106 103 BASE UNIT deci- d --- 100 10-1 centi- c 10-2 milli- m 10-3 micro- 10-6 nano- n 10-9 pico- p 10-12 A. SI Prefix Conversions Prefix Symbol Factor move left move right C. Johannesson**1) 20 cm = ______________ m**2) 0.032 L = ______________ mL 3) 45 m = ______________ nm 4) 805 dm = ______________ km A. SI Prefix Conversions 0.2 32 45,000 0.0805 C. Johannesson**B. Dimensional Analysis**• The “Factor-Label” Method • Units, or “labels” are canceled, or “factored” out C. Johannesson**B. Dimensional Analysis**• Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel. 3. Multiply all top numbers & divide by each bottom number. 4. Check units & answer. C. Johannesson**B. Dimensional Analysis**• Lining up conversion factors: = 1 1 in = 2.54 cm 2.54 cm 2.54 cm 1 = 1 in = 2.54 cm 1 in 1 in C. Johannesson**qt**mL B. Dimensional Analysis • How many milliliters are in 1.00 quart of milk? 1 L 1.057 qt 1000 mL 1 L 1.00 qt = 946 mL C. Johannesson**lb**cm3 B. Dimensional Analysis • You have 1.5 pounds of gold. Find its volume in cm3 if the density of gold is 19.3 g/cm3. 1 cm3 19.3 g 1 kg 2.2 lb 1000 g 1 kg 1.5 lb = 35 cm3 C. Johannesson**in3**L B. Dimensional Analysis • How many liters of water would fill a container that measures 75.0 in3? 1 L 1000 cm3 (2.54 cm)3 (1 in)3 75.0 in3 = 1.23 L C. Johannesson**cm**in B. Dimensional Analysis 5) Your European hairdresser wants to cut your hair 8.0 cm shorter. How many inches will he be cutting off? 8.0 cm 1 in 2.54 cm = 3.2 in C. Johannesson**cm**yd B. Dimensional Analysis 6) Taft football needs 550 cm for a 1st down. How many yards is this? 1 ft 12 in 1 yd 3 ft 1 in 2.54 cm 550 cm = 6.0 yd C. Johannesson**cm**pieces B. Dimensional Analysis 7) A piece of wire is 1.3 m long. How many 1.5-cm pieces can be cut from this wire? 1 piece 1.5 cm 100 cm 1 m 1.3 m = 86 pieces C. Johannesson