userdata-paziras-Chem101-Chap_01B

27cmandheight614cm v d 2 h 1272614 77779598cm

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Unformatted text preview: re than · THE CORRECT ANSWER IS : 15 Chemistry 101 Chapter 1 ROUNDING OFF · If the rounded digit is <5, the digit is simply dropped. · If the rounded digit is ³5, the digit is increased. 51.234 ® 51.2 51.38, 51.359, 51.3503 ® 51.4 Example 1: rounded off to 3 SF 7.7776 g ¾¾¾¾¾¾¾¾¾> 124 g rounded off to 2 SF ¾¾¾¾¾¾¾¾¾> 7.78 g 120 g rounded off to 2 SF 14.4444 % ¾¾¾¾¾¾¾¾¾> 0.02317 g (7 > 5) rounded off to 2 SF ¾¾¾¾¾¾¾¾¾> (4 < 5) 14 % (4 < 5) 0.023 g (1 < 5) · When performing calculations with multiple steps, it is often better to carry extra digits and round in the final step. Example 2: Calculate the volume of a cylinder, given diameter = 1.27 cm and height = 6.14 cm. V = π d 2 h π (1.27)2 (6.14) = = 7.7779598 cm 3 ¾Roun¾ 3 SF ® 7.78 cm 3 ¾ d to ¾ ¾ 4 4 16 Chemistry 101 Chapter 1 SI UNITS · International System of units adopted in 1960 · Is an improved metric system · Has the major advantage of being a decimal system (all conversion factors are multiples of 10) SI units consist of: 1. SEVEN BASE UNITS 1. 2. 3. 4. 5. 6. 7. Abbreviation m kg s K mol A cd Quantity Unit Length meter Mass kilogram Time second Temperature Kelvin Amount of substance mole Electric current ampere Luminous intensity candela 2. MANY DERIVED UNITS 1. 2. 3. 4. 5. 6. 7. Quantity Speed = Length/Time Volume =(Length)3 Density = Mass/Volume Acceleration = speed/time Force = Mass x Acc Pressure = Force/Area Energy = Force x Length Unit meter/second (meter)3 3 kg/m m/s2 kg m/ s2 2 kg/m s 2 kg m / s2 17 Abbreviation m/s 3 m 3 kg/m 2 m/s N (Newton) Pa (Pascal) J (Joule) Chemistry 101 Chapter 1 SI BASE UNITS AND PREFIXES SMALLER UNITS ­12 10 ½½ pico p LARGER UNITS BASE 10 10 10 UNIT ½½½½½½½½½½½½½ nano micro milli centi deci n m m cm dm ­9 ­6 ­3 3 6 9 10 10 10 ½ ½ ½ ½ ½ ½ ½ kilo mega giga k M G MEANING: 3 1m = 1,000 mm = 10 mm OR 1mm = 0.001 m = ­ 10 3 m 3 1mm = 1,000 mm = 10 mm OR ­ 1 mm = 0.001 mm = 10 3 mm 6 1m = 10 mm OR ­ 1 mm = 10 6 m ­ 1m = 10 6 mm ¾¾¾¾> IS FALSE A...
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This document was uploaded on 03/18/2014 for the course CHEM 101 at Los Angeles Mission College.

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