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METRIC SYSTEM & NUMBERS

1 cm. 1 cm. 1 cm. METRIC SYSTEM & NUMBERS. Unit Conversions in metric units. F = 1.8 * o C +32. 1 lb =454g 1 in = 2.54 cm 1 gal = 3.79 l. Temp. scales. Scientific notation. C = 5/9*( o F-32 ). K = 273.15 + o C. Significant figures. SI Units: International units.

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METRIC SYSTEM & NUMBERS

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  1. 1 cm 1 cm 1 cm METRIC SYSTEM & NUMBERS Unit Conversions in metric units F = 1.8* oC +32 1 lb =454g 1 in = 2.54 cm 1 gal = 3.79 l Temp. scales Scientific notation C = 5/9*(oF-32 ) K = 273.15 + oC Significant figures SI Units: International units Mass --> g vol--> m3 length--> m temp-->K time-->s energy-->J 1 ml = 1 cm3

  2. o angstrom; ; 10-10 A nano; n; 10-9 pico; p; 10-12 10-11 10-8 10-7 10-6 How many to make A “base” unit micro 10-5 10-4 1000 10-3 m milli 100 c centi 10-2 SMALLER: down scale, move dec. pt. left 10 10-1 d deci BASE: gram, meter, liter 1 100 = 1 g, m, l .1 da 101 deka .01 hecto 102 h LARGER: up scale, move dec. pt. right k kilo .001 103 Mega; M; 106 Giga; G; 109 Tera; T; 1012

  3. Use “Dimensional Analysis” -- Factor Label -- CONVERSIONS Look at the “unit labels” FORM: You are asked to convert 526.48 feet to ??? Yards. 1. Identify the GIVEN: 526.48 ft 2. Place the GIVEN in fraction form over “1” 3. Set up the conversion factor(s): 1 yd = 3 ft • Calculate answer, also, use the proper “label” • sig. figures 175.49 yd

  4. How many km is 745.26 cm? 0.0074526 km OR 7.4526 * 102 cm*1 m *1 km 1 102 cm 103 m = 0.0074526 km 7.4526 * 10-3 km

  5. SCIENTIFIC NOTATION FORM __ . __ __ __ __ * 10 +/- exp any non-zero single digit 9.146 * 10-7 6.25 * 104 0.0000009146 “-” exponent, move decimal point to left 6.25 * 10000 = 62500 “+” exponent, move decimal point to right

  6. SIGNIFICANT FIGURES 5.37 cm 3 4.293g 4 1. All nonzero digits are significant 2. Zeros between nonzero digits are sig. 106 ml 3 1.02 L 3 3. Zeros to the right of the dec. pt. at the end of a number are sig. 8.00 ml 3 23.0600 km 6 4. Zeros preceding the 1st nonzero digit in a number are not sig. 0.002 g 1 0.060 * 10-3 mm 2 0.00000725 L 3 5. Zeros at the end of a number but to the left of the dec. pt. are sig. if a bar is over the zero _ _ _ 500 500 1 2 500 3

  7. EXACT NUMBERS Numbers from definitions or count of objects. These are not considered when determining sig. figures, they contain “no uncertainty” OPERATIONS Add / Subtract Result is the same number of decimal places as the number w/ the least number of decimal places Multiply / Divide Result rounded to the same number of sig. figs. as the number w/ the least number of sig. figs.

  8. ADD / SUBTRACT 251.708 7.6 + 23.4524 48.3737 - 4.37 282.7604 44.0037 282.8 44.00

  9. MULTIPLY / DIVIDE 5.6 * 103 8.50 152.06 * 0.24 36.4944 658.82353 => 660 36 6.6 * 102 660 This could also be used without placing a bar over the zero

  10. TEMPERATURE SCALES • Fahrenheit, Celsius, Kelvin ( F = 1.8* oC +32) C = 5/9*(oF-32 ) ( K = 273.15 + oC ) K oF oC BOILING PT. water 212o 100o 373.15o FREEZING PT. water 32o 0o 273.15o ROOM TEMP. air 68o 20o 293.15o

  11. Based on quantity of matter present Not affected by gravity MASS: Mass = 200 lbs Weight = 35 lbs Affected by gravitational force WEIGHT: Earth: Moon: Mass = 200 lbs Weight = 35 lbs Less gravitational pull 1/6 than earth Mass = 200 lbs Weight = 200 lbs

  12. DENSITY Equation Density: represents mass per unit volume Also, keep in mind that 1 ml = 1 cm3 Relationship:

  13. Know mass & vol, find Density Label: g/ml or g/cm3 solid liquid Know Density & vol, find mass m = D * v Label: g Know Density & mass, find volume Label: ml or cm3

  14. Specific Gravity density of subst. divided by density of water Unitless number: density w/o label DH2O = spec. gravity = 1

  15. ENERGY What is Energy???? • -Definition • -Types of • -Law of -Capacity or ability to do work, cause some type of change WORK?? -when a force affects the motion of an object, work is done

  16. Two Main Types of E POTENTIAL & KINETIC Potential E -stored E -E that matter possesses because of its position or composition Kinetic E -E of matter in motion -P.E. converted to K.E.

  17. CHEMICAL-Contained in all matter-P.E. from the composition Other Forms -Radiant, includes Visible light, IR, UV, Microwave, X-Rays -Heat, Electrical -Solar, Atomic (Nuclear)

  18. Law of Conservation of E -Total amount of E in universe is constant -E is neither created nor destroyed; -changes form, may not be useful

  19. HEAT: -- Most common form of E -- The amt. of internal E in matter -- Amt. of E transferred from one subst. to another subst. when a temp. diff. is present TEMPERATURE: -- Measure of degree of hotness or coldness of matter EXOTHERMIC: Release of HEAT energy ENDOTHERMIC: Absorbs HEAT energy

  20. Specific heat cal = * * calorie: Amt. of heat E required to raise 1 g of water 1 oC 1 Cal = 1000 cal = 1 kcal Amt. of heat required to raise 1 g or subst. 1 oC ref. is water = 1 cal / g.oC Heat (cal) = Mass * spec. heat * temp. change Tfinal - Tinitial

  21. Specific heat = Heat (cal) = 255 g * * -70.7oC 0.255 kg of molten Au is cooled from 1246.3 oC to 1175.62 oC. The spec. heat is 0.031 How much heat is involved? 0.250 kg = 250 g temp. change = 1175.62 - 1246.3 = -70.68 = -70.7oC -559 cal = -558.884 =

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