1 / 21

Conversions Significant Digits Rounding

Conversions Significant Digits Rounding. Significant Digits. Significant Digits. What is the definition of significant? How is “Digit” used in this phrase?. Significant Digits Can be:. N onzero digits 654 Z eros between nonzero digits 6042

nani
Download Presentation

Conversions Significant Digits Rounding

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Conversions Significant DigitsRounding

  2. Significant Digits

  3. Significant Digits • What is the definition of significant? • How is “Digit” used in this phrase?

  4. Significant Digits Can be: • Nonzero digits 654 • Zeros between nonzero digits 6042 • Zeros to the right of a nonzero digit and to the left of a decimal 4230. • Zeros to the right of a nonzero digit and to the right of a decimal 0.30

  5. Digits That are Never Significant: • Zeros to the left of decimal in values less than one 0.82 • Zeros to the right of decimal and to the left of the first nonzero digit 0.082

  6. Significant Digits Exceptions • Exact Conversion factors are considered to have unlimited significant digits 1000 mm = 1 m • Counting numbers have unlimited sig digs 6 doughnuts

  7. Significant Digits Practice • How many significant digits? • 1044 (4) • 10 (1) • 10. (2) • 0.10 (2) • 130 (2) • 1040 (3) • 0.12 (2) • 1060220 (6) • 0.3000 (4) • 1040. (4)

  8. Scientific Notation Why do we use an elevator? Why is a fax machine an office requirement? Why do we drive a car to work? Which is faster, a whisk or a blender? Why do we use a microwave oven?

  9. Scientific Notation Why should you use scientific notation? When should you use scientific notation?

  10. Avagadro’s Number • 602200000000000000000000 • This number represents the number of molecules in one “MOLE” of material. BUT • You have to know the formula of the material. • 602000000000000000000000 • Write it five times!

  11. Avagadro’s Number • 602000000000000000000000 • Want to write it five more times? • Lets write it again like this: • 6.022 X 1023 • This is called scientific notation. • Write this one five times! • Which would you rather write? • WHY?

  12. Adding or Subtracting with Sci. Not. • 6.022 x 1023 + 4.522 x 1022 • These numbers cannot be added as written. • The exponents must be the same in order to add or subtract. • = 6.022 x 1023 + 0.4522 x 1023 • = 6.474 x 1023

  13. Multiplyingwith Sci. Not. • 6.022 x 1023 x 2.37 x 1022

  14. Situation • I’m making omelets for a bunch of people. I need a lot of eggs. • What is “a dozen” eggs? • Express a dozen eggs in scientific notation: • 1.2 X 101 • Can you think of two mathematical ways to express TWO dozen eggs (use scientific notation)? • 2 x (1.2 X 101) • (1.2 X 101) + (1.2 X 101)

  15. To Remember about SciNot • Properly expressed, a SciNot value will have one nonzero digit to the left of the decimal. • In converting to SciNot: • 165467 • For each place you move the decimal left, increase the exponent by 1 • = 1.65467 X 105 (6 Significant Digits) • In converting to SciNot: • 0.00002350 • For each place you move the decimal right, decrease the exponent by 1 • = 2.350 X 10-5 (4 Significant Digits)

  16. Conversions • The language of chemistry is mathematical and verbal. • The typical measurement system of chemistry is the SI system. • Length = Meters (m) • Mass = Grams (g) • Volume = Liters (L) • Temperature = Kelvins (k) or degrees celsius °C • Pressure = Pascals (Pa) or Atmospheres (atm) • There are more conversions that we will cover later.

  17. Conversions - II • Metric conversions – Remember this acronym: • KHDmdcm g L King Hector Died monday drinking chocolate milk Use this acronym when converting from one metric unit to another metric unit.

  18. Conversions - III • Example: • Convert 650 mL (milliliters) to L Liters K H D (L) d c m K H D (L) d c m You have to move 3 places left. Since you have to Jump 3 places to the left, move the decimal point 3 digits to the left. 6 5 0 . = 0.650 L

  19. Conversions - IV • Example II: • Convert 7.25 Km (Kilometers) to m (meters) K H D (m) d c m K H D (L) d c m You have to move 3 places right. Since you have to Jump 3 places to the right, move the decimal point 3 digits to the right and add a zero. 7 . 2 5 0 . = 7250. m

  20. Conversions - V • Try! Convert 72.5 g to mg • Answer: 72,500 mg • Try one more: Convert 26 HL to dL • Answer: 26,000 dL

  21. Conversions - Practice • Convert 65 mg to g • How many Decagrams are in 5 grams? • How many kilograms are in 7588 grams? • How many deciliters are in 2.7 liters? • How many km are in 102,000 cm?

More Related