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Measurement and the Factor Label Method Chem 140.

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Presentation on theme: "Measurement and the Factor Label Method Chem 140."— Presentation transcript:

1 Measurement and the Factor Label Method Chem 140

2 SI base units SI (Système Internationale d’Unites) adopted in 1960 Contains 7 base units: length: meter (m) mass: kilogram (kg) time: second (s) electrical current: ampere (A) temperature: kelvin (K) amount of substance: mole (mol) Luminous intensity: candela (Cd)

3 Know Your Metric Prefixes prefix value (exp.) value tera- (T) ,000,000,000,000 giga- (G)10 9 1,000,000,000 mega- (M)10 6 1,000,000 kilo- (k)10 3 1,000 deci- (d) centi- (c) milli- (m) micro- (µ) nano- (n) pico- (p)

4 Derived units: speed meter… …in 1 second 1 m s -1 speed (velocity)

5 Derived units: acceleration Start 0 speedometer m s -1

6 Derived units: acceleration After 1 second 0 speedometer m s meter per second per second 1 m s -2

7 Acceleration …in 5 s 50 m/s… …to 20 m/s… acceleration = change in speed time = –30 m s  1 5 s = – 6 m s2s2

8 Other derived units Force (newton, N): kg m s -2 Work, energy (joule, J): kg m 2 s -2 Power (watt, W): kg m 2 s -3 Pressure (pascal, Pa): kg m -1 s -2 Volume: m 3 Density: kg m -3

9 Metric to English (Without Too Much Memorizing) 1 inch = 2.54 cm 1 gallon (US) = 231 in 3 1 lb. = g °C = (°F – 32) x 5/9 °F = (°C x 9/5) inch = 2.54 cm 1 gallon (US) = 231 in 3 1 lb. = g °C = (°F – 32) x 5/9 °F = (°C x 9/5) + 32 You can figure out many other conversions from these basic (exact) ones You can figure out many other conversions from these basic (exact) ones

10 Factor-label method (on board) Convert 65 mph to m s -1, using the information on the previous slide, and english-to-english conversions. A car gets 35 mpg fuel mileage. What’s this in km/L? cubic meters to cm 3

11 Volume What is the volume of a cube 0.1 m (1 dm) on a side, in m 3 ? m 3 Also called a “liter” (L)

12 Volume What is the length of each side of a cube with a volume of 1 mL? L = m 3 = (0.01) 3 m 3 = 0.01 m (1 cm) on a side

13 1 m 3 = 1 kL Length and Volume dm 3 = 1 L 1 Mg of water 1 kg of water 1 cm 3 = 1 mL 1 g of water

14 Volume and Mass LinearCubicLitersWater 1 m10 0 m1 m m 3 1 kL10 3 L1 Mg 1 dm10 -1 m1 dm m 3 1 L10 0 L1 kg 1 cm10 -2 m1 cm m 3 1 mL10 -3 L1 g 1 mm10 -3 m1 mm m 3 1 µL10 -6 L1 mg


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