CH 2 MEASUREMENT I Units of Measurement I

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CH. 2 - MEASUREMENT I. Units of Measurement I II III (p. 33 -

CH. 2 - MEASUREMENT I. Units of Measurement I II III (p. 33 - 39)

A. Number vs. Quantity Ø Quantity - number + unit UNITS MATTER!!

A. Number vs. Quantity Ø Quantity - number + unit UNITS MATTER!!

B. SI Units Quantity Symb Base Unit Abbre ol v. l Length meter m

B. SI Units Quantity Symb Base Unit Abbre ol v. l Length meter m Mass m kilogram kg Time t second s Temp T kelvin K Amount n mole mol

B. SI Units Prefix mega- Symbol M Factor 106 kilo- k 103 BASE UNIT

B. SI Units Prefix mega- Symbol M Factor 106 kilo- k 103 BASE UNIT --- 100 deci- d 10 -1 centi- c 10 -2 milli- m 10 -3 micro- 10 -6 nano- n 10 -9 pico- p 10 -12

C. Mass vs Weight Ø Mass -- amount of “stuff” with volume Ø Ø

C. Mass vs Weight Ø Mass -- amount of “stuff” with volume Ø Ø that is compared to a standard. Weight -- effect of gravity on mass. Balance measures mass by “canceling” effect of gravity. Scale measure weight & gravity. Which one changes? Where?

D. Derived Units Ø Combination of base units. 1 cm 3 = 1 m.

D. Derived Units Ø Combination of base units. 1 cm 3 = 1 m. L w length 1 dm 3 = 1 L Ø Volume (m 3 or cm 3) Ø Density (kg/m 3, g/cm 3, or g/ml) w mass per volume M D= V

Mass (g) E. Density Volume (cm 3)

Mass (g) E. Density Volume (cm 3)

F. Density Ø An object has a volume of 825 cm 3 and a

F. Density Ø An object has a volume of 825 cm 3 and a density of 13. 6 g/cm 3. Find its mass. GIVEN: WORK: V = 825 cm 3 D = 13. 6 g/cm 3 M=? M = DV M = (13. 6 g/cm 3)(825 cm 3) M = 11, 200 g

G. Density Ø A liquid has a density of 0. 87 g/m. L. What

G. Density Ø A liquid has a density of 0. 87 g/m. L. What volume is occupied by 25 g of the liquid? GIVEN: WORK: D = 0. 87 g/m. L V=? M = 25 g V=M D V= 25 g 0. 87 g/m. L V = 29 m. L