Do now: read chapter 1.6

Unit 1-3 SI units

How much does it cost?UNITS MATTER!!

The Nature of Measurement

Part 1 - numberPart 2 - scale (unit)

Examples: 20 grams6.63 x 10-34 seconds

A Measurement is a quantitative observation consisting of TWO parts

The Fundamental SI Units (le Système International, SI)

Physical Quantity Name Abbreviation

Mass kilogram kg

Length meter m

Time second s

Temperature Kelvin K

Electric Current Ampere A

Amount of Substance mole mol

Luminous I ntensity candela cd

The three major temperature scales.

5

TK = TC + 273.15

TC = TK – 273.15

Temperature scales Celsius scale

based on freezing and boiling points of water (0 oC – 100 oC)

Kelvin scale based on absolute zero (0 K) temperature at

which particles are at lowest possible energy NO negative numbers

K = oC + 273

oC = K – 273

Converting Between Celsius & Fahrenheit

TC = (TF – 32)X 5/9

TF = TC x 9/5 + 32You don’t need to memorize the conversion

between TC and TF

SI Prefixes Common to Chemistry

Prefix Unit Abbr. ExponentKilo k 103

Deci d 10-1

Centi c 10-2

Milli m 10-3

Micro 10-6

SI Prefixes1 T(base) = 1 000 000 000 000(base) = 1012 (base)

1 G(base) = 1 000 000 000 (base) = 109 (base)

1 M(base) = 1 000 000 (base) = 106 (base)

1 k(base) = 1 000 (base) = 103 (base)

1 h(base) = 100 (base) = 102 (base)

1 da(base) = 101 (base)

1 (base) = 1 (base)

1 d(base) = 10-1 (base)

1 c(base) = 10-2 (base)

1 m (base) = 10-3(base)

1 µ(base) = 1 000 000 (base) = 10-6(base)

1 n(base) = 1 000 000 000 (base) = 10-9(base)

1 p(base) = 1 000 000 000 000(base) = 10-12(base)

The

Great

Man

King

Henry

Died

By

Drinking

Chocolate

Milk

Monday

Night

Partying

Tera-

Giga-

Mega-

Kilo-

Hecto-

Deka-

Base

Deci-

Centi-

Milli-

Micro-

Nano-

Pico-

mega- M 106

deci- d 10-1

centi- c 10-2

milli- m 10-3

Prefix Symbol Factor

micro- 10-6

nano- n 10-9

kilo- k 103

BASE UNIT --- 100

giga- G 109

deka- da 101

hecto- h 102

tera- T 1012

Dec

imal

mo

ve le

ft

Dec

imal

mo

ve r

igh

tSI Prefix Conversions

pico- p 10-12

Prefix conversiongmL

10-1 10-2 10-3101102103

Baseunit

deci centi millidekahectokilo

Conversions between prefixes are merely a matter of moving a decimal point. The “base unit” means the you have a quantity (grams, meters, Liters, etc without a

prefix.

Metric ConversionsgmL

10-1 10-2 10-3101102103

Baseunit

deci centi millidekahectokilo

Example #1: Convert 18 liters to milliliters

18 L

1 2 3

18 liters = 18 000 milliliters

Metric ConversionsgmL

10-1 10-2 10-3101102103

Baseunit

deci centi millidekahectokilo

Example #2: Convert 450 milligrams to grams

123

450 mg450 mg = 0.450 g

Metric ConversionsgmL

10-1 10-2 10-3101102103

Baseunit

deci centi millidekahectokilo

Example #3: Convert 20 kilograms to milligrams

20 kg1 2 3 4 5 6

20 kg = 20 000 000 mg

Derived SI units

Volume= (length)3

SI unit of V: m3

Commonly used units of V:Liter(L)= dm3

Milliliter(ml)=cm3

a. cm to m

b. m3 to L

c. ns to s

d. kg to g

SI Prefix Conversions-concept check

SI Prefix Conversions-concept check

1) 20 cm = ______________ m

2) 0.032 L = ______________ mL

3) 45 m = ______________ m

HandoutDue next class.

Homework