METRIC SYSTEM & NUMBERS

Unit Conversions in metric units

Temp. scales

Scientific notation

Significant figures

1 lb =454g 1 in = 2.54 cm 1 gal = 3.79 l F = 1.8* oC +32

C = 5/9*(oF-32 )

K = 273.15 + oC

SI Units: International units

Mass --> g vol--> m3 length--> m temp-->K time-->s energy-->J

1 ml = 1 cm3

1 cm1

cm

1 cm

BASE: gram, meter, literg, m, l

100 = 1

decid 10-1

centic 10-2

millim 10-3

micro 10-6

dekada 101

hectoh 102

kilok 103

Mega; M; 106 Giga; G; 109 Tera; T; 1012

nano; n; 10-9 angstrom; ; 10-10Ao

pico; p; 10-12

SMALLER: down scale,

move dec. pt. left

LARGER: up scale,

move dec. pt. right

10-410-5

10-7

10-8 10-11

10

1

1001000

.1

.01

.001

How many to makeA “base” unit

CONVERSIONS Use “Dimensional Analysis”-- Factor Label --

conversion*1

GIVEN Look at the “unit labels”

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

4. Calculate answer, also, use the proper “label” sig. figures

ft 3yd 1 *

1ft 526.48 yd175.49

FORM:

How many km is 745.26 cm?

100,000cm

km 1 * 1

cm 745.26 km0.0074526

7.4526 * 102 cm * 1 m

* 1 km

1 102 cm 103 m

OR

= 0.0074526 km 7.4526 * 10-3 km

SCIENTIFIC NOTATION

FORM __ . __ __ __ __ * 10 +/- exp

6.25 * 104

9.146 * 10-7

6.25 * 10000 = 62500

0.0000009146

“+” exponent, movedecimal point to right

“-” exponent, movedecimal point to left

any non-zero single digit

SIGNIFICANT FIGURES

1. All nonzero digits are significant 5.37 cm 4.293g

2. Zeros between nonzero digits are sig. 106 ml 1.02 L

3. Zeros to the right of the dec. pt. at the end of a number are sig.

8.00 ml

23.0600 km

4. Zeros preceding the 1st nonzero digit in a number are not sig.

0.002 g 0.060 * 10-3 mm 0.00000725 L

3 4

3 3

3

6

1 2 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_

500_ _

1 2 3

EXACT NUMBERSNumbers 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 numberw/ the least number of sig. figs.

ADD / SUBTRACT

251.708 7.6+ 23.4524

48.3737- 4.37

282.7604

282.8

44.0037

44.00

MULTIPLY / DIVIDE

152.06* 0.24

5.6 * 103

8.50

36.4944

36

658.82353 => 660

6.6 * 102

660This could alsobe used withoutplacing a bar overthe zero

TEMPERATURE SCALES•Fahrenheit, Celsius, Kelvin

BOILING PT. water

FREEZING PT. water

oF oC K

212o 100o 373.15o

32o0o 273.15o

( K = 273.15 + oC )

ROOM TEMP. air 68o 20o 293.15o

C = 5/9*(oF-32 )( F = 1.8* oC +32)

MASS:

WEIGHT:

Based on quantity of matter presentNot affected by gravity

Affected by gravitational force

Earth:

Mass = 200 lbsWeight = 200 lbs

Moon:

Mass = 200 lbsWeight = 35 lbs

Less gravitational pull 1/6 than earth

Mass = 200 lbsWeight = 35 lbs

DENSITYDENSITY

)cm (ml vol(g) mass Density

3or

Equation

Density: represents mass per unit volume

1 ml = 1 cm3Relationship:

vm D

Also, keep in mind that

vm D Know mass & vol, find Density

Know Density & vol, find mass

m = D * v

Know Density & mass, find volume

Dm v

Label: g/ml or g/cm3

Label: g

Label: ml or cm3

liquid solid

Specific Gravity

density of subst. divided by density of water

Unitless number: density w/o label

DH2O = ml

g 1spec. gravity = 1

What is Energy????

-Capacity or ability to do work, cause -Capacity or ability to do work, cause

some type of change some type of change

WORK??WORK??

-when a force affects the motion of-when a force affects the motion of

an object, work is donean object, work is done

ENERGY • -Definition

• -Types of

• -Law of

Two Main Types of E

POTENTIAL & KINETICPotential 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.

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)

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

HEAT:

TEMPERATURE:

-- 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

-- Measure of degree of hotness or coldness of matter

EXOTHERMIC: Release of HEAT energy

ENDOTHERMIC: Absorbs HEAT energy

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

Specific heat g.oCcal

cal = * *g.oCcal

1oC

1g

0.255 kg of molten Au is cooled from 1246.3 oC to 1175.62 oC. The spec. heat is 0.031How much heat is involved?

0.250 kg = 250 g

temp. change = 1175.62 - 1246.3 = -70.68 = -70.7oC

Specific heat = g.oCcal 0.031

g.oC0.031cal

Heat (cal) = 255 g * * -70.7oC

= -558.884 = -559 cal