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