MATTER & MEASUREMENTS

Learning

Properties & Types of Matter

Changes

Math & Metric System; Numbers

Precision/Accuracy

E: energy subst: substance rxn: reaction w/: with w/o: without : change amt: amount

Learning Chemistry

Requires you to bring together new concepts & devel new skillsNeed to devel good study habitsDon’t FALL BEHINDFocus your studyGood notesText material before classReview material before classLearn language of ChemMake use of resources

Ch. 1lays foundation to your study

Chem all around impacts our lives; health care, environment, our needs

Other fields bio, geo, engr, arts, ag

MATTERmass & vol

3 States Solid - def shape, def vol, not compressibleLiquid - def vol, shape of container, not compressibleGas -vapor, not def shape/vol, highly compressible

S: molecules heldtightly in fixed

position

G: molecules far apart,no specific arrangement,move high speed, collide

w/ each other & wall

L: molecules closetogether in random

motion

Physical Change state (s-l-g) but not composition phy appearance

What effect does incr Temp cause?

Classification diagram, pg 11

MATTERmass & vol

HETROGENEOUS Mixture diff throughout

HOMOGENEOUS same throughout

MIXTURE SOLN

PURE SUBST

VariableComposition

g, l, s

uniformthru-out

NO YES

NO YES

minerals

liquids

solnLi2CO3

gasCH3CH2CH3

dry cmpdAgNO3

oceantable saltNaCl

PURE SUBST

ELEMENTnot broken down

CMPDbroken down

madesimplier

NO YESp.table

H2O ---->H2 + O2

PROPERTIES

Extensive \ Intensive additive non-

What examples of 2 diff subst can be combined?#1: 50 ml @ 25oC #2: 100 ml @ 50oC

volume

Physical \ Chemical Changessame subst new substmix amts new propssep phy sep chemreturn not return

METRIC SYSTEMDimensional Analysis/Factor Label

500 yd to inches? conversion factors: 1 yd = 36 in 1 yd = 3ft & 1 ft = 12 in

factor-label method UNITGIVEN

UNIT toconversion*1 UNITGIVEN

in yd 1in 36 *

1yd 500

look at the“unit labels”

in ft 1in 12

yd 1ft 3 *

1yd 500

Base Units length: meters, mmass: grams, gvolume: liters, l (L)

Relationship:

1 ml = 1 cm3

Mass Weight

Based on quantity of matter presentNot affected by gravity

Affected by gravitational force

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; ; 10-10 A o pico; p; 10-12

SMALLER: down

scale, move dec. pt. left LARGER: up scale,

move dec. pt. right

10-410-5

10-710-8 10-11

How many km is 745.26 cm?

100,000cm

km 1 * 1

cm 745.260.0074526

1.5*106 L to kL?

L 1

kL 9-10*1 * 1

L 610*1.5

L 910*1

kL 1 * 1

L 610*1.5

TEMPERATURE SCALES• Fahrenheit, Celsius, Kelvin

BOILING PT. FREEZING PT.

oF

oC

K

212o

100o

373.15o

32o

0o

273.15o

oF = (9/5 oC) + 32 oC = 5/9(oF - 32) K = 273.15 + oC

)cm (ml vol(g) mass Density

3or

mass perunit vol temp depend

GAS: g/L

table densities, pg 17

consider 2 Fe samples #1: 6 g @ 7.9 g/mL #2: 4 g @ 7.9 g/cm3

Which properties are intensive? mass or density

Measurements

exact number: all digit values known; definition or countdozen, 12 1 ft = 12 in 2.54 cm = 1 in

Where do they come from?

inexact: uncertainty in last digit value

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

8.00 ml

23.0600 km

4. Zeros before 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

500 500_

500_ _

?1 ?2 ?3

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

5. Zeros at the end of a whole number are sig. if a bar is over the zero; or decimal pt shown

500. ?3

OPERATIONS

Add / Subtract Count decimal places (least)

161.032 5.6+ 32.4524

32.5437- 3.54

??

?

?

Multiply / Divide Count sig. figures

152.06* 0.24

5.6 * 103

8.50

?36.4944

?36

= ?658.8235294 => ?660

or ?6.60*102

ACCURACY & PRECISION

Accuracy

• How close data points to “true” value

• 7.96 7.92 8.02

• 7.96 4.02 24.87

Accuracy

• Closeness of set of collected data to the “correct” or most probable value

ACCURACY & PRECISION

Precision

• Closeness of set of collected data among the data itself

Precision

• How close data points are to each other; grouped

• 0.997 0.999 1.003

• 1.325 0.046 5.263

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Poor accuracy & precision

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Good precision & Poor accuracy

Good accuracy & precision

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