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Matter

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Pure Substance                                                                   Mixture of

(homogeneous)                                                                    Substances

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Elements

(single substances)

(Iron, sulfur, carbon, H, oxygen
 

Compounds

(iron sulfide, water (H20)
 

Homogeneous mixture – uniform thru out (aka SOLUTION)
 

Heterogenous

mixtures
 
 

 

 

 

 

 

 


Atom: smallest particle of matter that can enter into a reaction

 

 

 

Observable properties

Atomic theory

Element:

Can’t be broken down

Only one kind of atom

Compound:

Fixed composition but can be broken down into elements

2 or more atoms in fixed combination

Mixture:

Variable composition of elements and/or compounds (can be separated physically into elements or compounds)

Variable assortment of atoms & molecules

 

HOMONUCLEAR DIATOMICS:  H, N, O, F, Cl, Br, I, At

(H2, N2, O2, F2, Cl2, Br2, I2, At2)

 

H2 = homonuclear diatomic molecule

HCl = heteronuclear diatomic molecule

 

Compound:  2 or more different atoms

 

CH2 = 1 Carbon, 4 Hydrogen atoms (methane) = COMPOUND

N2O5 = 2 atoms of Nitrogen, 5 of Oxygen = COMPOUND

 

 

 

 

Composition of clean, dry air:

78% Nitrogen

21% Oxygen

1% other gases (Argon, Carbon Dioxide)

 

SUBSTANCE

INHALED AIR

EXHALED AIR

Nitrogen

78%

75%

Oxygen

21%

16%

Argon

0.9%

0.9%

Carbon Dioxide

0.04%

4%

Water

0%

4%

 

Earth’s Crust:

49.5% Oxygen

25.7% Silicon (sand)

9.2 % Other

7.5% Aluminum

4.7% Iron

3.4% Calcium

 

BODY:  (80% water)

65% Oxygen

18% Carbon

10% Hydrogen

7% Other

 

 

Stairstep line separates the metals from nonmetals –

if an atom is on the “left” side of this stairstep, it’s more like METAL;

if atom is on the “right” side of the stairstep, it’s more NONmetal.

 

There’s only one liquid metal (mercury, Hg)

 

Quantity                                  Unit                 Symbol

Length                                      meter                m

Mass                                        kilogram           kg

Time                                         second             s

Temp                                       Kelvin              k

Amount of substance                mole                 mol

 

 

Atomic Number: the number of protons and electrons an atom has.

Ex:       Hydrogen: “1”

Helium: “2”

 

Atomic mass:  the mass of one mole of the element.

Ex:       Helium (He)has a mass of  4  (one mole of Helium weighs 4 grams)

            Carbon (C) has a mass of 12.01 (one mole of Carbon weighs 12.01 grams)
Prefixes:                     Abbrev.           Meaning                     AKA:                          Example:

Giga                             G                     1,000,000,000             109       (billion)

Mega                           M                     1,000,000                    106  

Kilo                              K                     1,000                           103                   1 km= 1 x 103 Meters

Hecto                           h                      100                              102

Deka                            da                    10                                10 (or 101)

 

   <<< UNIT>>>

 

Deci                             d                      .10                               10-1  

Centi                            c                      .01                               10-2  

Milli                              m                     .001                             10-3                  1 mg = 1 x 10-3 grams

Micro                           u                      .000001                       10–6  

Nano                            n                      .000000001                 10-9  

 

 

CONVERSIONS:

 

CONVERTING TEMPERATURES:

 

(Tc = temp, Celsius;  Tf = temp, Fahrenheit)

To get the Celsius temp:

Tc = 5/9 (Tf – 32)

To get the Fahrenheit temp:

Tf = (9/5 x Tc) + 32

 

 

MEASUREMENT CONVERSIONS:

1 oz = 29.6 ml (or, 0.0296 liter)

1 km = 0.621 miles

1 inch = 2.54 cm

1 lb = 454 grams

2.21 lbs = 1 kg

1 ml = 1 cm3

1 L = 1.06 qts

1 mile = 1.609 km  (and 5,280 feet)

1 gal = 3.786 liters

 

Density = w/v

 

 

THE SCIENTIFIC METHOD:

O, Hel. T.

 

1. Observation  (educated guess)

2. Hypothesis   (testing hypothesis)

3. Experiment

4. Laws

5. Theory  (an idea that’s been tested but not quite set in stone)

 

 

Chemical Properties                          Physical Properties

Flammability                                         Texture

Corrosiveness                                       Color

                                                            Melting point

                                                            Boiling point

 

 

 

ACCURACY:  When all darts are close to the bull’s eye

 

PRECISION:  When all darts are closely-grouped

 

 

Accuracy does not necessarily mean precision, nor vice-versa

 

 

 

Atoms                             Atoms                                    Molecules

GRAMS of B
 

GRAMS of A
 

Particles of B
 

Particles of A
 

Moles of A
 

Moles of B
 
                                      Elements                                                                        Molecules

 

 

 

 

 

                                                         Molar mass                       Molar mass

(atomic)
e- = electron  (orbits nucleus, has negative (“-“) charge.             More electrons = more  -

                                                                                                Less electrons = more ++

In nucleus
 
p+ = proton

no = neutron

 

 

 

Element: a substance that has only one kind of atom (can be any phase; solid, liquid or gas)

Compound: 2 or more elements together

            N2O = compound; SrF = compound; NaCl = compound;  NaHCO3 = compound

 

 

 

 

 

 

 

 

IONIC and COVALENT:

The way elements are bonded together.

 

IONIC: TAKE.  Demand. 

 

COVALENT: SHARE. Cool, commune, hippies.

 

Ionic compound: consists of positively and negatively charged ions.

                                    (Metal / Nonmetal bonding)

Covalent compound:  consists of cooperatively (covalent)-bonded atoms.

                                    (nonmetal / nonmetal bonding)

 

(METAL / METAL BONDING DOESN’T NATURALLY OCCUR, and

ISN’T PART OF THIS CLASS)

 

What comprises a covalent compound:  everything to the RIGHT of the “stairstep”

(NONMETAL - NONMETAL)

 

H2O, N2O, NO, NO2

HYDROGEN: A NONMETAL

 

Naming Covalent Compounds: (IONIC COMPOUNDS DO NOT EVER GET PREFIXES)

 

Prefix              # of Atoms

Mono               1

Di                     2

Tri                    3

Tetra                4

Penta                5

Hexa                6

 

 

“Official” naming:

            H2O = “dihydrogen monoxide” 

            NO = “mononitrogen monoxide  “

            (However:  never use mono as a first element prefix)

 

Oxide

Sulfide

Nitride

Chloride

Fluoride

Iodide

Bromide

 

 

P3N4 = “triphosophorous tetranitride”

 

CHCl  =  covalent

 

CBr4 = monocarbon tetrabromide – covalent

            (However:  never use mono as a first element prefix)

 

HYDROGEN: A NONMETAL

 

 

 

 

IONIC COMPOUNDS:  Metal & Nonmetal

Metals: generally POSITIVE

NONmetals:  generally NEGATIVE

 

Common Simple Cation & Anion:

 

CATion:  positively charged  

Anion:  negatively charged

 

ION:  an electrically charged atom or group of atoms

 

 

GROUP (or, “Family”) CHARGES

NOTE: Group 8 isn’t used. It’s happy. It has a filled shell. Has all the electrons it needs or wants (8).

 

Group 1A         Group 2A                     Group 5A         Group 6A         Group 7A  

 +1                     +2                                 -3                     -2                      -1

 

NOTE:  Electron is the tiniest part of the atom.

Neutron is the largest, then proton, then lastly, the smallest is the electron.

 

How does Ionic Bonding work?

 

Let’s make salt:

We only need one atom of Sodium (Na)  and one atom of Chlorine (Cl)

 

NaCl

 

Na has a +1 charge, and Cl has a –1 charge.

Boom!  Match made in heaven!

 

How many Chlorines do we need if we want to hook Cl up with Mg (magnesium)?

TWO!

Why?

Mg has a +2 charge.  Since Cl has a –1 charge, we need TWO Cl’s to round out the shell for Mg.

Here’s the formula:  MgCl2

 

Mg with its +2 charge only needs ONE O atom because O has a –2 charge:

MgO  (magnesium oxide)

 

Now, to complicate things:

Nitrogen has a –3 charge, and if we want to hook it up to Mg, how do we do that?

 

Mg+2  and N-3

 

We cheat.  We cross multiply -  and see that we need 2 Mg’s to make +6 and 2 N’s to make -6

Like this:

                        Mg3N2


Na2O = sodium oxide  (we need 2 Na’s to hook up to O, because Na has a –1 charge and O has a –2 charge)

 

 

 

 

ELECTRONEGATIVITY:

            Nonmetals are more electronegative than metals.

 

 

 

SCIENTIFIC NOTATION

 

If there is no decimal point, the zero’s are PLACEHOLDERS

Ex:  180,000  =  “around” 180,000 

TWO SIGNIFICANT FIGURES

 

180,000.  = SIX significant figures (if there IS a decimal point present)

This is 1.80000 x 105

 

Placeholder zero’s can be insignificant

 

0.0010 has two significant numbers   0.0010 =   1.0 x 10-3 

 

50.    =  5.0 x 101

500. = 5.00 x 102

50 = 5.0 x 101

 

 

DIMENSIONAL ANALYSIS:

 

How many meters are in 77 inches?

 

?m = 77 in

 

77 in     |  2.54 cm      |      1 x 10–2 m   |    =  77 x 2.54 * 10-2  =  195.58 x 10-2  or 1.96 

            |  1 inch         |       1 cm           |

 

 

 

Part / Whole x 100 = percent

 

10g NaCl + 100g H2) –

What percent salt solution is that?   (what’s the percentage of NaCl?)

10g is the part,  110g is the whole

10/110 = .09 or 9.09%  (9.1%)

 

Part/Whole  x 106 = PPM or parts per million

 

PRIMARY AIR POLLUTANTS:

CO      CO2     SO2      NO      NO2   

Most hydrocarbons

Most particulates

 

 

SECONDARY AIR POLLUTANTS:

(combine with things in the air)

 

HNO2              HNO3              SO3                  H2SO4             H2O2    O3        PANs

 

Since 1970, CO has decreased, VOC’s have decreased, SO2 has decreased, Lead has decreased and Particulates have decreased, but: not much progress with NOx.

 

Smog: 2 kinds –

photochemical (Los Angeles, for ex.) 

“London” – coal-burning (SO2 particulates)

 

Inversion:   Warm air trapped by cold air at the top & underneath

 

 

Risk-benefit analysis:  probability of problem x severity of problem x ##population affected

            Example: milk – “drink it, it’s good for you” (vs lactose allergies)

 

Benefit/risk ratio:  “DQ” = desirability quotient

 

Milk: Large benefit / small risk – large DQ

 

Thalidomide:  Small benefit/large risk  SMALL DQ  (don’t do)

 

 

 

1m  =  109 nm

 

Looking at Dimensional Analysis:

 

If it is a small unit over large unit (as in nano unit over regular-size unit), no negative exponents.

 

            109 nm                        

   1m

 

However, if the smaller of the two unit measurements is on the bottom, then we do use a negative exponent on top.

10-9 m

 1 nm

 

 

Dalton’s Theory: (from Zumdahl’s CHEMISTRY text, 5th edition, p. 45)

1.      All matter consists of tiny particles (atoms, molecules)

2.      The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways. 
(Fundamentally, differences among atoms are their masses.)

3.      Chemical compounds are formed when atoms combine with each other.  A given compound always has the same relative numbers and types of atoms.

4.      Chemical reactions involve reorganization of the atoms – changes in the way they are bound together.  The atoms themselves are not changed in a chemical reaction.

 

Dimensional Analysis again:

1 mol C  1 mol O2    = 1 mol CO2

 


8 g  O2   |         1 mol O2          |           1 mol C      |     12 g C              = 8 x 12 g C

              |         32g O2             |           1 mol O2    |      1 mol C                 32  

                                                                                                                        = 96/32  or  3 g C

 

 

 

 

Allotrope:

            2 or more forms of the same element that differ in their molecular or crystal structure and therefore in their properties

 

Protons & Neutrons have almost exactly the same mass; Electrons have 1/2000th the mass of a proton or neutron (electrons are really, really SMALL)

 

OZONE HOLE – caused by CFC’s

 

OZONE: (O3) – good in stratosphere, NOT good in troposphere

 

 

 

IONS:

METALS ALWAYS FORM POSITIVE IONS

(aka: cations)