Unit 2:Matter and Energy

HonorsChemistry

Guiding Questions

Why do substances boil or freeze at different temperatures? Why do we put salt on the roads in the winter?

Why does sweating cool us?

What is energy?

How do we measure energy?

                                                

      

units: L, dm3, mL, cm3

Matter Introductory Definitions (…pull out your vocab!)

matter: anything having mass and volume

mass:

weight:

volume:

L3state of matter:

the amount of matter in an object

the pull of gravity on an object

the space an object occupies

solid, liquid, or gas

Solid, Liquid, Gas

(a) Particles in solid (b) Particles in liquid (c) Particles in gas

composition:

copper: water:

properties:

atom: a basic building block of matter

what the matter is made of

many Cu atoms many groups of2 H’s and 1 O

describes matter

what it looks like, smells like, etc.

how it behaves

~100 diff. kinds

Qualitative observations

Lr103

No102

Md101

Fm100

Es99

Cf98

Bk97

Cm96

Am95

Pu94

Np93

U92

Pa91

Th90

Lu71

Tm69

Yb70

Er68

Ho67

Dy66

Tb65

Gd64

Eu63

Sm62

Pm61

Nd60

Pr59

Ce58

He2

Ne10

Ar18

Kr36

Xe54

Rn86

At85

I53

Br35

Cl17

F9

Po84

Te52

Se34

O8

Bi83

Sb51

As33

N7

Pb82

Tc43

Ta73

Hg80

Mt109

Hs108

Bh107

Sg106

Db105

Rf104

Ac89

La57

Hf72

W74

Re75

Os76

Ir77

Rh45

Ru44

Mo42

Nb41

V23

Li3

Fr87

Cs55

H 1

Na11

K19

Rb37

Mn25

Co27

Pd46

Au79

Cd48

Zn30

Cu29

C6

B5

Al13

S16

P15

Si14

Ge32

Sn50

Ag47

Pt78

= Internet link( )

Fe26

Ni28

Cr24

Ti22

Sc21

Zr41

Y39

Ga31

In49

Tl81

Mg12

Ca20

Sr38

Ba56

Ra88

Be4

Select an element

Other Physical DATA

The Periodic Table of Elements

Rg111

Ds110

Cp112

Uut113

Fl114

Uup115

Lv116

Uus117

Uuo118

Elements contain only one type of atom

1. monatomic elements consist of unbonded, “like” atoms

e.g.,

2. polyatomic elements consist of several “like” atoms bonded together

diatomic elements:

Fe, Al, Cu, He

H2 O2 Br2 F2 I2 N2 Cl2

“HOBrFINCl = Hoberfinckle” “BrINClHOF = Brinklehoff”

others: P4 or S8

Diatomic Elements, 1 and 7H2

N2 O2 F2

Cl2

Br2

I2

allotropes: different forms of the same element inthe same state of matter

OXYGEN CARBON

oxygen gas

ozone

elementalcarbon graphite

diamond buckyball

(O2)

(O3)

Allotropes of Carbon

Graphite

Diamonds

Allotropes of Carbon

C60 & C70

“Buckyballs”“Buckytubes”

BuckminsterfullereneBuckminster Fuller was known for designing geodesic domes, like Epcot Center

Allotropes of Carbon

Carbon nanotubes

Allotropes of Carbon

GrapheneSuper strong and super conductive

molecule: a neutral group of bonded atoms

Description Chemical Symbol Model

1 oxygen atom

1 oxygen molecule

2 unbonded oxygen atoms

1 phosphorus atom

1 phosphorus molecule

4 unbonded phosphorus

atoms

O

O2

2 O

P

P4

Elements may consist of either molecules or unbonded atoms

4 P

Compounds

…contain two or more different types of atoms…have properties that are different from those of their constituent elements

Na (sodium):

Cl2 (chlorine):

explodes in water

poisonous gas

table salt (NaCl)

Atoms can be altered onlyby _______ means

Molecules can be alteredby ________ means

(i.e., chemical reactions)

nuclear

chemical

e.g., Dehydration of sugar

C12H22O11(s) 12 C(s) + 11 H2O(g)

Electrolysis of water

2 H2O(l) 2 H2(g) + O2(g)

Atomic blast at Hiroshima

U

BaKr

neutron“bullet”

Classifying Matter

(Pure) Substances …have a fixed composition

…have fixed properties

ELEMENTS COMPOUNDS

e.g., e.g., Fe, N2, S8, U H2O, NaCl, HNO3

Pure substances have a chemical formula

sulfur (S8) sodium chloride (NaCl)

Mixtures two or more substances mixed together

…have varying composition

…have varying properties

The substances are NOT chemically bonded,and they… retain their individual properties

Tea, orangejuice, oceans,and air are all

mixtures

Two Types of Mixtures

1. homogeneous: (or solution) particles are microscopic; sample has the samecomposition and properties throughout;evenly mixed

e.g.,

alloy: a homogeneous mixture of metals

e.g.,

Kool Aid

bronze (Cu + Sn) brass (Cu + Zn) pewter (Pb + Sn)

salt water

Oh Yeah!

Two Types of Mixtures (cont.)2. heterogeneous:

different composition and properties in thesame sample; unevenly mixed

e.g.,

suspension: settles over time

e.g.,

tossed salad

raisin bran

paint snowy-bulb gifts

MATTER

Chart for Classifying Matter

PURE SUBSTANCE MIXTURE

ELEMENT COMPOUND

HOMOGENEOUS

HETEROGENEOUS

Has a chemical formula Has NO chemical formula

Made of 1 element Made of 2 or more different elements

Unevenly mixed

Uniform or evenly mixed throughout (a solution)

Alike DifferentDifferent

Topic Topic

Double Bubble Mind Map

Mixture vs. Compound

Mixture

FixedComposition

Bonds between

components

Can ONLY beseparated by

chemical means

VariableComposition

No bondsbetween

components

Can beseparated by

physical means

Alike Different

Contain two or more

elements

Can beseparated

intoelements

Involvesubstances

Compound

Different

Topic Topic

Contrast…

24K GOLD 14K GOLD

24/24 atoms are gold

element

pure gold

14/24 atoms are goldmixture of gold & other metals

Auhomogeneous mixturee.g., Au + Cu

Every sample of NaCl tastes the same, melts at the same temp., and is 39.3% Na and 60.7% Cl

by mass.

Compound Composition

All samples of a given compoundAlways have the same composition

Phosgene gas (COCl2) is 12.1% carbon,16.2% oxygen, and 71.7% chlorine bymass. Find # of g of each element in254 g of COCl2.

C:

O:

Cl:

254 g (0.121) = 30.7 g C

254 g (0.162) = 41.1 g O

254 g (0.717) = 182 g Cl

= 0.828

A sample of butane (C4H10) contains 288 g carbonand 60. g hydrogen. Find…

A. …total mass of sample

B. …% of each element in butane

C. …how many g of C and H are in a 24.2 g sample

288 g C + 60 g H

82.8% C17 % H

= 348 g

g 348

C g 288% C =

= 0.17g 348

H g 60.% H =

C:

H:

24.2 g (0.828) = 20.0 g C

24.2 g (0.17) = 4.2 g H 24.2 g

A 550 g sample of chromium (III) oxide (Cr2O3)has 376 g Cr. How many grams of Cr and Oare in a 212 g sample of Cr2O3?

68.4% Crg 550Cr g 376

% Cr =and

31.6% O

Cr:

O:

212 g (0.684) = 145 g Cr

212 g (0.316) = 67 g O

chromium (III) oxide

100 %

A sample of bronze contains 68 g copper and 7 g tin

A. Find total mass of sample

B. Find % Cu and % Sn

C. How many grams of each element does a 346 g sample of bronze contain?

68 g Cu + 7 g Sn = 75 g

90.7% Cug 75Cu g 68

% Cu = and 9.3% Sn

We don’t know! (Bronze is a mixture and isn’t necessarily

always 90.7% Cu and 9.3% Sn.)

However, assuming these % are correct…

Cu: 346 g (0.907) = 314 g Cu (and 32 g Sn)

Separating Mixtures …involves physical means, or physical changes

1. sorting:

2. filter:

by color,shape,texture,etc.

particle sizeis different

filtration in the chemistry laboratory

filtration in the “real world”

Separating Mixtures (cont.)

3. magnet:

4. chromatography:

one substance mustcontain iron

some substances dissolvemore easily than others

Separating Mixtures (cont.)

5. density: “sink vs. float”

perhaps use a centrifuge

decant: to pouroff the liquid

blood after high-speed centrifuging

Separating Mixtures (cont.) 6. distillation: different boiling points

heat source

thermometer

water in(cooler)

water out(warmer)

more-volatile substance

mixture

condenser

more-volatilesubstance, nowcondensed

(i.e., the onewith the lowerboiling point)

No chemical reactionsare needed to separate mixtures;

substances are NOT bonded

dental amalgam

Density how tightly packed the particles are

Density =

Typical units:

g/cm3 for solids g/mL for fluids

Vm D

volumemass m

V D

liquids and gases

Glass: liquid or solid?

To find volume, use…

1. a formula

water displacement

V = l ∙ w ∙ hV = p ∙ r2 ∙ h

V = ?

VfinalVinitial

Vobject = Vfinal – Vinitial

2.

** Density of water =

The density of a liquid or solid is nearly constant,no matter what the sample’s temperature

1.0 g/mL = 1.0 g/cm3

Things that are “less dense” floatin things that are “more dense.”

D < 1 g/cm3

Density of gases is highly dependent on temperature

D < 1 g/cm3D > 1 g/cm3D < 1 g/cm3

(And things that are “more dense” sinkin things that are “less dense.”

Ironwood Trees

• Several different varieties of hardwood trees, having densities between 1.34 and 1.49 g/cm3

• Most dense species is South African Ironwood (black ironwood)• Olea laurifolia• Found in Florida and

West Indies• D = 1.49 g/cm3

Will Bowling Balls sink or float in H2O?

21.6 cm in diameterVsphere = 4/3 p r3

V = 4/3 p (10.8 cm)3

V = 5,276.7 cm3

If DBB > 1, it will sink If DBB < 1, it will float

Since the mass of a BB varies, let’s figure out at what mass it will sink v. float

m = (1.00 g/cm3)(5276.7 cm3)

m

V D

m = 5276.7 g

m = D V

…or 11.6 lbs

Density Calculations

1. A sample of lead (Pb) has mass 22.7 g and volume 2.0 cm3. Find sample’s density.

Vm

D 3cm 2.0g 22.7

m

V D

2. Another sample of lead occupies 16.2 cm3

of space. Find sample’s mass.

33 cm 16.2

cmg

11.35 m = D V = 180

3cmg

= 11

g

V

3cmg

3. A 119.5 g solid cylinder has radius 1.8 cm and height 1.5 cm. Find sample’s density.

1.5 cm

1.8 cm

m

V D

m

V = p r2 h

Vm

D

= p (1.8 cm)2(1.5 cm)

= 15.268

3cm 15.268

g 119.5 = 7.8

cm3

4. A 153 g rectangular solid has edge lengths 8.2 cm, 5.1 cm, and 4.7 cm. Will this object sink in water?

8.2 cm

5.1 cm

4.7 cm

m

V D

Vm

D

(Find the object’s density and compare it to water’s density.)

m

V = l w h

= 8.2 cm (5.1 cm)(4.7 cm)

3cmg

= 196.55

3cm 196.55

g 153 = 0.78

cm3

< 1 No; it floats.

Galilean Thermometer ProblemOn a cold morning, a teacher walks into acold classroom and notices that all bulbsin the Galilean thermometer are huddledin a group. Where are the bulbs? At thetop of the thermometer, at the bottom or elsewhere?

1. Bulbs have essentially fixed masses

and volumes. Therefore, each bulb has a relatively fixed density. 2. The surrounding liquid has a fixed

mass, but its volume is extremely

temperature-dependent.

D1

D2

D3

D4

D5

D1

D2

D3

D4

D5

3. The density of the liquid can be written as…

liq

liqliq V

m D so…

…if the liquid is cold: …but if it’s hot:

mliq =

On a cold morning,where are the bulbs? AT THE TOP

Vliq

mliq Dliq=

VliqDliq

•  

Osmium

Properties of Matter

CHEMICAL properties tell how a substance reacts with other substances

PHYSICAL properties can be observed without chemically changing the substance

EXTENSIVE properties depend on the amount of substance present

INTENSIVE properties do not depend on the amount of substance

ON

E O

F T

HE

SE

AND

ON

E O

F T

HE

SE

P,

Examples:

electrical conductivity……………………..…

reactivity with water……………………….....

heat content (total energy)………………..…

ductile: can be drawn (pulled) into wire…..

malleable: can be hammered into shape…

brittle…………………………………………….

magnetism………………………………………

C,

P,

I

I

E

P, I

P, I

P, I

P, I

Physical and Chemical PropertiesExamples of Physical Properties

Boiling point Color Slipperiness Electrical conductivity

Melting point Taste Odor Dissolves in water

Shininess (luster) Softness Ductility Viscosity (resistance to flow)

Volatility Hardness Malleability Density (mass / volume ratio)

Examples of Chemical Properties

Burns in air Reacts with certain acids Decomposes when heated

Explodes Reacts with certain metals Reacts with certain nonmetals

Tarnishes Reacts with water Is toxic

Ralph A. Burns, Fundamentals of Chemistry 1999, page 23Chemical properties can ONLY be observed during a chemical reaction!

The formation of a mixture

The formation of a mixture

The formation of a compound

The formation of a compoundChemical Change

Chemical Change

Physical Change

Physical Change

Physical & Chemical Changes

Limestone,CaCO3

crushing

PHYSICALCHANGE

Crushed limestone,CaCO3

heating

CHEMICALCHANGE

Pyrex

CO2

CaO

Lime andcarbon dioxide,

CaO + CO2

Pyrex

O2

H2O

Pyrex

H2O2

Light hastens the decomposition of hydrogen peroxide, H2O2. The dark bottle in which hydrogen peroxide is usually storedkeeps out the light, thus protecting the H2O2 from decomposition.

Sunlight energy

States of MatterLIQUID SOLID GAS

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

( ( ) )

vibrating translating;close together

translating quickly;far apart

Changes in State Energy put into system

Energy removed from system

LIQUID GASSOLID

freezing condensation

deposition

sublimation

boilingmelting

Energy the ability to do work

potential energy:

kinetic energy:

--

--

e.g.,

stored energy

stored in bonds between atoms

in food,

energy of motion

wiggling, translating,and rotating of particles

-- “hot” gas particles movefaster, have more KE

gasoline, batteries

Law of Conservation of Energy:

2 H2 + O2 2 H2O

Eafter = Ebefore

+

+ energy

+WHOOF!

For the combustion of acetylene…

PEreactants

PEproducts

KEstopper

heat, light, sound

EN

ER

GY

CO2 + H2OC2H2 + O2

Energy is conserved.

Energy Changes

endothermic change: system absorbs heat

exothermic change: system releases heat --

--

Choose “endo” or “exo”…

water boiling

paper burning

steam condensing

CO2 subliming

water freezing

ice melting

beaker feels cold

beaker feels hot

ENDO

EXO

EXO

ENDO

EXO

ENDO

R

P

En

erg

y endothermic exothermic

R

P

En

erg

yACTIVATION

ENERGY

(most chemical reactions) (photosynthesis)

CO2 + H2O + sunlight C6H12O6 + O2

C + O2 CO2

Reaction Coordinate Diagrams

The Mole

Atoms are so small, it is impossible to count them bythe dozens, thousands, or even millions.

To count atoms, we use the concept of the mole

1 mole of atoms =

That is, 1 mole of atoms = _________ atoms

The mole is the SI unitfor “amount of substance.”

602,000,000,000,000,000,000,000 atoms

6.02 x 1023

How Big is a Mole?

…about the size of a chipmunk,weighing about 5 oz. (140 g), andhaving a length of about 7 inches (18 cm).

I Meant, “How Big is 6.02 x 1023?” BIG.6.02 x 1023 marbles would cover theentire Earth (including the oceans)

…to a height of 2 miles.

6.02 x 1023 $1 bills stacked face-to-face

…and back …7.5 million times.

(It takes light 9,500 years to travel that far)

would stretch from the Sun to Pluto

For any element on the Periodic Table,one mole of that element

(i.e., 6.02 x 1023 atoms of that element)has a mass in grams equal to the decimal

number on the Table for that element.

He2

4.003

Ne10

20.180

Ar18

39.948

Kr36

83.80

Xe54

131.29

Rn86

(222)

1 mole of (i.e., 6.02 x 1023) helium atomshas a mass of 4.0 grams.

1 mol Ne = 20.2 g1 mol Ar = 39.9 g1 mol Kr = 83.8 g

1 mol Xe = 131.3 g

1 mol Rn = 222 g

1 mol = 6.02 x 1023 particles

MOLE(mol)

MASS(g)

Particle(atoms)

1 mol = molar mass (in g)

Island Diagram

Island Diagram Problems

1. How many moles is 3.79 x 1025 atoms of zinc?

= 63.0 mol Zn( )1 mol6.02 x 1023 at.

3.79 x 1025 at.

2. How many atoms is 0.68 moles of zinc?

= 4.1 x 1023 at. Zn( )1 mol6.02 x 1023 at.

0.68 mol.

3. How many grams is 5.69 moles of uranium?

5.69 mol( )1 mol238.0 g

= 1,354 g U= 1.35 x 103 g U

4. How many grams is 2.65 x 1023 atoms of neon?

( )1 mol

= 8.9 g Ne

20.2 g( )1 mol6.02 x 1023 at.

2.65 x 1023 at.

5. How many atoms is 421 g of promethium?

421 g( )1 mol145 g ( )1 mol

6.02 x 1023 at.

= 1.75 x 1024 at. Pm