Chapter 2

What is Matter?

Chemistry

• Considered a central science because it touches all the other sciences

Submicroscopic World• ATOMS

–Small–Single grain of

sand contains 125 million trillion atoms

• MOLECULES–Linked atoms–8oz glass of

water contains a trillion trillion H2O molecules

Nitrogen

Ato

m

Mole

cule

33%

67%

a) Atom

b) Molecule

Au is gold on the periodic table

Ato

m

Mole

cule

15%

85%a) Atom

b) Molecule

H2O

Ato

m

Mole

cule

100%

0%

a) Atom

b) Molecule

H2O as ice

Ato

m

Mole

cule

95%

5%

a) Atom

b) Molecule

H2O as vapor

Ato

m

Mole

cule

100%

0%

a) Atom

b) Molecule

H2O

a) Atom

b) Molecule whether solid liquid or gas

O2

Ato

m

Mole

cule

89%

11%

a) Atom

b) Molecule

He (Helium)

Ato

m

Mole

cule

5%

95%

a) Atom

b) Molecule

CO2

Ato

m

Mole

cule

95%

5%

a) Atom

b) Molecule

N2

Ato

m

Mole

cule

100%

0%

a) Atom

b) Molecule

N2

a) Atom

b) called a Diatomic Molecule

• ELEMENT–Made of only

one type of atom

Distinction – elements are made of atoms, and not the other way around

• COMPOUNDS–Made of 2 or

more elements–Every

compound’s properties are different than the elements it contains

H2S

Ele

men

t

Com

pound

100%

0%

a) Element

b) Compound

Ne

ele

men

t

com

pound

0%

100%

a) element

b) compound

Po

ele

men

t

com

pound

0%

100%

a) element

b) compound

H2O2

Ele

men

t

Com

pound

100%

0%

a) Element

b) Compound

Chemical formulas• Glucose C6H12O6

• Hydrogen peroxide 2 H2O2

• Methane CH4

• Quartz 3 SiO2

• Shows the ratio of atoms used to make a compound

Number of elements in SiO2

0 1 2 3

0%5%

65%

30%

a) 0

b) 1

c) 2

d) 3

Total Number of atoms in SiO2

0 1 2 3

5%

55%

35%

5%

a) 0

b) 1

c) 2

d) 3

Number of elements in 2 CaF2

Answer = 2: Ca is one and F is the other

Answer = coefficient 2 x one Ca atom 2 + coefficient 2 x 2 atoms of F in F2 + 4

6 atoms

Total Number of atoms in 2 CaF2 two molecules of calcium fluoride

Number of elements in 2 CuCl2

a) 0

b) 1

c) 2

d) 3

e) 6

Total Number of atoms in 2 CuCl2

a) 0

b) 1

c) 2

d) 3

e) 6

Number of molecules in 2 H2O2

0 2 4 6 8

0% 0% 0%0%0%

a) 0

b) 2

c) 4

d) 6

e) 8

Total number of atoms in 2 H2O2

0 2 4 6 8

0% 0% 0%0%0%

a) 0

b) 2

c) 4

d) 6

e) 8

Review from yesterday

2 C3H8O (isopropyl alcohol)

molecu

le ato

m

0%0%

1. molecule

2. atom

How many types of elements in 2 C3H8O (isopropyl alcohol)

1 2 3 6 16 12 24

0% 0% 0% 0%0%0%0%

1. 1

2. 2

3. 3

4. 6

5. 16

6. 12

7. 24

How many types of atoms in 2 C3H8O (isopropyl alcohol)

1 2 3 6 16 12 24

0% 0% 0% 0%0%0%0%

1. 1

2. 2

3. 3

4. 6

5. 16

6. 12

7. 24

How many molecules in 2 C3H8O (isopropyl alcohol)

1 2 3 6 16 12 24

0% 0% 0% 0%0%0%0%

1. 1

2. 2

3. 3

4. 6

5. 16

6. 12

7. 24

How many total atoms in one molecule of

2 C3H8O (isopropyl alcohol)

1 2 3 6 16 12 24

0% 0% 0% 0%0%0%0%

1. 1

2. 2

3. 3

4. 6

5. 16

6. 12

7. 24

total number of atoms in 2 C3H8O (isopropyl alcohol)

1 2 3 6 16 12 24

0% 0% 0% 0%0%0%0%

1. 1

2. 2

3. 3

4. 6

5. 16

6. 12

7. 24

• PURE SUBSTANCE– Fixed

composition– Definite

properties

• Examples– Elements– Compounds

• Note– Cannot be broken

into its components

MIXTURE

– Varying amounts– No definite

properties

a. Examples

– Air– Stainless steel

b. Note

– Can be broken into its components

MIXTURESMixtures can be physically separated – NOT chemically combined

• Heterogeneous– Not evenly distributed– Not uniform

• Homogeneous– Evenly distributed– Same throughout

________________________

Liquid Mixtures– Miscible: dissolved– Immiscible: does not mix well; layered

Muddy water

pure

subst

ance

mix

ture

0%0%

1. pure substance

2. mixture

Salt water

pure

subst

ance

mix

ture

0%0%

1. pure substance

2. mixture

Isopropyl alcohol, C3H8O

pure

subst

ance

mix

ture

0%0%

1. pure substance

2. mixture

conglomerate

pure

subst

ance

mix

ture

0%0%

1. pure substance

2. mixture

Koolaid

Hom

ogeneo

us

Het

erogen

eous

0%0%

1. Homogeneous

2. Heterogeneous

Air

Hom

ogeneo

us

Het

erogen

eous

0%0%

1. Homogeneous

2. Heterogeneous

A pail of sand and water

Hom

ogeneo

us

Het

erogen

eous

0%0%

1. Homogeneous

2. Heterogeneous

Chocolate syrup

Hom

ogeneo

us

Het

erogen

eous

0%0%

1. Homogeneous

2. Heterogeneous

Properties of Matter• PHYSICAL

–Color

–Hardness

–Density–Texture–Phase–Mass–Volume–Conductivity–Magnetism

Properties can change when conditions change, - BUT still the SAME substance

Properties of Matter• CHEMICAL

– Relates to how a substance reacts• Combines• Breaks apart

– Flammability

– Copper reacts with CO2 to form patina

Changes of Matter

• PHYSICAL CHANGE– Affects one or more

physical properties – but not the identity of atoms

– Phase change • Ex. Melting ice

Quartz crushed into sand

Dissolving

Changes of Matter

• CHEMICAL CHANGE– Rearrangement of

atomic bonds– Chemical reaction

occurs– New substance

formed

• Some compounds can be broken down into elements through a chemical change.

• Detection of change:• In odor• In color• Fizz • Heat• Sound

Bending glass Demo

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Burning methane with the bunsen burner

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Distilling wood

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Distilling liquids left after distilling the wood

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Melting ice

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Freezing water

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Melting moth nuggets or flakes

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Freezing moth nuggest and flakes

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Cooking an egg

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change

Painting wood

Phys

ical

cha

nge

Chem

ical

chan

ge

0%0%

1. Physical change

2. Chemical change