Post on 18-Jan-2016
transcript
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