Pure Substance: Matter that is constant in its chemical composition and properties.
Mixture: A blend of two or more pure substances in any ratio each retaining their identity.
Physical changes can separate mixtures into one or more pure substances.
Matter
Pure Substance
Mixture
Are properties andcomposition constant?
YESNO
Physical change
Matter
Pure Substance
Mixture
Chemical Compound
Element
Are properties andcomposition constant?
YESNO
Physical change
Is separation by chemical reaction into simpler substances possible?
NO YES
Chemical change
ElementElements are substances that cannot be broken
down chemically into simpler substances.
All of the atoms that make up a particular element are chemically the same as all of the others
All of the atoms that make up a particular element contain the same number of protons as all other atoms of that element.
Pure SubstancesChemical Compounds: Two or more elements combined chemically in specific ratios to form a pure substance.
Water = H2O
Methanol = CH3OH
Nitroglycerine = C3H5(NO3)3
Matter
Pure Substance
Mixture
Chemical Compound
ElementHeterogeneous
Mixture Homogeneous
Mixture
Are properties andcomposition constant?
YESNO
Physical change
Is separation by chemical reaction into simpler substances possible?
NO YES
Are properties consistant from sample to sample?
NO YES
Chemical change
MixturesHeterogeneous Mixture: A mixture of matter in whichthe properties change from sample to sample.Hetero
change
Sand and sugar
Quartz and gold
Matter
Pure Substance
Mixture
Chemical Compound
ElementHeterogeneous
Mixture Homogeneous
Mixture
Are properties andcomposition constant?
YESNO
Physical change
Is separation by chemical reaction into simpler substances possible?
NO YES
Are properties consistant from sample to sample?
NO YES
Chemical change
Mixtures
Homogeneous Mixture: A mixture of matter in whichthe properties remain constant from sample to sample.Homo
constant
Salt water
Kool-AidBrass
Classification of MatterLabel each of the following as either: element, compound, homogenous mixture or heterogeneous mixture
Carbon dioxide
Tea brewed from tea bags
Water, distilled and deionized
Oxygen gas
An egg
Apple Juice
compound
homogenous mixture
compound
element
heterogeneous mixture
homogenous mixture
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
1) Law of Conservation of Mass
Total mass must be same before and after a reaction
2) Law of Definite Proportions
No matter the source, a compound is always made of the same elements in the same mass ratio
3) Law of Multiple Proportions
If two elements combine to form more than one type of compound with each other, the masses of one element that combined with a fixed mass of the other element are in ratios of small whole numbers
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
1) Law of Conservation of Mass
Total mass must be same before and after a reactionI am BBQing and start with 20 pounds of charcoal. When I am done, there is only 4 pounds of ash left. How can we explain the apparent failure of the Law of Mass Conservation?
48.0 g of carbon react with 128 g of oxygen, how much CO2 should be formed?
176 g CO2(g)
48.0 g of carbon react with 148 g of oxygen. After the reaction is complete, there is still only 176 g of CO2 formed. Has the Law of Conservation of Mass failed?
20.0 g O2(g) left over
48.0 g of carbon react with 128 g of oxygen, forming 176 g CO2, how much CO2 should be formed from 72.0 g of carbon?48.0 g of carbon react with 128 g of oxygen, forming 176 g CO2, how much CO2 should be formed from 72.0 g of carbon?
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
2) Law of Definite Proportions
No matter the source, a compound is always made of the same elements in the same mass ratio
X = 264 g CO2(g)
2 2
48.0 g C
g CO17
7=
2
6 g
.0
C
C
O
g
X 227
482.0
.0 g
176
C=g g CO
CO C
g X
48.0 g of carbon react with 128 g of oxygen, forming 176 g CO2, how much O2 should be react with 72.0 g of carbon?
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
2) Law of Definite Proportions
No matter the source, a compound is always made of the same elements in the same mass ratio
48.0 g of carbon react with 128 g of oxygen, forming 176 g CO2, how much O2 should be react with 72.0 g of carbon?
X = 192 g O2(g)
2 2
48.0 g C
g 12
7
8
2
g
.
O=
C
O
0 g
X 227
482.0
.0 g
128
C=g
g C O
O g X
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
2) Law of Definite Proportions
No matter the source, a compound is always made of the same elements in the same mass ratio
A 219.6 kg sample of NaCl from The Great Salt Lake contains 86.4 kg of sodium, what mass of chloride would be present in a 76.8 kg sample of NaCl from the Dead Sea?
X = 46.8 kg Cl
219.6 kg Na
g 133.2 kg
76.8
Cl
kg=
NaCll
l
C
CX 133.2 kg C
219.6 k76.8 kg
g NaCl=
l NaC Cll g X
219.6 kg NaCl – 86.4 kg Na = 133.2 kg Cl
A 219.6 kg sample of NaCl from The Great Salt Lake contains 86.4 kg of sodium, what mass of chloride would be present in a 76.8 kg sample of NaCl from the Dead Sea?
219.6 kg NaCl – 86.4 kg Na = 133.2 kg Cl
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
3) Law of Multiple Proportions
If two elements combine to form more than one type of compound with each other, the masses of one element that combined with a fixed mass of the other element are in ratios of small whole numbers
16.0 g of oxygen react with 2.0 g of hydrogen
64.0 g of oxygen react with 4.0 g of hydrogen
416.0 g of oxygen + 1.0 g of hydrogen
16.0 g of oxygen + 2.0 g of hydrogen
64.0 g O4.0 g H
16.0 g O2.0 g H
264.0 g O4.0 g H
16.0 g O2.0 g H
Before There Were Atoms…Three laws that lead to the atomic view of the atom:
3) Law of Multiple Proportions
If two elements combine to form more than one type of compound with each other, the masses of one element that combined with a fixed mass of the other element are in ratios of small whole numbers
89.4 g of oxygen react with 33.6 g of carbon
50.5 g of oxygen react with 37.9 g of carbon
89.4 g O33.6 g C
50.5 g O37.9 g C
289.4 g O33.6 g C
50.5 g O37.9 g C
The Atom
REALLY early atomic theory…Democritus ~350 BCAtomos - Greek meaning indivisible
Modern Definition: Smallest piece that matter can be broken up
into and still maintain the properties of an element
My Atom Broke
Subatomic ParticlesNucleus
Protons – p+
Carry a single positive chargeNumber of p+ = ATOMIC NUMBER1.673x10-24 g
1H
1.013
Li6.9411
Na22.99
19K
39.1037
Rb85.47
55Cs
132.9187Fr
(223)
4Be9.0112
Mg24.31
20Ca40.08
38Sr
87.6256Ba
137.3388
Ra(226)
21Sc
44.9639Y
88.9157La
138.9189Ac(227)
22Ti
47.8840Zr
91.2272Hf
178.49104Rf
(261)
23V
50.9441
Nb92.91
73Ta
180.95
24Cr52.00
42Mo95.94
74W
183.85
25Mn54.94
43Tc(99)75Re
186.21
26Fe
55.8544
Ru101.07
76Os190.2
27Co58.93
45Rh
102.9177Ir
192.22
28Ni
58.6946Pd
106.4278Pt
195.08
29Cu63.55
47Ag
107.8779
Au196.97
30Zn65.39
48Cd
112.4180
Hg200.59
5B
10.8113Al
26.9831
Ga69.72
49In
114.8281Tl
204.38
6C
12.0114Si
28.0932
Ge72.61
50Sn
118.7182Pb207.2
7N
14.0115P
30.9733As
74.9251Sb
121.7583Bi
208.98
8O
16.0016S
32.0734Se
78.9652Te
127.6084Po(209)
9F
19.0017Cl
35.4535Br
79.9053I
126.90
10Ne20.18
18Ar39.95
36Kr83.80
54Xe
131.29
2He4.00
58Ce
140.12
59Pr
140.91
60Nd
144.24
61Pm(147)
62Sm
150.36
63Eu
151.97
64Gd
157.25
65Tb
158.93
66Dy
162.50
67Ho
164.93
68Er
167.26
69Tm168.93
70Yb
173.04
71Lu
174.97
85At
(210)
86Rn(222)
90Th(232)
91Pa(231)
92U
(238)
93Np(237)
94Pu(244)
95Am(243)
96Cm(247)
97Bk(247)
98Cf
(251)
99Es
(252)
100Fm(257)
101Md(258)
102No(259)
103Lr(260)
105Db(262)
106Sg
(263)
107Bh(262)
108Hs(265)
109Mt(266)
110Ds(271)
111Rg(272)
112--
(277)
114--
(285)
116--
(289)
1IA
2IIA
3IIIB
4IVB
5VB
6VIB
7VIIB
8VIII
9VIII
10VIII
11IB
12IIB
13IIIA
14IVA
15VA
16VIA
17VIIA
18VIIIA
My Atom BrokeSubatomic Particles
NucleusNeutrons – no
No charge# can vary from atom to atom
1.675x10-24 g (roughly the same mass as p+)
My Atom Broke
Subatomic ParticlesOutside the nucleus
Electrons – e-
Carry a single negative charge~1830 e- = mass of p+ or no
9.11x10-28gResponsible for most of the chemistry that
ever happens
Atoms vs. IonsAtoms are NEUTRAL!!!!!
This means that they have zero charge#p+ = #e-
Charge!!!
1 p+
1 e – –0
47 p+
47 e– +0
When #p+ = #e-, the atom has no charge and is neutral
Atoms vs. IonsAtoms can gain or lose e- to form IONS
ANY charged particle is called an ionLosing e- gives POSITIVELY charge
