Transcript General Chemistry CHEM 103

Chapter 1
Matter
and
Measurement
Dr. S. M. Condren
Chemistry
• What is it?
• Why do we study it?
Dr. S. M. Condren
Development of Periodic Table
Dmitri Mendeleev - Russian
1869 - Periodic Law - allowed him to
predict properties of
unknown elements
- the elements are
arranged according to
increasing atomic
weights
Dr. S. M. Condren
Periodic
Table
of the
Periodic
Table
of the
Elements
Elements
IA
1
1
2
3
4
5
6
7
II A
III B
IV B
VB
VI B
VII B
VIII B
IB
II B
III A
IV A
VA
VI A
VII A
1
VIII A
2
H
H
He
1.008
1.008
3
4
5
6
7
8
9
4.0026
10
Li
Be
B
C
N
O
F
Ne
6.939
9.0122
10.811
12.011
14.007
15.999
18.998
20.183
11
12
13
14
15
16
17
18
Na
Mg
Al
Si
P
S
Cl
Ar
22.99
24.312
26.982
28.086
30.974
32.064
35.453
39.948
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
39.102
40.08
44.956
47.89
50.942
51.996
54.938
55.847
58.932
58.71
63.54
65.37
69.72
72.59
74.922
78.96
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
79.909
53
83.8
54
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
85.468
87.62
88.906
91.224
92.906
95.94
* 98
101.07
102.91
106.42
107.9
112.41
114.82
118.71
121.75
127.61
126.9
131.29
55
56
57
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
Cs
Ba
**La
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
132.91
137.33
138.91
178.49
180.95
183.85
186.21
190.2
192.22
195.08
196.97
200.29
204.38
207.2
208.98
* 209
* 210
* 222
87
88
89
104
105
106
107
108
109
110
111
112
113
114
115
116
Rf
Ha
Sg
Ns
Hs
Mt
* 261
* 262
* 263
* 262
* 265
* 268
Fr
* 223
Ra ***Ac
226.03 227.03
58
* Designates that **Lanthanum
all isotopes are
Series
radioactive
*** Actinium
Series
59
60
61
62
Uun Uuu Uub
* 269
* 272
63
64
* 277
65
Uut
118
Uuq Uup Uuh
Uuo
*284
*285
*288
*292
Based on symbols used by ACS
66
67
68
69
S.M.Condren 2006
*294
70
71
Ce
Pr
Nd
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
140.12
140.91
144.24
* 145
150.36
151.96
157.25
158.93
162.51
164.93
167.26
168.93
173.04
174.97
90
91
92
93
94
95
96
97
98
99
100
101
102
103
Th
Pa
U
Np
Pu
Am
Cm
Bk
Cf
Es
Fm
Md
No
Lr
232.04
231.04
238.03
237.05
* 244
* 243
* 247
* 247
* 251
* 252
* 257
* 258
* 259
* 260
Dr. S. M. Condren
Dr. S. M. Condren
http://mrsec.wisc.edu/Edetc/LEGO/LEGO PT final.html
Dr. S. M. Condren
Glenn T. Seaborg
Winner of the 1951 Nobel Prize in
Chemistry
Dr. S. M. Condren
Physical States
• solid
– fixed volume and shape
• liquid
– fixed volume
– shape of container, horizontal top surface
• gas
– takes shape and volume of container
• liquid crystal
– some characteristics of solid and some of liquid
states
Dr. S. M. Condren
Liquid Crystals
Dr. S. M. Condren
Amorphous Metal
• Atoms in the steel move past each other in the bouncing of the
bearing, absorbing some of the energy of the bearing
• Amorphous metal is so tightly packed that this does not occur
because the atoms of different sizes and randomly pack
http://mrsec.wisc.edu/Edetc/SlideShow/slides/amorphous/glass.html
Dr. S. M. Condren
Properties of Matter
Extensive Property
• depends on specific
sample under
investigation
• examples:
– mass and volume
Intensive Property
• identical in all
samples of the
substance
• examples:
– color, density, melting
point, etc.
Dr. S. M. Condren
Density
• Mass per unit of volume
d = m/V
• Mass equals volume times density
m = d*V
• Volume equals mass divided by density
V = m/d
Dr. S. M. Condren
Physical Property
• one that can be observed without
changing the substances present in the
sample
• changes in physical properties of
substances
Dr. S. M. Condren
Chemical Property
• the tendency to react and form new
substances
Dr. S. M. Condren
Chemical Reaction
• reactants undergo chemical change to
produce products
sucrose ---> carbon + water
reactant
products
Dr. S. M. Condren
Chemical Reaction
Reactions are indicated by:
• evolution of a gas
• change of color
• formation of a precipitate
Dr. S. M. Condren
Pure Substances
Elements
Compounds
Dr. S. M. Condren
Atoms-Molecules-Ions
• Atoms – smallest subdivision of an
element that retains all of the properties of
the element
• Molecules – two or more atoms linked
(bonded) together
• Ions – charged atoms or groups of atoms
Dr. S. M. Condren
Mixtures
Heterogeneous
• uneven texture
Homogeneous (Solution)
• sample uniform throughout
Dr. S. M. Condren
Matter
• What is matter?
Anything that has mass and occupies space
Dr. S. M. Condren
Separation of Matter
Dr. S. M. Condren
Fractional Distillation
Dr. S. M. Condren
Soxhlet Extractor
Dr. S. M. Condren
Important Metric Unit Prefixes
deci -- 1/10*
centi -- 1/100*
milli -- 1/1000*
nano -- 1/1,000,000,000
kilo -- 1000*
Dr. S. M. Condren
Significant Figures
Rules for determining which digits are
significant:
• All non-zero numbers are significant
• Zeros between non-zero numbers are
significant
• Zeros to the right of the non-zero number and
to the right of the decimal point are significant
• Zeros before non-zero numbers are not
significant
Dr. S. M. Condren
Significant Figures Examples:
Regular Lab Balance
• 1,000 g + 0.1 g
1.0000 x 103 g
5 sig. fig.
• 400 g + 0.01 g
4.0000 x 102 g
5 sig. fig.
• 100 + 0.001 g
1.00000 x 102 g
6 sig.fig.
Dr. S. M. Condren
Rules for Mathematics
Multiplication and Division
For multiplication and division, the number of significant
figures used in the answer is the number in the value
with the fewest significant figures.
(2075)*(14)
---------------- = 2.0 x 102
(144)
4 sig. fig.; 2 sig.fig.; 3 sig. fig. => 2 sig. fig.
Dr. S. M. Condren
Rules for Mathematics
Addition and Subtraction
For addition and subtraction, the number of
significant figures used in the answer is
determined by the piece of data with the
fewest number decimal places.
4.371
302.5
-------306.8
Dr. S. M. Condren
Rules for Mathematics
Addition and Subtraction
For addition and subtraction, the number of
significant figures used in the answer is
determined by the piece of data with the
fewest number decimal places.
4.371
302.5
-------306.8
Dr. S. M. Condren
Rules for Mathematics
Addition and Subtraction
For addition and subtraction, the number of significant
figures used in the answer is determined by the piece of
data with the fewest number decimal places.
4.371 (I truncate extra data)
302.5
-------306.8
Dr. S. M. Condren
Exact Numbers
• conversion factors
• should never limit the number of significant
figures reported in answer
12 inches = 1 foot
Dr. S. M. Condren
Round Off
• Chemistry is an inexact science
• all physical measurements have some
error
• thus, there is some inexactness in the last
digit of any number
• use what ever round-off procedure you
choose
• reasonably close answers accepted
Dr. S. M. Condren
Heat vs. Temperature
• heat – a form of energy
• temperature
– one way of measuring heat
– determines the direction of flow of heat
Dr. S. M. Condren
Comparison of Temperature
Scales
Fahrenheit
Celcius
98.6
37.0
comfort temp. 68.0
20.0
bp water
212
100
mp
32
0
bp-mp
180
100
body temp.
Dr. S. M. Condren
Temperature Relationships
oC
= 100/180 * (oF - 32)
oF
= (180/100)*oC + 32
K = oC + 273.15
- 40o F = - 40o C
Dr. S. M. Condren
If the temperature of the room goes from 20
degrees C to 40 degrees C, the ambient
thermal energy
– doubles
– is halved
– increases by less than 10%
Dr. S. M. Condren
Problem Solving by
Dimensional Analysis
• state question in mathematical form
• set equal to piece of data specific to the
problem
• use conversion factors to convert units of
data specific to problem to units sought in
answer
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
state question in mathematical form
#km
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
set equal to piece of data specific to the
problem
#km = 0.200 miles
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
use conversion factors to convert units of
data specific to problem to units sought in
answer
#km = (0.200 miles)
* (5280 ft/mile)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
cancel units
#km = (0.200 miles)
* (5280 ft/mile)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
add another conversion factor
#km = (0.200)*(5280 ft)
*(12 in/ft)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
cancel units
#km = (0.200)*(5280 ft)
*(12 in/ft)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
#km = (0.200)*(5280)*(12 in)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
add still another conversion factor
#km = (0.200)*(5280)*(12 in)
*(2.54 cm/in)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
cancel units
#km = (0.200)*(5280)*(12 in)
*(2.54 cm/in)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
#km = (0.200)*(5280)*(12)*(2.54 cm)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
add still another conversion factor
#km = (0.200)*(5280)*(12)*(2.54 cm)
*(1 m/100 cm)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
cancel units
#km = (0.200)*(5280)*(12)*(2.54 cm)
*(1 m/100 cm)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
#km = (0.200)*(5280)*(12)*(2.54)
*(1 m/100)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
add still another conversion factor
#km = (0.200)*(5280)*(12)*(2.54)
*(1 m/100)*(1 km/1000 m)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
cancel units
#km = (0.200)*(5280)*(12)*(2.54)
*(1 m/100)*(1 km/1000 m)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
#km = (0.200)*(5280)*(12)*(2.54)
*(1/100)*(1 km/1000)
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
solve mathematics
#km = (0.200)*(5280)*(12)*(2.54)
*(1/100)*(1 km/1000)
= 0.322 km
3 sig. fig.
Dr. S. M. Condren
Example
How many kilometers are there in 0.200
miles?
solve mathematics
#km = (0.200)*(5280)*(12)*(2.54)
*(1/100)*(1 km/1000)
= 0.322 km
3 sig. fig.
exact numbers
Dr. S. M. Condren