Unit 1
Introduction to Chemistry
Internet web site:
http://old.unit5.org/roller/
Material Safety Data Sheet
(MSDS)
-- gives information
about a chemical
-- lists “Dos” and “Don’ts;”
emergency procedures
Chemical Exposure
acute exposure
vs.
a one-time
exposure that
causes damage
e.g. reaction to drugs
or medication
chronic exposure
damage occurs
after repeated
exposure
e.g. smoking,
asbestos
How Toxic is “Toxic?”
Chemicals may cause harm in many different ways:
•
•
•
•
•
•
•
•
Flammable
Explosive
Radioactive
Corrosive
Irritant
Carcinogenic
Mutagenic
Teratogenic
LD50
the lethal dosage for 50%
of the animals on which
the chemical is tested
There are various ways an LD50 can be
expressed. For example, acetone has
the following LD50s:
ORL-RAT LD50: 5,800 mg/kg
IHL-RAT LD50: 50,100 mg/m3h
SKN-RBT LD50: 20 g/kg
LD50 Example
Chemical A: LD50 = 3.2 mg/kg
Chemical B: LD50 = 48 mg/kg
Which is more toxic?
Chemical A is more toxic because LESS is
necessary to kill half of a given population
Science
The Functions of Science
pure science
applied science
the search for
knowledge; facts
using knowledge
in a practical way
e.g., properties of
aluminum
strong
lightweight
good conductor
Corning Glass
NASA’s Problem
Design a material
that is clear and can withstand extreme differences
in temperature without failing (cracking).
Corning Glass Company
FAILED…but
SUCCEEDED at making
great cookware that can
withstand extremes in temperature.
Design a face shield
to protect and provide
clear vision.
Aluminum Mining
4-6 pounds
bauxite
• 1850s: aluminum sold
for $500 / lb
• Charles Martin Hall
• Developed method to
extract aluminum from
bauxite
• Hall’s method
– As a result, $0.30/lb
+
current
= 1 lb Al
Science attempts to establish
cause/effect relationships
Science can NEVER prove a
cause/effect relationship, only make a
correlation…
risk-benefit analysis
weigh pros and cons before deciding
Because there are many considerations for
each case, “black/white thinking” rarely
applies. It is usually shades of grey.
How does
scientific
knowledge
advance?
1. curiosity
2. determination
3. persistence
4. good observations
The Scientific Method
** Key: Be a good observer.
observation
uses the five
senses
inference
involves a judgment
or an assumption
Types of Data
Observations are also called data.
qualitative data
-- descriptions
e.g., colorless liquid
(vs. clear liquid)
quantitative data
-- measurements
e.g., 17 mL; 83oC
Candle Observation Activity
A Description of a
Burning Candle
A photograph of a burning candle is shown1 in the upper right corner. The candle is cylindrical2 and
has a diameter3 of about 3 cm. The length of the candle was initially about 16 centimeters4, and it
changed slowly5 during observation, decreasing about 1 cm in one hour6. The candle is made of a
translucent7, white8 solid9 which has a slight odor10 and no taste11. It is soft enough to be scratched
with the fingernail12. There is a wick13 which extends from top to bottom14 of the candle along its
central axis15 and protrudes about 5 mm above the top of the candle16. The wick is made of
three strands of string braided together17.
A candle is lit by holding a source of flame close to the wick for a few seconds. Thereafter the
source of flame can be removed and the flame sustains itself at the wick18. The burning candle
makes no sound19. While burning, the body of the candle remains cool to the touch20 except near
the top. Within about 1.5 cm of the top the candle is warm21 (but not hot) and sufficiently soft
to mold easily22.
The flame flickers in response to air currents23 and tends to become quite smoky while flickering24.
In the absence of air currents, the flame is of the form shown in the photograph, though it retains some
movement at all times25. The flame begins about 2 mm above the top of the candle26, and at its
base the flame has a blue tint27. Immediately around the wick in a region about 2 mm wide and
extending about 5 mm above the top of the wick28 the flame is dark29. This dark region is roughly
conical in shape30. Around this zone and extending about 1 cm above the dark zone is a
region which emits yellow light31, bright but not blinding32. The flame has rather sharply defined
sides33 but a ragged top34. The wick is white where it emerges from the candle35, but from the base
of the flame to the end of the wick36 it is black, appearing burnt, except for the last 0,5 cm, where it
glows red37. The wick curls over about 3 mm from its end38. As the candle becomes shorter, the wick
shortens too, so as to extend roughly a constant length above the top of the candle39. Heat is emitted
by the flame40, enough so that it becomes uncomfortable in 10 to 20 seconds if one holds his finger
10 cm to the side of the quiet flame41 or 10 – 12 cm above the flame42.
Parts of the Scientific Method
Identify an unknown.
Make a hypothesis: a testable prediction
Repeatedly experiment to test
hypothesis.
procedure: order of events in
experiment (i.e., a recipe of
what was done)
variable: any factor that could
influence the result
A Scientific
Experiment
Experiments must be controlled:
Only one variable can change at a time
Independent variable: a variable you control and
manipulate (x-axis)
Dependent variable: the variable you measure
as you change I.V. (y-axis)
conclusion: must be supported with
evidence from the data collected
A Controlled Experiment?
Make observation
Scientific
Method
Ask question
Develop
hypothesis
Test hypothesis
with further
experiments
Test hypothesis
with an
experiment
Revise
hypothesis
Analyze data
and draw
conclusions
Hypothesis
IS
supported
Wysession, Frank, Yancopoulos,
Physical Science Concepts in Action, 2004, page 8
Hypothesis
is NOT
supported
Develop
theory
Scientific Law vs. Scientific Theory
law: states what happens, i.e., a relationship
between various quantities
-- Laws are often written in
G m1 m2
Fg 
2
the form of… an equation.
r
-- e.g., Newton’s law of gravity,
laws of conservation
theory: tries to explain WHY or
HOW something happens
-- based on current evidence
-- e.g., Theory of Gravity,
Atomic Theory
a scanning tunneling
microscope (STM)
images of nickel atoms
taken by an STM
Phlogiston Theory of Burning
1. Flammable materials contain phlogiston
2. During burning, phlogiston is released
into the air
3. Burning stops when…
…object is out of phlogiston, or
…the surrounding air contains
too much phlogiston.
(superceded by combustion theory of burning)
Rob L. Brown, Sr. or Mary H. Brown
1007 Shady Lane
Normal, Illinois 61761
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Date
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$
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Chemistry
The Beginning
Early practical chemistry:
household goods, weapons,
soap, wine, basic medicine
The Greeks believed there
were four elements
___
___
D
D
earth
wind
fire
~
water
D
Alchemy
(~500 – 1300 C.E.)
the quest for the Philosopher’s Stone
(the elixir, the Sorcerer’s Stone)
Allegedly, this substance would turn
cheap metals into gold
Alchemical symbols for substances…
GOLD
SILVER
COPPER
IRON
.
..
...
....
.....
SAND
transmutation: changing one substance
into another
Philosopher’s
Stone

COPPER
GOLD
In ordinary chemical reactions… we cannot
transmute elements into different elements
Alchemy was practiced in many regions of the
world, including China and the Middle East.
Alchemy arrived in western Europe
around the year 500 C.E.
Modern chemistry evolved from alchemy.
Contributions of alchemists:
• experimental techniques
• new glassware
• information about elements
• developed several alloys
What is
chemistry?
the study of matter
and its changes
Areas of Chemistry
organic
the study of carbon
containing compounds
inorganic
studies everything
except carbon
e.g., compounds
containing metals
biochemistry
the chemistry of
living things
physical
measuring physical
properties of
substances
e.g., the melting
point of gold
Careers in Chemistry
•
•
•
•
•
•
research (new products)
production (quality control)
development (manufacturing)
chemical sales
software engineering
teaching
The skills you will develop by an earnest study
of chemistry will help you in any career field.
The Scope of Chemistry
bulk chemical manufacturing
acids, bases, fertilizers
**sulfuric acid (H2SO4) = #1 chemical
petroleum products
fuels, oils, greases, asphalt
pharmaceuticals
1 in 10,000 new drugs
gets FDA approval
synthetic fibers
nylon, polyester, rayon , spandex
Chemistry impacts: everyone
all fields of endeavor
Government Regulation of Chemicals
The various levels of government regulate
chemicals to protect the:
environment
EPA
worker
OSHA
consumer
FDA
USDA
CPSC
Manipulating Numerical Data
Graphs
Bar Graph
shows how many of something
are in each category
Chemistry Grades
# of students
10
8
6
4
2
0
A
B
C
D
F
Pie Graph
shows how a whole is broken into parts
Percentage of
Weekly Income
Entertainment (40%)
Food (25%)
Clothing (20%)
Savings (15%)
Line Graph
shows continuous change
Stock Price over Time
Share Price ($)
60
50
40
30
20
10
0
Jan
Feb
Mar
Apr
Month
In chemistry…you will always use a line graph.
Elements of a “good” line graph
Temp. v. Vol. for a Gas at Constant
Pressure
2. axes labeled,
with units
3. neat
4. use the
available space
Volume (L)
1. title
10
9
8
7
6
5
4
3
2
1
0
120
140
160
180
200
Temp. (K)
220
240
Graphing HW
Total Distance Cycled (km)
9 a.m.
12
10 a.m.
23
11 a.m.
33
noon
42
1 p.m.
50
2 p.m.
57
3 p.m.
63
4 p.m.
68
Time
80
Distance Cycled (km)
8 a.m.
Total Dist.
cycled (km)
0
70
60
50
40
30
20
10
0
8 a.m.
9 a.m.
10 a.m.
11 a.m.
noon
1 p.m.
2 p.m.
3 p.m.
4 p.m.
Time (h)
Extrapolation: predicting a pattern outside of a data set using the graph
Interpolation: estimating a data point within the set of data using the
pattern of the graph
Essential Math
of Chemistry
Scientific Notation
…used to express very large or very small
numbers. Also used to maintain correct SF.
(# from 1 to 9.999) x 10exponent
= 8 x 10 x 10
= 8 x 102
2531 = 2.531 x 10 x 10 x 10
= 2.531 x 103
0.0014 = 1.4 10 10 10
= 1.4 x 10–3
Form:
800
  
(-) exponent = number < 1
(+) exponent = number > 1
Put in standard form
1.87 x 10–5 = 0.0000187
3.7 x 108 = 370,000,000
7.88 x 101 = 78.8
2.164 x 10–2 = 0.02164
Change to scientific notation
12,340 = 1.234 x 104
0.369 = 3.69 x 10–1
0.008 = 8 x 10–3
1,000,000,000 = 1 x 109
6.02 x 1023 = 602,000,000,000,000,000,000,000
Using the Exponent Key
EE
EXP
The EE or EXP or E key means “times 10 to the…”
How
How to
to type
type out
out 6.02
6.02 xx10
102323::
6
0
.
2
EE
2
3
not…
WRONG!
6
0
.
yx
2
2
3
or…
6
WRONG!
.
0
2
x
1
and not…
6
.
0
EE
2
3
TOO MUCH WORK.
0
2
x
1
0
yx
2
3
Also, know when to hit your (–) sign.
(before the number,
after the number,
or either one)
1.2 x 105

2.8 x 1019
Type this calculation in like this:
1
.
2
EE
5
2
.
8
EE
1

9
=
Calculator gives… 4.2857143 –15
or… 4.2857143 E–15
This is NOT written… 4.3–15
But instead is written… 4.3 x 10–15 or
4.3 E –15
7.5 x 10–6 (–8.7 x 10–14) = –6.5 x 10–19
4.35 x 106 (1.23 x 10–3) = 5.35 x 103 or 5350
5.76 x 10–16

9.86 x 10–4 = 5.84 x 10–13
8.8 x 1011 x 3.3 x 1011 = 2.9 x 1023
Accuracy and Precision
All numerical data are the result
of uncertain measurements.
precision: a measure of the degree of
fineness of a measurement; it
depends on the extent to which the
instrument is calibrated
e.g.,
8m
vs. 8.00 m
vs. 8.00000 m
When repeated, precise measurements yield
similar answers each time.
e.g., precise…
0.653 m
0.652 m
0.654 m
imprecise…
0.7 m
0.8 m
0.6 m
A good rule of thumb is…
It is the % difference that is important.
accuracy: how close a measured
value is to the true value
Three types of error can affect accuracy.
human error: mistake in reading instrument
or recording results
-- minimize with repeated measurements
method error: using measuring instrument improperly
e.g., parallax in measuring with a meter stick
instrument error: measuring device is
improperly calibrated
e.g., bathroom scale that always reads 5 lbs. too heavy
Significant Figures
about…
A student is combining separate water
samples, all of differing volumes, into one
large bucket. Samples A, B and C are 25.5
mL, 16.37 mL and 51 mL, respectively.
Once combined, what is the total volume of
all the samples?
92.87 mL
NO!
Because the samples were each measured
with a different level of precision, we must
factor that into our calculations by identifying
what are called significant figures.
Measurement and Precision
• The last digit of any measured number is
assumed to be an estimate (uncertain)
• The second to last digit is assumed to be
known with certainty(think dashes…)
A (25.5 mL) B (16.37 mL) C (51 mL)
26
60
50
25
16.4
16.3
Identifying Significant Figures
Counting SF in a number
Non-zero numbers: ALWAYS count as SF
Zeroes
Relative
to the
non-zero
numbers
Left: NEVER count as SF (0.000345)
Middle: ALWAYS count as SF (5001)
Right: sometimes…
w/ decimal point: count as SF (25.10)
w/o decimal point: DO NOT count as SF (8200)
Exact Numbers: IGNORE SF
(assumed to have an infinite number of SF)
Counts (28 students in this class)
Constants (1 mol = 6.022 x 1023)
Conversions (1 in = 2.54 cm)
How many Sig Figs?
Measurement
Number of SF
Measurement
Number of SF
25 g
2
0.12 kg
2
0.030 kg
2
1240560. cm
7
1.240560 x 106 mg
7
6000000 kg
1
6 x 104 sec
1
6.00 x 106 kg
3
246.31 g
5
409 cm
3
20.06 cm
4
29.200 dm
5
1.050 m
4
0.02500 g
4
Now, determine the # of SF in Part A and B of the Sci. Not. HW (5 min)
Sig Figs with Calculations
Note: For any calculations, always perform the entire
calculation without rounding, and then round the final answer.
Addition/Subtraction
• Round the answer to the LEAST number of
decimal places found (least precise)
11.31 + 33.264 + 4.1 = 48.674 → rounded to 48.7
Multiplication/Division
• Round the answer to the smallest number of
SF found
5.282 x 3.42 = 18.06444 → rounded to 18.1
(3.42 only has 3 SF)
Back to the original question…
A student is combining separate water
samples, all of differing volumes, into one
large bucket. Samples A, B and C are 25.5
mL, 16.37 mL and 51 mL, respectively.
Once combined, what is the total volume of
all the samples?
25.5 mL + 16.37 mL + 51 mL = 92.87 mL
93 mL
Could I write that as 93.0? NO!
Round to the correct number of significant figures.
Calculator
says…
2 sig. figs.
3 sig. figs.
5 sig. figs.
75.6
76
75.6
75.600
0.528396
0.53
0.528
0.52840
387600
390,000
388,000
* 3.8760 x 105
4200
4,200
* 4.20 x 103
4.2000 x 103
8.4845E-4
8.5 x 10–4
8.48 x 10–4
8.4845 x 10–4
* = requires scientific notation
Units must be carried into the
answer, unless they cancel.
5.2 kg (2.9 m) = 0.64 kg*m
(18 s)(1.3 s)
s2
4.8 g (23 s)
(18 s)(37 s)
= 0.17 g
s
Solve for x.
x+y=z
x and y are connected by
addition. Separate them
using subtraction. In general,
use opposing functions to
separate things.
x+y=z
–y –y
The +y and –y cancel on
the left,
leaving us with…
x=z–y
Numerical Example
Solve for x.
x – 24 = 13
x and 24 are connected by
subtraction. Separate
them using the opposite
function: addition.
x – 24 = 13
+24 +24
The –24 and +24 cancel
on the left,
leaving us with…
x = 37
Solve for x.
x and k are connected by
multiplication. Separate
them using the opposite
function: division.
The two k’s cancel on
the right,
leaving us with…
F=kx
()
()
__
1
__
1
F=kx
k
k
(or)
F=kx
k k
__
F
x=
k
Numerical Example
Solve for x.
x and 7 are connected by
multiplication. Separate
them using the opposite
function: division.
The two 7’s cancel on
the right,
leaving us with…
8=7x
()
()
__
1
__
1
8=7x
7
7
(or)
8=7x
7 7
__
8
x=
7
Solve for x.
One way to solve this
is to cross-multiply.
Then, divide both
sides by TR.
The answer is…
___
BA = ___
TR
x
H
BAH = xTR
( )
( )
___
1 BAH = xTR ___
1
TR
TR
BAH
x = ___
TR
Solve for T2, where…
P
1V1
____
=
P1 = 1.08 atm
T1
P2 = 0.86 atm
____
1 PVT =
V1 = 3.22 L
P1V1 1 1 2
V2 = 1.43 L
P2V2T1
T1 = 373 K
( )
P
2V 2
____
T2
( )
____
1
P1V1
P2V2T1
______
T2 =
P1V1
(0.86
atm)(1.43 L)(373 K)
_____________________
T2 =
= 130 K
(1.08 atm)(3.22 L)
SI Prefixes
kilodecicentimilli-
(k)
(d)
(c)
(m)
1000
1/
10
1/
100
1/
1000
Also,
1 mL = 1 cm3 and 1 L = 1 dm3
You will be responsible for knowing these!
Conversion Factors and
Unit Cancellation
How many cm are in 1.32 meters?
equality: 1 m = 100 cm
(or 0.01 m = 1 cm)
conversion factors:
______
1m
100 cm
or
1.32 m 100 cm
1m
100 cm
______
1m
= 132 cm
We use the idea of unit cancellation
to decide upon which one of the two
conversion factors we choose.
How many m is 8.72 cm?
equality: 1 m = 100 cm
conversion factors:
______
1m
100 cm
8.72 cm
or
1m
100 cm
100 cm
______
1m
= 0.0872 m
Again, the units must cancel.
How many kilometers is 15,000 decimeters?
15,000 dm
1m
10 dm
1 km
1,000 m
= 1.5 km
How many seconds
is 4.38 days?
( )(
24 h
4.38 d ____
1d
)( )
60
min
_____
1h
60 s
____
= 378,432 s
1 min
If we are accounting for significant
figures, we would change this to…
3.78 x 105 s
4. Convert 41.2 cm2 to mm2
Recall that…
(1 cm)2 = (10 mm )2
41.2 cm2 102 mm2 =
1 cm2
4,120 mm2
SI-US Conversion Factors
Equality
Conversion Factors
Length
2.54 cm = 1 in.
2.54 cm
1 in
and
1 m = 39.4 in.
39.4 in
1m
and
946 mL = 1 qt
946 mL
1 qt
and
1 qt
946 mL
1 L = 1.06 qt
1.06 qt
1L
and
1L
1.06 qt
and
1 lb
453.6 g
and
1 kg
2.20 lb
1 in
2.54 cm
1m
39.4 in.
Volume
Mass
453.6 g = 1 lb
1 kg = 2.20 lb
453.6 g
1 lb
2.20 lb
1 kg
Simple Math
with
Conversion Factors
Find area of rectangle.
4.6 cm
A=L.W
= (4.6 cm)(9.1 cm)
= 42
9.1 cm
2.
cm cm
Convert to m2.
cm.cm
1m
42 cm2 ______
100 cm
(
)
= 0.0042 m2
(
)
= 4200 mm2
10 mm
Convert to mm2. 42 cm2 ______
1 cm
2
2
For the rectangular solid:
Length = 14.2 cm
Width = 8.6 cm
Height = 21.5 cm
Find volume.
V=L.W.H
= (14.2 cm)(8.6 cm)(21.5 cm)
= 2600 cm3
Convert to mm3.
2600
cm3
(
)
10 mm
______
1 cm
3
= 2,600,000 mm3
= 2.6 x 106 mm3
mm and cm differ by a factor of………. 10
mm2 “ cm2 “
“ “
“
“ ………. 100
mm3 “ cm3 “
“ “
“
“ ………. 1000
Density
 how tightly packed the particles are
mass
Density =
volume
m
 D
V
m
D
Typical units:
g/cm3 for solids
V
g/mL for fluids
liquids
and gases
Glass: liquid or solid?
To find volume, use…
1. a formula
V = p ∙ r2 ∙ h
V = l∙w∙h
2. water displacement
Vinitial
Vfinal
V = ?
Vobject = Vfinal – Vinitial
** Density of water = 1.0 g/mL = 1.0 g/cm3
Things that are “less dense” float
in things that are “more dense.”
(And things that are “more dense” sink
in things that are “less dense.”
D < 1 g/cm3
D > 1 g/cm3
D < 1 g/cm3
D < 1 g/cm3
The density of a liquid or solid is nearly constant,
no matter what the sample’s temperature
Density of gases is highly dependent on temperature
Will Bowling Balls sink or float in
If DBB > 1, it will sink H2O? If DBB < 1, it will float
21.6 cm in diameter
Vsphere = 4/3 p r3
V = 4/3 p (10.8 cm)3
V = 5,276.7 cm3
m
D
m=DV
V
m = (1.00 g/cm3)(5276.7 cm3)
m = 5276.7 g
Since the mass of a BB varies, let’s figure
out at what mass it will sink v. float
…or 11.6 lbs
Density Calculations
1. A sample of lead (Pb) has mass
22.70 g and volume 2.000 cm3.
Find sample’s density.
m
D
V
m
22.7 g
g
D 

3 = 11.35
V
2.0 cm
cm3
2. Another sample of lead occupies 16.2 cm3
of space. Find sample’s mass.
V
g
3

 = 184 g

11.35
16.2
cm
m=DV
3
cm
Indiana Jones
Density
• Watch the famous opening scene to
Indiana Jones and the Raiders of the Lost Ark
• The “pure gold” idol has a density of 19.3
g/cm3. How much would it mass?
19,300 g
• Indy replaces the idol with a bag of sand
(density = 2.5 g/cm3). Why did he activate the
booby trap? How much sand should he have
used?
7,720 cm3 or 7.72 L!
• Did you see that toss at the end!? How much
would the idol weigh in lbs? (2.2 lb per kg) 42.5 lbs!
m
3. A 119 g solid cylinder has radius
1.80 cm and height 1.50 cm. Find
sample’s density.
1.8 cm
1.5 cm
m
D
V
V = p r2 h
= p (1.8 cm)2(1.5 cm)
3
m
=
15.268
cm
D 
V
g
119.5 g

3 = 7.79
cm3
15.268 cm
m
8.2 cm
4. A 153 g rectangular solid
has edge lengths 8.20 cm,
5.10 cm, and 4.70 cm. Will
this object sink in water?
5.1 cm
4.7 cm
(Find the object’s density and compare it to water’s density.)
V=lwh
m
D
= 8.20 cm (5.10 cm)(4.70 cm)
V
= 196.55 cm3
153 g
m
g

D 
3 = 0.778
3 < 1 No; it floats.
V 196.55 cm
cm
Galilean Thermometer Problem
On a cold morning, a teacher walks into a
cold classroom and notices that all bulbs
in the Galilean thermometer are huddled
in a group. Where are the bulbs? At the
top of the thermometer, at the bottom or
elsewhere?
D1 1. Bulbs have essentially fixed masses
D2
D3
D4
D5
and volumes. Therefore, each bulb
has a fixed density.
2. The surrounding liquid has a fixed
mass, but its volume is extremely
temperature-dependent.
3. The density of the liquid can be written as… D1
mliq
Dliq 
Vliq
…if the liquid is cold:
mliq
Vliq
=
Dliq
D2
so…
D3
…but if it’s hot:
mliq
Vliq
=
On a cold morning,
where are the bulbs? AT THE TOP
Dliq
D4
D5
Osmium
76Os
Basic Concepts in Chemistry
chemical: any substance that takes part in,
or occurs as a result of,
a chemical reaction
*All matter can be considered to be
chemicals or mixtures of chemicals.
chemical reaction: a rearrangement of
atoms such that…
“what you started with” reactants
differs from
“what you end up with” products
Products
Reactants
carbon
methane + oxygen 
+ water
dioxide
CH4(g) + 2 O2(g)  CO2(g) + 2 H2O(g)

Products
Reactants
sodium + water  hydrogen +
sodium
hydroxide
2 Na(s) + 2 H2O(l)  H2(g) + 2 NaOH(aq)

Law of Conservation of Mass:
total mass
total mass
=
of products
of reactants
Pmass = Rmass
2 Cu + H2O + CO2 + O2  CuCO3 + Cu(OH)2
Copper “patina” is a mixture of
copper(II) carbonate and copper(II) hydroxide.
It has a characteristic green color.
Losing weight?
• Keeping the
Law of
onservation of
mass in mind…
• When you lose
weight, where
does it go?
• Three ways, all
of which
involve
excretion
synthesis:
putting simpler
substances
together, usually
in many steps,
to make
something more
complex
A proposed organic synthesis
of tetrahydrocannabinol (THC)