What is Chemistry All About? How does this photo illustrate
what chemistry is all about?? Chemical reactions of
rusting/weathering/maybe a fire in the fireplace Physical states of
water Different types of materials: glass, wood, living material,
brick, snow
Slide 4
The Study of Matter and Change What is Matter? Anything that
has mass and takes up space (volume) Not Matter Light Energy
Emotions or Feelings Thoughts Electricity Sound
Slide 5
Pure Science Vs Applied Science Pure Science: For the sake of
the knowledge Studying butterflies just to know more Researcher
lives on a remote island to daily study the jungle trees Studying
ape behavior Applied Science: Using science to solve a particular
problem Scientist studying corn in fields to increase the yield for
farmers Scientist searching for a cancer cure
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Why is Pure Research Important? A Base of knowledge when needed
Keeps us current General not specific and possible commercial
Accidental Discoveries
Slide 7
Technology Application of Science for human benefit Good and
Bad Nuclear Technology Good: EnergyBad: Waste Computer Technology
Good: CommunicationBad: Wasted Time
Slide 8
Organic chemistry Inorganic chemistry Physical chemistry
Analytical chemistry Biochemistry Environmental chemistry
Industrial chemistry Polymer chemistry Theoretical chemistry
Thermochemistry Chemistry is traditionally broken into branches
that focus on specific areas such as :
Slide 9
This Class HS General Chemistry is Inorganic Inorganic: the
study of non-carbon based compounds Organic Chemistry: Study of
matter that contains carbon
Slide 10
The Scientific Method The scientific method is a systematic
approach used in scientific study, whether it is chemistry,
physics, biology, or another science.scientific method To solve
problems Not a set of rigid steps It is an organized process used
by scientists to do research, and provides methods for scientists
to verify the work of others.
Slide 11
Observations Gathering Information (Data) using the five senses
No trivial or unimportant observations Dont make inferences or
assumptions when you observe Qualitative data is obtained through
observations that describe color, smell, shape, or some other
physical characteristic that is related to the five senses.
Qualitative data Quantitative data is obtained from numerical
observations that describe how much, how little, how big or how
fast. Quantitative data
Slide 12
Controlled Experiment A test of a hypothesis Making
observations under controlled conditions Where only one variable at
a time is changed Systematic approach to test a hypothesis Parts of
An Experiment Variables: A condition changed in an experiment
Independent Dependent Constants: any factor not changed in an
experiment Control: Group/set up that has no changes made to it
Conclusion: A judgment based on the observations made in a
controlled experiment
Slide 13
Independent Variable Changed by the experimenter Allowed to
change The Cause in Cause and Effect Manipulated Variable Happens
First The waters temperature increased as more heat was applied.
The temperature of the solid caused the density of the solid to
change An increase in phosphorous helped the plants to grow
taller.
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Dependent Variable Changes in response to the change in the
independent variable Responding Variable Happens second The boiling
point increased as salt was added to the water The hamster grew two
inches with an increase in the hormone.
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Control A point of comparison in an experiment The group that
does NOT receive the treatment
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Constants Specifics that remain the same between the control
group and the experimental group Only the independent variable
should be changed by the experimenter Examples of Constants:
Slide 17
Conclusion A conclusion is a judgment based on the information
obtained from the experimentconclusion
Slide 18
Hypothesis and Experiment Hypothesis: A tentative explanation
of observations A tentative answer A statement to be tested by an
experiment Example: If I give the fish more hormone then they will
grow longer. Experiment: The test of a hypothesis A controlled set
of steps to test a hypothesis
Slide 19
Theory Vs Hypothesis A theory is a hypothesis that has stood
the test of repeated experiments An explanation of results Never
proven Can be disproven All theories are hypotheses. (True) All
hypotheses can become theories. (True) All hypotheses are theories.
(False)
Slide 20
Experiment Kate noticed that she could dissolve more sugar in
the tea when it was warm than when it was ice cold. She wondered if
this was true for all solids. She decided to design an experiment
to see if water temperature effects how much salt can be dissolved.
She chose table salt as her solid to test. She used water as her
solvent. Hypothesis: An increase in the temperature of the water
will allow more salt to dissolve, She placed 100 mL of water in
each of 10 250 mL beakers. She cooled the water in beaker # 1 to 10
degrees C. The water in beaker #2 was 25 degrees C. Beaker # 3
water was heated to 35 degrees C. Beaker # 4 water was heated to 45
degrees C. Beaker # 5 was heated to 55 degrees C.
Slide 21
Beaker # 6 65 degrees C Beaker # 7 75 degrees C Beaker # 8 85
degrees C Beaker # 9 95 degrees C Beaker # 10 100 degrees C
Slide 22
She added salt to each beaker while using a magnetic stirrer
which provided constant and uniform stirring until no more salt
would dissolve. She measured and recorded the amount of salt that
dissolved in each beaker. Her data is shown below.
Slide 23
Data Amount of water 100 mL Temp of Water (degrees C) Grams of
salt dissolved 11037 22537 33538 44538 55538 66538 77539 88540
99540 1010040
Slide 24
Identify the following Independent Variable Dependent Variable
Control Constants Possible conclusion Another hypothesis
Slide 25
Scientific Law Vs Theory Observable Fact True: Always observed
No known exceptions No explanation Explanation Tentative Can be
disproven
Slide 26
Development of a Theory Start with an observation that evokes a
question: Broth spoils when I leave it out for a couple of days.
Why? Using logic and previous knowledge, state a possible answer,
called a Hypothesis: Tiny organisms floating in the air must fall
into the broth and start reproducing. Perform an experiment or
Test: After boiling some broth, I divide it into two containers,
one covered and one not covered. I place them on the table for two
days and see if one spoils. Only the uncovered broth spoiled. Then
publish your findings in a peer-reviewed journal. Publication:
"Only broth that is exposed to the air after two days tended to
spoil. The covered specimen did not." Other scientists read about
your experiment and try to duplicate it. Verification: Every
scientist who tries your experiment comes up with the same results.
So they try other methods to make sure your experiment was
measuring what it was supposed to. Again, they get the same results
every time. In time, and if experiments continue to support your
hypothesis, it becomes a Theory: Microorganisms from the air cause
broth to spoil. Useful Prediction: If I leave food items open to
the air, they will spoil. If I want to keep them from spoiling, I
will keep them covered.
Slide 27
Chemistry is Central to our Lives Chemistry is about
composition, structure, function, and interaction of matter
Everything has composition, structure, function, and interaction.
All other sciences (biology, physics, geology, etc) have their
basis in chemistry
Slide 28
Mass Vs Weight Mass Weight Not influenced by gravity Changes
only when amount of matter changes Kilograms or grams Affected by
gravity W = mg g= 9.8 m/s 2
Slide 29
Your Mass Earth Moon M ass = 60 kg Gravity = 1/6 th the gravity
on Earth Mass = 60 kg Not affected by gravity
Slide 30
Weight Earth Moon m = 60 kg W = mg W = (6o kg)(9.8m/s 2 ) W =
588 Newtons m = 60 kg W = mg g = 9.8m/s 2 /6 = 1.63 m/s 2 W = (60
kg)(1.63m/s 2 ) W = 98 Newtons
Slide 31
Environment with No Gravity Weight only would change You would
weigh less Amount of Matter is not affected Mass stays the
same
Slide 32
Submicroscopic and Macroscopic Submicroscopic Macroscopic
Atomic Level What happens here determines the macroscopic What we
observe Determined by the submicroscopic (atomic) Chemist are
interested in how the atomic level determines the macroscopic
Slide 33
Substance is matter that has a definite composition. Also known
as a chemical Element Compound One type of atom Oxygen (O 2 ) Ozone
(O 3 ) Copper Two or more types of atoms Sodium chloride (table
salt) NaCl Ethyl alcohol H 2 O
Slide 34
Chance Discoveries Discoveries made by accident Not trying to
find an answer Examples Velcro Penicillin Teflon Chocolate Chip
Cookies The Microwave Oven Artificial Sweeteners Curiosity Drives
Discovery