introduction to chemistry. chemistry the study of: the composition (make-up) of matter the changes...
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Introduction to Chemistry
Chemistry
The study of:
the composition (make-up) of matter
the changes that matter undergoes
The 5 Traditional Branches of Chemistry
Inorganic Organic Analytical Physical Biochemistry
Inorganic Chemistry
The study of chemicals that do not contain carbon.
Organic Chemistry
The study of chemicals that contain carbon.
Origin: study of chemicals in living organisms.
Analytical Chemistry
Composition of matter; measurable, identifies compounds/components
http://besg.group.shef.ac.uk/Facilities/Images/gcms.JPG
Example:Mass SpectrometerGas Chromatograph
Physical Chemistry
The study of : The mechanism The rate The energy transfer that happens when
matter undergoes change. Study of the interaction between two
elements Study of properties and changes of
matter and energy
Biochemistry
Study of processes that take place in organisms.
Understand the structure of matter found in the human body and the chemical changes that occur in cells
Science
What? Why?
How? When?
Science and Technology Theoretical Chemistry-Design of new
compound and new ideas; 2 categories: pure and applied
Science Pure Does not necessarily have an application;
just knowing for knowledge’s sake; research Technology Applied
Has practical applications in society Directed toward a practical goal/application Engineering
Alchemists (~300BC-1650 AD)China, India, Arabia, Europe, Egypt
•Aiming to:
Change common metals to gold.Develop medicines.
•Developed lab equipment.
•Mystical.
Antoine Lavoisier (France 1743-1794)
Regarded as the Father of Chemistry Designed equipment Used observations and measurements. Discovered nitrogen Law of Conservation of Mass
The Scientific Method
Steps followed during scientific investigations
Logical, problem solving technique
Fathers of the scientific method is Galileo Galilei and Francis Bacon
Scientific Method
Observation- recognition of a problem Visible or provable fact From that a question arises (problem
statement) Problem statement is a question that
compares variables Example: Does the amount of salt in water
affect the boiling temperature of water?
Scientific Method Hypothesis- a proposed explanation of an
observation an educated guess must be testable Is a statement NOT a question that expresses
the expected answer to the problem statement (what you think the results of the experiment will show) If you increase the amount of salt added to the
water, the boiling temperature will also increase because
Scientific Method Experiment- an organized procedure used
to test a hypothesis (measurement, data collection, manipulated and responding variables) Planned way to test the hypothesis and find out
the answer to the problem posed Way to collect data and determine the value of
the dependent variable Compares independent variable to the
dependent variable Can only test one dependent variable at a time
Scientific Method
3 parts to an experiment Control-standard for comparison Variables
Independent Variable Dependent Variable
Constants-parts of your experiment that do not change
Scientific Method Independent Variable
A variable that changes unrelated to other factors
A variable we manipulate, change, on purpose A variable whose value we know before we start
an experiment Example: Does the amount of salt in water affect
the boiling temperature of water? We know how much salt we add to each amount of water before boiling so amount of salt is the independent variable
Scientific Method Dependent Variable
A variable that changes depending on some other factors
The variable we are trying to find out Variable whose value we do not know before we
start the experiment Example: Does the amount of salt in water
affect the boiling temperature of water? We do not know the boiling temperature to water once salt is added; must test to find this out
Scientific Method
Constants Does not change for the duration of the
experiment Remains the same Example: Does the amount of salt in
water affect the boiling temperature of water? We would not change the brand of salt or the amount of water (or type of water)
Scientific Method
Analyze Look for patterns in experimental data 2 types of data
Quantitative = numbers Qualitative = observations
Data presented via tables or graphs 3 types of graphs: circle (pie), bar, line
Scientific Method
The cafeteria wanted to collect data on how much milk was sold in 1 week. The table shows the results. We are going to take this data and display it in 3 different types of graphs.
Day Chocolate Strawberry White
Monday 53 78 126
Tuesday 72 97 87
Wednesday 112 73 86
Thursday 33 78 143
Friday 76 47 162
Scientific Method Bar Graph
A bar graph is used to show relationships between groups.
The two items being compared do not need to affect each other.
It's a fast way to show big differences. Notice how easy it is to read a bar graph.
Often used for counting.
Chocolate Milk Sold
53
72
112
33
76
0
20
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120
Monday Tuesday Wednesday Thursday Friday
Day
Am
ount
Sol
d
Monday TuesdayWednesday ThursdayFriday
Scientific Method Circle graph (a.k.a.
pie chart) Used to show how a
part of something relates to the whole.
This kind of graph is needed to show percentages effectively.
Sum of parts is 1 or 100%
Chocolate Milk Sold
Monday
Tuesday
Wednesday
Thursday
Friday
Scientific Method Line Graph
A line graph is used to show continuing data; how one thing is affected by another.
It's clear to see how things are going by the rises and falls a line graph shows.
Equation of line represents the data.
Chocolate MI lk Sold
0
20
40
60
80
100
120
Monday Tuesday Wednesday Thursday Friday
Day
Am
ount
Sol
d
Chocolate
Scientific Method Choosing the right graph for your data
Use a bar graph if you are not looking for trends (or patterns) over time; and the items (or categories) are not parts of a whole.
Use a pie chart if you need to compare different parts of a whole, there is no time involved and there are not too many items (or categories).
Use a line graph if you need to see how a quantity has changed over time. Line graphs enable us to find trends (or patterns) over time.
Scientific Method
Conclusion Presents the findings of the experiment,
what the data shows, the hypothesis and whether or not it was correct (supported) or incorrect (negated)
Theorizes why the observed pattern is so
Scientific Method
Communicate When scientists collaborate (work
together) and communicated, they increase the likelihood of a successful outcome Journals Internet Presentations/Speeches
Observations vs. Inferences Observation
Something you confirm, something you have seen, a fact
A piece of information about circumstances that exists or events that have occurred
Inference An abstract or general idea derived from
specific instances Idea, thought, concept, notion, opinion
Theory
A well tested explanation for a broad set of observations.
May use models. May allow predictions. Theories may change to explain new
observations or experimental data.
Law
A statement that summarizes results of observations, but does not explain them.
Concise statement that summarizes the results of many observations and experiments
Changes or is abandoned when contradicted by new experiments.
Note:
The order of the steps can vary and additional steps may be added.
“No number of experiments can prove me right;
a single experiment can prove me wrong.”
Albert Einstein
Math and Chemistry
Math- the language of Science SI System (Metric System) Factor Label Method (Dimensional
Analysis) Significant Figures Scientific Notation Manipulating Formulas
Units
SI Units – International System
Basic Units abbreviation
Length (meter) mMass (kilogram) kgTime (second) s
Solving Word Problems
Analyze List knowns and unknowns. Devise a plan. Write the math equation to be used.
Calculate If needed, rearrange the equation to solve
for the unknown. Substitute the knowns with units in the
equation and express the answer with units.
Evaluate Is the answer reasonable?