Sections 1.1, 1.2, and 1.9

1
Lecture 1

• Sections 1.1, 1.2, and 1.9

2
Memorization Assignment

• Names (spelled correctly)
• H, He, Li, Be, B
• C, N, O, F, Ne
• Na, Mg, Al, Si, P

3
Now Go the Other Direction

• No peeking at the periodic table
• Phosphorus, silicon, aluminum, magnesium, sodium
• Neon, fluorine, oxygen, nitrogen, carbon
• Boron, beryllium, lithium, helium, hydrogen

4
Section 1.1

• Any questions?

5
The Hydrogen Balloon

• 2H2(g) O2(g) ? 2H2O(g)
• What does it mean?
• Draw a picture (use circles for atoms)
• Put 10 hydrogen molecules in the left-hand box
  and the appropriate number of oxygen and water
  molecules in the other boxes

6
Section 1.2

• Discussion Questions
• What is the difference between a qualitative and
  a quantitative observation?
• See page 5, step 1 in scientific method
• What is a hypothesis?
• See page 5, step 2 in scientific method
• Point 2 toward top of page is incorrect.
• What is a theory?
• See page 6
• What is the difference between a law and a
  theory?
• See page 6

7
The Scientific Method Triangle
8
Example

• Gravity
• Observation and experiment
• What goes up must come down
• Motion of planets
• Summary
• Law of Universal Gravitation
• Explanation
• Theory of Gravitation
• See the Physics Department

9
Example

• Evolution
• Observation and experiment
• Fossil record
• MRSA (methicillin-resistant staphylococcus
  aureus)
• Human genome and mouse genome
• Summary
• Law of Natural Selection
• Explanation
• Theory of evolution
• See the Biology and Geology Departments

10
Science A Healthy Skepticism

• Try this new herbal supplement! It will cure
  _______ (whatever ails you).
• Has it been tested in a double-blind research
  study?
• Or is it supported only by testimonials?
• Most people get better no matter what they do!
• Have the results been published in a
  peer-reviewed scholarly journal?

11
More Healthy Skepticism

• Diet and weight control
• Burn more than you eat, you lose weight
• Eat more than you burn, you gain weight
• Its that simple
• Forget the fad diets, the weight-loss gimmicks
• Alternative (unproven) medicine
• http//www.quackwatch.org

12
Section 1.9

• Discussion Questions
• What is the key difference between a compound and
  a mixture?
• See pages 25, 27
• You can write a formula for a compound (and an
  element)
• What are the two kinds of pure substances?
• See page 27
• What is the difference between a chemical change
  and a physical change?
• See pages 26, 27

13
Classification of Matter

• Pure and impure matter
• Pure matter (substances)
• Constant composition and properties
• Composition can be expressed by a formula
• Decomposed into simpler substances by chemical
  changes (refers only to compounds)
• Impure matter (mixtures)
• Variable composition and properties
• Separated into components by physical changes
• You just cant trust the labels!

14
Physical and Chemical Changes

• At this point, its difficult to tell the
  difference.
• Sometimes its hard for chemists to tell the
  difference!
• The key question is whether new substances
  (elements or compounds) are produced.
• Bunsen burner
• Hydrogen balloon
• Fe, Al, Mg
• Ping pong balls

15
Impure Matter (Mixtures)

• Heterogeneous and Homogeneous
• Heterogeneous
• Nonuniform distribution of components
• Its chunky (but at what level?)
• Homogeneous (Solutions)
• Uniform distribution of components at the
  microscopic (meaning molecular) level
• Caution about texts use of visibly (p. 25)

16
Separating Mixtures

• Distillation
• Filtration
• Chromatography
• Dionex Corporation
• These are all physical changes

17
Pure Matter (Substances)

• Elements and compounds
• Elements (Zn, O2, He, Mg, S8, etc.)
• Cannot be decomposed into simpler substances by
  chemical or physical changes (text quote)
• But what about O2 --- 2O ?
• What does simpler substances mean?
• Compounds (NaCl, C6H12O6, etc.)
• Decomposed by chemical changes

18
Questions and Discussion

• Active Learning Questions
• Answers not available in Solutions Guide
• Can be discussed here or in study groups