Scientific Process and Chemistry

Evolution

States that living organisms are descendants of common ancestors

Emergence

“whole is MORE than just the sum of its parts”

Emergent Properties

New processes that only appear when 2 things are together in certain ways

Levels of Biological Organization 

Organelles → cells → tissues → organs/organ systems → organisms, populations, and communities → ecosystems → the biosphere

Method of Inquiry 

• limited to what is observable and measured

• systematic

Hypothesis

Testable explanation for observations based on available data, and is testable and verifiable

Prediction

What you expect to see when you test the hypothesis. (What outcomes you expect)

Theory

Broad explanation with significant support

Law

A statement of what always occurs under certain circumstances

Scientific Method

1. Observation →

2. Background →

3. Hypothesis leads to

4. Prediction →

5. Experiments →

6. Evalute → 4. Revise incorrect predictions → repeat and verify → ask a new question if sucessful

Electrons

• 25 of 92 elements essential to life, 4 of them being Carbon, Hydrogen, Nitrogen, and Oxygen is in 96% of living matter

• - 1 charge, move rapidly, subatomic particles

• determine how atoms interact

  • the further away e- is from nucleus, the more potential energy e- has which causes it to be excited and can be used to do work

Atoms

3 subatomic particles → protons, neurons, and electrons

electron shell

an electrons potential energy

valence shell

outermost shell, where bonds between electrons form and has to have 8(octet) e-’s

Chemical Bonds

Result from how atoms share electrons

Energy

Capacity to cause change

Molecules

Compounds with 2 or more atoms

Emergent Properties

Many compounds have different properties than their elements

Electronegativity

• Affinity for electrons and the way an atom attracts an electron

  • O2 is an example

Covalent Bond

• sharing of e-’s

• an intramolecular bond (within a molecule), STRONG bond

• types 

  • nonpolar → same electronegativity, sharing e-’s equally

  • polar → <2 diff, e- shared unequally

Ionic bond

• e- is taken away be element with >electronegativity

  • between charged atoms

  • intramolecular

  • one atom steals e- from another, bond formed between anion and cation

Van Der Waals forces

Develops because electrons are in constant motion which result in attractions between molecules

• ex: dipole-dipole, London - dispersion forces 

Intermolecular forces

interactions between molecules

Hydrogen Bonds

• REALLY strong dipole-dipole interaction

• stick polar covalent molecules together

  • “stickiness” between water molecules

  • polarity allows H2O molecules to form attraction to each other

    • water is polar → 1 molecule bonds with other water molecules

  • responsible for many properties of water

  • 4 emergent properties

Cohesion

Water molecules stick to each other

Adhesion

H2O molecules stick to other polar things

Moderates Temperature

• has high specific heat → hard to change temperature

• high heat of vaporization → hard to change state

Expands upon freezing

• H-bonds in ice are more “ordered”, makes “air pockets” (why ice floats)

• reaches its greatest air density @ 4℃

Universal Solvent - hydrophilic

• salts, ions, polar

Hydrophobic 

• “afraid” of water

• lipids

• nonpolar