College Bio: Chapter 2

Matter

Anything that takes up space and has mass

Element

Pure substance that cannot be broken down

4 elements that make up 96% of living matter

oxygen, carbon, nitrogen, and hydrogen

Trace elements (4% of living matter)

Calcium, phosphorus, sulfur, potassium, iron, and iodine

Structure of an atom

Neutrons and protons in nucleus; electrons within cloud

Covalent bonding

sharing of electrons (polar is unequally)

Ionic bonding

Electron jumps to another atom’s valence shell (cation is +) (anion is -)

Hydrogen bonding

Positive and negative ends of molecules attract to each other (have to involve H with Fl, N, O)

Van Der Waals

weak bonding that is formed between atoms/molecules when within close proximity to each other

Cohesion V. Adhesion

Cohesion is when water attracts to water; adhesion is when water attracts to other surfaces

Surface Tension

The cohesion of water molecules causes them to form a semi-permeable membrane from the hydrogen bonds of water

Solute V. Solvent

Solute dissolves; solvent does the dissolving

Universal Solvent

Water due to its polarity (negative and positive ends), which lets it easily pull apart other polar substances

Hydrophilic Vs. Hydrophobic

Hydrophilic: water loving

Hydrophobic: water hating

pH Scale

Measures the concentration of H+ ions within a substance to determine if it is basic (8-14) or acidic (0-6). Water is the only neutral (7)

Example of an acid

Lemon, stomach acid, HCl

Example of a base

Bleach, baking soda, POH