Chemical bonds

Intramolecular bonds (bonds between atoms in a molecule)

Covalent bonds (sharing of electrons)

Polar covalent

No electronegative difference so the electrons are shared equally

Example: H2O

The Oxygen has a higher electronegative pull so gains a partial negative and the Hydrogen gains a partial positive because being pulled by Oxygen.

Nonpolar covalent

Difference in electronegativity making the electrons unequally shared

Example: CH's

There is no difference in their electronegativity so no pull and no partial charge.

Ionic bonds (difference in electronegativity making it a complete charge)

Example: Na+ and Cl-

Na+ loses the one valence electron to complete the octet rule giving it one more proton than electrons

Cl- gains one electron to give it 8 valence electrons giving it one more electron than proton.

Intermolecular bonds (attraction between molecules) generally weak

Dipole-dipole interaction

The interaction between polar and polar molecules.

Example

Example: Hydrogen bonds

polar molecules interaction with Hydrogen atoms bonded to either F, O, or N because they have a high electronegativity.

water properties

Cohesion and adhesion

Cohesion- hydrogen bonds in water sticking to other water molecules.

Surface tension- the cohesion of water molecules hydrogen bonds ability to hold the surface of a liquid.

Adhesion- Hydrogen bonds clinging to other molecules

High specific Heat

The ability for heat to absorb or lose some of the substance to change its temperature

Water molecules abosrbe heat and break hydrogen bonds but they are close enough to reform and release heat. No kinetic heat increase

helps moderate temperature

High heat of vaporization

water absorbing a high amount of heat breaking hydrogen bonds to not reform but vaporize (gas) leaving cool molecules back

Expansion upon freezing

As temperatures decrease the hydrogen bonds start to expand away from each other forming the hydrogen bonds not breaking them.

Ice has a greater volume than its liquid form

So the ice will float in water and has the ability to insulate the temperature below ice so that organisms can still exist

Denser as a liquid than solid

water has a lower volume than ice so ice would float. So then water would have a higher density than ice. Creating a crystal structure

Universal solvent

Polar or ionic

nonpolar

pH

acidic

less than 7 with a higher H+ concentration

neutral

equal to 7 balance for organisms to live

basic

more than 7 with a lower H+ concentration

Example

Ion-dipole interaction

The interaction between polar and ionic molecules

Example: Na+ CL- and water molecules

the opposite partial charges are attracted to the opposite complete charge

Hydrophobic interaction

nonpolar molecules interaction when placed in a polar environment

Example: CH's in water

The CH's gather in an mutual agreement because they dislike water.

Van der Waals

weak interaction with nonpolar molecules

the electrons are not distributed evenly and create partial charges on each of the atom attracting as they get closer together.