CH. 19

Two pairs of electrons involved in forming chemical bonds

Bonding pairs

The melting & boiling points of a _____ molecule are much higher than those of a _____ molecule.

polar, non-polar

What percentage of water are human bodies?

60-75%

What percentage of Earth's surface is water?

75%

What is the chemical formula for water?

H2O

Frozen water (ice) has a organized structure that resembles what? Why?

A honeycomb; each water molecule forms hydrogen bonds with 4 other molecules

As temperature ____, the organized structure of the hydrogen bonds among water molecules ____.

Decreases, increases

An intermolecular force between the hydrogen on one molecule to an atom on another molecule

Hydrogen bond

As temperature ____, the organized structure of the hydrogen bonds among water molecules ____.

Increases, decreases

Other two pairs of electrons not involved in forming chemical bonds

Lone pairs

What type of molecule is methane (CH4)?

Non-polar

Molecule that doesn't have distinctly charged poles

Non-polar molecule

What type of molecule is ammonia (NH3)?

Polar

What type of molecule is water?

Polar

Molecule that has a negative & positive end or pole

Polar molecule

What is the shape of a water molecule?

Pyramid/ Tetrahedron/ V

Are hydrogen bonds relatively weak or strong? Why?

Weak; they constantly break & reform as water molecules collide