Properties of Water

Question 1

What are some strange characteristics of water?

Answer 1

• Solid water (ice) is less dense than liquid water; it floats on water
• Water is a molecular compound, with two O-H bonds which consist of two elections being shared

O is missing two; H on two sides are positives

Question 2

Explain the uneven sharing of electrons in water.

Answer 2

oOo (not on direct ends, the hydrogen atoms are almost on “one side”)

• Oxygen hogs the electrons in covalent bonds.
• Oxygen has a greater ability to attract shared electrons towards it instead of hydrogen
• Because of its ability to attract this pair, electrons spend more time near the oxygen atom than the hydrogen atom

RESULT:
- Electrons spend more time near the oxygen atoms, so the oxygen end has a slightly negative charge δ-
- The hydrogen atoms do not spend as much time with the electrons, so it has a slightly positive charge δ+

δ = slight or partial charges (lowercase delta)
Partial positive, δ+. Partial negative, δ-.

Question 3

What is the polarity of water?

Answer 3

Polar Molecule: a molecule with a permanent separation of charge across a bond or molecule, resulting in a positive end and a negative end.

WATER IS A POLAR MOLECULE; it has two poles:
- A positive pole (δ+), the hydrogen end
- A negative pole (δ-), the oxygen end

Since there are two poles in the molecule, we call it a dipole

Question 4

What happens as a result of water’s polarity?

Answer 4

Water molecules are polar. As a result, water molecules are attracted to one another. The hydrogen end of one water molecule is attracted to the oxygen end of another water molecule. The attraction is called a hydrogen bond (when you have an O and H bond)

As a result, solid H2O organizes into a hexagonal crystal lattice. They have a big empty space in the center, taking up less space than liquid water, where they can slide past and tumble each other.

Question 5

What are intermolecular forces?

Answer 5

Bonds that act between molecules. Ex: hydrogen bonds

Question 6

What are intramolecular forces?

Answer 6

Bonds that act within molecules. Ex: covalent bonds

Question 7

What is a molecule?

Answer 7

An electrically neutral group of atoms joined together by chemical bonds.

Ex: O2, CH4, H20

Question 8

What are the effects of hydrogen bonding?

Answer 8

• Water’s high melting and boiling points
• High specific heat capacity; you have to jiggle all of the water molecules
• Ice floats on liquid water (most substances’ solid form will be more dense than that of their liquid form)
• Water’s High Surface Tension
• A good solvent (dissolving polar molecules and ionic compounds)
• Capillary action (paper towel soaks up water no matter where)