1. Chemistry of Water

Question 1

Define Intramolecular

Give an example

Answer 1

The forces WITHIN a molecule.

Eg. hydrogen chloride

Bonds between the hydrogen and chlorine atoms

Question 2

Define Intermolecular Forces

Give an example

Answer 2

Forces BETWEEN molecules

Eg. water

The hydrogen bonds that conect each water molecule to another.

Question 3

What are Lewis Structures and what are they used for?

Answer 3

Lewis Structures show the bonding between atoms of a molecule, normally for covalently-bonded molecules.

Each dot represent the a valence electron and lines are drawn between atoms that are bonded together.

Non-bonding electrons are lone pairs.

Question 4

What are polar molecules?

Answer 4

Molecules that have a weak partial negative charge at one region of the molecule and a partial positive charge at another end of the molecule.

They also have a electronegativity difference of <1.7 and >0.3

Question 5

What is electronegativity?

Answer 5

Is the want for electrons. It is the power to attract electrons to itself.

Question 6

Evaluative Question:

Why does water have an unusually high boiling point?

Answer 6

Because there are many hydrogen bonds and lots of heat is required to overcome these bonds before the heat gets to the water molecules.

Question 7

Evaluative Question:

Why is ice less dense than liquid water? (In terms of hydrogen bonds)

Answer 7

The water moelcules are joined together by rigid hydrogen bonds, spacing the water molecules further apart, making it less dense.

As liquid water is warmer than ice, some of the hydrogen bonds have started to break, the water molecules begin to move and are closer together making it more dense.

Question 8

Evauative Question

True/ False

Ionic compounds are usually soluble in polar substances? Give an example

Answer 8

True

eg. sodium chloride dissolves in water

Question 9

True/False

In a covalent molecular compound, the attraction between molecules tends to be strong.

Answer 9

False:

Hydrogen bonds are much weaker.

Question 10

Multiple Choice:

The symbol 8+ is placed to which of the following?

A.) The less electronegative atom in a polar coavlent bond

B.) The more electronegative atom in a polar covalen bond

C.) A positive ion

D.) Nucleus

Answer 10

A.)The less electronegative atom in a polar coavlent bond

Question 11

Multiple Choice:

Which of the following best describes water H20?

A.) Ionic

B.) Nonpolar overall, with polar covalent bonds

C.) Polar overall, with polar covalent bonds

D.) Polar overall with non-polar covalent bonds

Answer 11

C.) Polar overall, with polar covalent bonds