1. 2.1 Properties of Water

2. Key Concepts and Vocabulary
What is the structure of a water molecule?
What are the important properties of water?
Why is water essential for life?
Vocabulary:
Polarity
Hydrogen bond
Adhesion
Cohesion
Specific heat
Solute
Solvent
Acid
Base

3. Structure of a Water Molecule
A water molecule contains two hydrogen atoms bonded to one oxygen atom
Draw a water molecule in the space below:
It looks like Mickey Mouse!

4. Polarity
Polarity – molecule that has two “poles,”– a positive and negative end.
In water, the oxygen atom has a negative charge, and the hydrogen atoms are positively charged.
Therefore water is a polar molecule

5. Bonding
Hydrogen bonds – the positive hydrogen of one water molecule is attracted to the negative oxygen of another water molecule.
Hydrogen bonds give water unique properties
Draw a diagram of the hydrogen bonds of water in the space below:

6. Properties of Water Cohesion - Water molecules stick to each other
Creates surface tension on water’s surface
What are some other examples of surface tension?

7. Properties of Water
Adhesion - Water molecules stick to other substances
Causes capillary action - the ability of water to climb tubes
In what organisms might capillary action be important?

8. Properties of Water
High Specific Heat - Large amounts of heat are needed to raise water’s temperature
Why?

9. Properties of Water
High heat capacity - Water absorbs heat as it evaporates
Helps to cool off organisms

10. Properties of Water
Density – solid water is less dense than liquid water.
Allows ice to float, preventing large bodies of water from freezing solid

11. Properties of Water
Universal Solvent - water can dissolve most substances
Why is this so important?

12. Solution Chemistry Solutions – a uniform mixture of two substances
Solute – the substance that is being dissolved
Solvent – the substance the solute dissolves into.

13. Acids and Bases Acid – a solution that releases H+ ions in a solution
Base – a solution that releases OH- ions in a solution
pH – the scale used to measure how acidic or basic something is.

16. Why is Water Important?
How much of the human body is water? The planet earth?
Why is water so important for living organisms?