USOE BOOK QUESTIONS Page 162 Properties of Water #’s 1-5

1. List three unique properties that water has due to hydrogen bonding. Cohesion: water sticks to water Adhesion: water sticks to other substances High boiling point: allows water to be liquid for all life forms on Earth Expands when freezes: crystalline structure makes water have a lower density when it freezes. This causes ice to float and lets life exist in cold climates.

2. Water can exist in all three states of matter. Why is water typically in the liquid form? Water has a high boiling point so it is found mostly in the liquid form.

3. Why is it essential for life that water is less dense when frozen than when liquid? All life needs liquid water. When water freezes it will float and protect the life in a frozen lake or pond.

4. Water always beads up on a freshly waxed car. Is this due to adhesion or cohesion? Both? Explain Both. Adhesion makes the water bead on the car surface. Cohesion causes the bead of water to form and grow into a bead.

Penny water lab: Adhesion and Cohesion

5. Why is water considered a polar molecule? The oxygen atom attracts the negatively charged electrons more than the hydrogen atoms. This causes the oxygen atom to have a slightly more negative charge and the hydrogen’s to be more positive. This slight difference in charge in a molecule is called polarity, making a water molecule polar. Higher boiling point for polar water

The End