Properties of water, pH, and Organic vs. Inorganic

Water striders can walk across the surface of calm water. Their feet push the surface of the water down slightly, but they do not break the surface. Why?

• The insects are light enough so they do not break the hydrogen bonds holding the water molecules together

• The insects actually use their wings to hover slightly above the water’s surface and they only skim it with their feet.

• The insect’s feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water’s surface.

• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

What word describes when water is attracted to other substances?

• cohesion

• adhesion

• capillary action

• surface tension

Why can water have no net charge but have slight charges in different parts of the molecule?

• The oxygen end is slightly negative and the hydrogen end is slightly positive
• The hydrogen end is slightly negative and the oxygen end is slightly positive
• The hydrogen and oxygen ends change in polarity
• Because it is hydrophobic

Why does water move from the roots to the leaves of plants?

• Water is pushed by solutes
• Capillary action pulls the water molecules like a chain
• Water is pulled by gravity
• Water’s cohesion causes it to “pull” towards the leaves

Attractions between water molecules are called

• Covalent bonds
• Ionic bonds
• Polar bonds
• Hydrogen bonds

The attraction that causes water and other liquids to form drops on thin films is called ________________. This is also water’s ability to be attraction to other water molecules.

• adhesion
• capillary action
• cohesion
• surface tension

What property of water helps to moderate earth's temperature?

• adhesion

• cohesion

• High Specific Heat

• Latent heat of vaporization

Why does ice float?

• As water freezes, it expands and its density decreases.
• As water freezes, it takes up more hydrogen from the atmosphere, causing it to have a greater buoyancy.
• As water freezes, air becomes trapped between the hydrogen bonds of water molecules.
• As water freezes, it takes up more oxygen from the atmosphere, causing it to have a greater buoyancy.

The pH scale is a range from:

• 1-7
• 0-14
• 1-14
• 1-20

A(n) ______ is a substance with a pH less than 7

• Acid
• Alkaline
• Base
• Buffer