Properties of Water

A water molecule has the chemical formula H2O. This means that the water molecule is made up of

• Two hydrogen atoms and one oxygen atom

• Two oxygen atoms and one hydrogen atom

• Two hydrogen atoms and two oxygen atoms

• Two molecules of water

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The atoms in a water molecule are held together by covalent bonds. This means that the bonded atoms

• Lose protons

• Lose electrons

• Share electrons

• Switch neutrons

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The water molecule is a polar molecule. A water molecule is polar because

• The electrons are shared equally

• Oxygen has a stronger attraction for electrons than hydrogen

• It is very cold

• Hydrogen atoms have a stronger attraction for electrons than oxygen

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The water molecule is

• Slightly negative near the hydrogen atoms and slightly positive near the oxygen atom

• Slightly positive in all areas of the molecule

• Slightly negative near the oxygen atom and slightly positive near the hydrogen atoms

• The same charge in all areas of the molecule

Water molecules are attracted to each other because

• They are all positively charged

• Each water molecule has the same number of protons as electrons

• The positive area of one water molecule is attracted to the negative area of another

• All water molecules are neutral

A paper clip can stay on the surface of a sample of water because of water’s strong surface tension. Water’s surface tension is mostly a result of

• Water’s temperature

• The motion of water molecules

• The attraction of water molecules

• The impurities in the water

Water is able to dissolve sodium chloride because

• The polar areas of water molecules attract the oppositely charged ions of sodium chloride

• The shape of the water molecules pushes the sodium and chloride ions apart

• The oxygen in the water molecules reacts with the sodium and chloride ions

• Water molecules and sodium chloride are covalently bonded

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Polar liquids, like water, dissolve other liquids which are polar or somewhat polar

• True

• False

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

• Cohesion

• Surface Tension

• Capillary Action

Ice freezes at the top of a pond and protects the aquatic life underneath. What property of water is KEY in this situation?

• Cohesion

• Adhesion

• Ice is less dense than liquid water

• The top of a pond is always the coldest part