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Lesson Plans
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Water Analysis Sheet Teacher Version

1. What is meant by the phrase "water is the medium of life"? (Water is a very common substance. Water makes up 80% of most living things.)

2. Polarity is caused by asymmetric/unequal electron distribution within a molecule. How does water exhibit polarity? (The water molecule has a high concentration of negative charge on the oxygen side. The two hydrogen atoms are on the opposite side of the molecule. Because oxygen has such a large affinity for electrons (it is highly electro-negative), it essentially strips the electron from each of the two hydrogen atoms. This "stripping" of electrons from the outer shell of hydrogen creates a positive charge on the hydrogen.)

3. Properties of water

  • Chemical composition: H2O

  • Bent/symmetric molecular structure caused by geometric orientation of atoms in space

  • Asymmetric molecular structure/polarity caused by unequal distribution of electrons between hydrogen and oxygen

  • Surface tension caused by hydrogen bonding

  • Capillary rise caused by hydrogen bonding

4. What geometric principle distinguishes liquid water from solid water/ice? (Hydrogen bonding causes liquid water to change its shape, whereas solid water molecules have rigid tetrahedral structures also held together by hydrogen bonding.)

5. Predict what happens as water molecules move close to each other. (As water molecules approach each other, they orient themselves (by twisting/rotating) so that they are adequately far apart. The distance between the molecules will depends largely on the temperature of the water. The molecules will never get so close that they touch because there is repulsion on the oxygen, similar to the repulsion of two magnets.)

Students may use this sheet to record various definitions. All students should have as part of their lesson notes the meaning of the following list of terms:

Bond Ionic Polarity Solute
Capillary Rise Mixture vs. Solution Polar Covalent Solvent
Non-Polar Covalent Primary Colors Surface Tension Hydrogen Bond