Topic 2.2:  Water

Essential Idea:  Water is the medium of life.

At SHS, Topic 2.2 is taught in the following class unit(s):

• Water (unit 9)

Statements & Objectives:

2.2.U1  Water molecules are polar and hydrogen bonds form between them.

• Describe the structure of an atom (in terms of protons, neutrons and electrons).
• Contrast ion with atom.
• Define anion and cation.
• Contrast covalent, ionic and hydrogen bonds. 
• Write the molecular formula for water and draw the atomic structure of the molecule.
• Describe the cause and effect of the polar nature of water.
• Describe where and how water is able to form hydrogen bonds.​

2.2.U2  Hydrogen bonding and dipolarity explain the cohesive, adhesive, thermal and solvent properties of water.

• Contrast adhesion with cohesion.
• Outline an example of the cohesive property of water being of benefit to life.
• Outline an example of the adhesive property of water being of benefit to life.
• Explain three thermal properties of water that are useful to living organisms.
• Outline a benefit to life of water's high specific heat capacity.
• Outline a benefit to life of water's high latent heat of vaporization.
• Outline a benefit to life of water's high boiling point.
• Explain why is water such a good solvent.
• List the types of molecules that water will dissolve.​

2.2.U3  Substances can be hydrophilic or hydrophobic.

• State that polar and ionic molecules are hydrophilic.
• State that non-polar, non-ionic molecules are hydrophobic.
• Given a diagram of a molecular structure, determine if the molecule is hydrophilic or hydrophobic.

2.2.A1  Comparison of the thermal properties of water with those of methane.

• Compare the physical properties of methane and water.
• Explain why water and methane have different thermal properties based on their molecular structures.

2.2.A2  Use of water as a coolant in sweat.

• Explain sweating as a mechanism to cool the body.

2.2.A3  Modes of transport of glucose, amino acids, cholesterol, fats. oxygen, and sodium in blood in relations to their solubility in water.

• State if the following molecules are hydrophobic or hydrophilic:  glucose, amino acids, cholesterol, fats, oxygen, and sodium chloride.
• Outline the mechanism of transport in the blood of the following molecules:  glucose, amino acids, cholesterol, fats, oxygen, and sodium chloride.

2.2.NOS  Use of theories to explain natural phenomena- the theory that hydrogen bonds form between water molecules explain the properties of water.

• State why scientists cannot prove without a doubt that hydrogen bonds exist between water molecules.

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