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Cards In This Set
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With the use of a diagram or diagrams, explain why water molecules are:
Polar Capable of hydrogen bonding with four neighboring water molecules. |
Picture:
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List four characteristics of water that are emergent properties resulting from hydrogen bonding:
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Cohesive behavior, ability to moderate temperature, expansion upon freezing, versatility as a solvent.
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Define Cohesion:
Define Adhesion: Explain how waters cohesion and adhesion contribute to the movement of water from the roots to the leaves of a tree |
Cohesion: Water molecules interact with each other
Adhesion: Water molecules can interact with other substances Explain: Cohesion due to hydrogen bonds between water molecules helps hold together the column of water within the cells. (Water from the roots reaches the leaves) Adhesion: of the water to cell walls by hydrogen bonds helps resist the downward pull of gravity |
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Distinguish between heat and temperature, using examples to clarity your definitions.
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Heat: is a form of energy (total kinetic energy)
Temperature: is a measure of heat intensity (average kinetic energy) Example: When water is heated in a coffeemaker, the average speed of the molecules increases, and the thermometer records this as a rise in timperature of the liquid, the amound of heat also increases, however that although the pot of coffee has a much higher temperature than, say, the water in a swimming pool, the swimming pool contains more heat because of its much greater volume. |
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Explain the following observations in reference to the properties of water:
1)Coastal areas have milder climates than adjacent inland areas |
1) Waters high specific heat to life on earth: A large body of water can absorb and store a huge amount of heat from the sun in the daytime and during summer while warming up only a few degrees. At night and during winter, the gradually cooling water can warm the air.
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2) Ocean temperatures fluctuate much less than air temperatures on land.
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2) The high specific heat of water also tends to stabilize ocean temps
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3) Insects like water striders can walk on the surface of a pond without breaking the surface.
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3) The high surface tension of water, resulting from the collective strength of its hydrogen bonds
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4) Ice floats on water.
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4) Ice is less dense than liquid water
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4) Ice floats on water.
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4) Ice is less dense than liquid water
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5) Evaporative cooling
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5) occurs because the "hottest" molecules, those with the greatest kinetic energy, are most likely to leave as a gas
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Distinguish among a
1) Solute 2) Solvent 3) Solution |
1) Solute: The substance that is dissolved
2) Solvent: The dissolving agent 3) Solution: A liquid that is completely homogenous mixture of two or more substances |
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Distinguish between hydrophobic, and hydrophilic substances
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Hydrophobic: Substances that seem to repel water
Hydrophilic: Any substance that has an affinity (the degree to which a substance tends to combine with another) for water |
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Explain how you would make up a liter of one molar (1 M) solution of salt (NaCl). How would you weigh out? What percent (w/v) of NaCl would this correspond to?
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A 1 molar solution is a solution in which 1 mole of a compound is dissolved in a total volume of 1 litre.
For example: The molecular weight of sodium chloride (NaCl) is 58.44, so one gram molecular weight (= 1 mole) is 58.44g. If you dissolve 58.44g of NaCl in a final volume of 1 litre, you have made a 1M NaCl solution. To make a 0.1M NaCl solution, you could weigh 5.844g of NaCl and dissolve it in 1 litre of water; OR 0.5844g of NaCl in 100mL of water (see animation below); OR make a 1:10 dilution of a 1M sample. |
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Name the products of the dissociation of water and give their concentrations in pure water.
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Hydronium ion + Hydroxide ion
(H+)=(OH-)= 10(to the) -7 M |
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Define
Acid: Base: PH: |
Acid: is a substance that increases the hydrogen ion concentration of a solution.
Base: is a substance that reduces the hydrogen ion concentration of a solution PH: of a solution is defined as a negative logarithm (base 10) of the hydrogen ion concentration: |
