Properties of Water: The Water Molecule

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Structure of Water

Cohesion and Adhesion

Properties of Water:

Surface Tension Demonstrated by a Water Strider

The structure of ice

ICE

WATER

High Specific Heat

Specific Heats of Some Common Substances[J/(g x oC)]

Water 4.18Grain alcohol 2.4

Ice 2.1Wood 1.8Steam 1.7

Chloroform 0.96Aluminum 0.90

Glass 0.50Iron 0.46

Copper 0.39Silver 0.24

Mercury 0.14

Properties of Water:

Water is the Solvent of Life

Solubility:

The amount of solute that can be dissolved into a given amount of solvent at a given temperature.

Rock Candy

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Dissolved Gases

Thermal Pollution

• Thermal PollutionThis 1988 thermal image of the Hudson River highlights temperature changes caused by discharge of 2.5 billion gallons of water each day from the Indian Point power plant. The plant sits in the upper right of the photo ﾑ hot water in the discharge canal is visible in yellow and red, spreading and cooling across the entire width of the river. Two additional outflows from the Lovett coal-fired power plant are also clearly visible against the natural temperature of the water, in green and blue.

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Lake Nyos 1986

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De-gassing Lake Nyos

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Molarity

• What is the molarity of 30.0 liter solution with 10.0 grams of LiCl dissolved into it?

Molarity

• How many grams of barium hydroxide are needed to make 500. ml of a 0.80 M solution?

Molarity

• What is the concentration of sulfate ions in a 2.0 M lead (IV) sulfate solution?

• What is the concentration (M) of sodium ions in 100. ml of a 0.50 M solution of sodium sulfate?

Dilutions

• How many ml of a 12M stock solution of HCl are needed to make 100.0 ml of a 2.5M solution?

• Describe the procedure for diluting a 6.0M NaCl solution to 50.0ml of a 0.50 M solution.

Mole Fraction

17 grams of NaOH is dissolved into 55 grams of water.

• What is the mole fraction of NaOH?

• What is the mole fraction of water?

Colligative Properties

• Vapor Pressure Lowering

• Freezing Point Depression

• Boiling Point Elevation

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Colligative Properties

• What is the f.p. of a sucrose solution dissolved in water if the conc. is 2.3 molal?

(Kf water = 1.86 oC/m)

• What is the f.p. of a solution if it contains 107 g of KCl dissolved in 187 grams of water? (Kf water = 1.86 oC/m)

Colligative Properties

• If 25.0 grams of Ammonium phosphate are dissolved into 2.6 moles of water, what would the freezing point be? (Kf water = 1.86 oC/m)

• How many milliliters of ethanol (C2H6O) must a researcher add to 550 grams of water so that the solution will have a boiling point of 104.5oC? (Kbp water = 0.52 oC/m) (density ethanol = 0.79 g/ml)

Colligative Properties

• How many grams of gasoline solvent are in a 1.6 M solution containing 34.50 grams of solid 1,4-dichlorobenzene (C6H4Cl2). (density of the solution is = 0.69 g/ml)?