1. Water and its properties

2. WATER IS POLAR In each bond, oxygen is electronegative, H is electropositive Accounts for water’s being an excellent solvent

3. Hydrogen bonds The magic of water! Accounts for: –Surface tension. –High boiling point –High Molar Heat of Vaporization –High Molar Heat of fusion –Solid less dense than water (hydrogen bonds longer in ice than in liquid water)

4. Ice Floats! Less dense than liquid water Due to longer and more flexible hydrogen bonds in solid, causing empty space Allow for life in ponds and lakes to survive winter—otherwise ponds and lakes may freeze solid Maximum density occurs at 3.98 C—water molecules most tightly packed then

5. Math With Molar Heat of Fusion and Vaporization Water’s Molar Heat of Fusion: –6.008 kJ/mol –Molar Heat of Vaporization: 40.79 kJ/mol

6. How much heat energy is released when 506 grams of water freezes? (Molar heat of fusion is 6.008 kJ/mol)

7. Another one…. How many grams of steam releases 4.97x10 5 kJ upon condensation (Molar heat of vaporization is 40.79 kJ/mol)?

8. Yet another one… How much heat energy is absorbed when 55.0 g of ice melts at STP?

9. Last One… How many grams of water is vaporized by 0.545 kJ of heat?