Ocea 10
Chapter 5: Water and Seawater
Review Questions (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 17)
2. Describe what condition exists in water molecules to make them dipolar. The bent geometry of water molecule gives a slight overall negative charge to the side of the oxygen atom and a slight overall positive charge to the side of the hydrogen atom. This slight separation of charge gives the entire molecule an electrical polarity so water molecules are dipolar.
4. How does hydrogen bonding produce the surface tension phenomenon of water? Surface tension results from the formation of hydrogen bonds between the outermost layer of water molecules and the underlying molecules. Water’s ability to form hydrogen bonds causes it to have highest surface tension of any liquid except the element mercury.
5. Discuss how the dipolar nature of the water molecule makes it such an effective solvent of ionic compounds. Water molecules stick not only to other water molecules, but also to other polar chemical compounds. In doing so, water molecules can reduce the attraction between ions of opposite charges by as much as 80 times. Because water molecules interact with other water molecules and other polar molecules, water is able to dissolve nearly anything. Given enough time, water can dissolve more substances and in greater quantity than any other known substances. This is why water is called “the universal solvent.”
6. Why are the freezing and boiling points of water higher than would be expected for a compound of its molecular makeup? Water melts and boils at the relatively high temperature of 0 degree Celsius (32 degrees Fahrenheit) and 100 degrees Celsius (212 degrees Fahrenheit), respectively, because additional heat energy is required to overcome its hydrogen bonds and van der Waals forces. Thus, if not for the unusual geometry and resulting polarity of the water molecule, all water on Earth would be boiled away and life as we know it would not exist.
7. How does the
Review Questions (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 17)
2. Describe what condition exists in water molecules to make them dipolar. The bent geometry of water molecule gives a slight overall negative charge to the side of the oxygen atom and a slight overall positive charge to the side of the hydrogen atom. This slight separation of charge gives the entire molecule an electrical polarity so water molecules are dipolar.
4. How does hydrogen bonding produce the surface tension phenomenon of water? Surface tension results from the formation of hydrogen bonds between the outermost layer of water molecules and the underlying molecules. Water’s ability to form hydrogen bonds causes it to have highest surface tension of any liquid except the element mercury.
5. Discuss how the dipolar nature of the water molecule makes it such an effective solvent of ionic compounds. Water molecules stick not only to other water molecules, but also to other polar chemical compounds. In doing so, water molecules can reduce the attraction between ions of opposite charges by as much as 80 times. Because water molecules interact with other water molecules and other polar molecules, water is able to dissolve nearly anything. Given enough time, water can dissolve more substances and in greater quantity than any other known substances. This is why water is called “the universal solvent.”
6. Why are the freezing and boiling points of water higher than would be expected for a compound of its molecular makeup? Water melts and boils at the relatively high temperature of 0 degree Celsius (32 degrees Fahrenheit) and 100 degrees Celsius (212 degrees Fahrenheit), respectively, because additional heat energy is required to overcome its hydrogen bonds and van der Waals forces. Thus, if not for the unusual geometry and resulting polarity of the water molecule, all water on Earth would be boiled away and life as we know it would not exist.
7. How does the