Water Properties

1. Water is essential for life. Its special properties make water the single most important molecule in plant life. Which of the following properties of water enables it to move from the roots to the leaves of plants?

• A. Water expands as it freezes.

• B. Water is an excellent solvent.

• C. Water exhibits cohesive behavior.

• D. Water is able to moderate temperatures.

2. Most of water's unique features (such as its great ability to dissolve other substances, its high boiling point, and its great surface tension) result from the fact that

• A. hydrogen is the only element without any neutrons

• B. oxygen attracts electrons more than hydrogen does

• C. hydrogen attract electrons more than oxygen

• D. hydrogen and oxygen share electrons equally

3. Temperatures around large bodies of water tend to be more moderate than temperatures inland. What properties of water accounts for this?

• A. Water has low salinity.

• B. Water has a higher density than solvents.

• C. Water has the ability to absorb, store, and release large amounts of thermal energy.

• D. Water has polar properties that cause cohesion among individual water molecules.

Tags

NGSS.HS-ESS2-5

4. All living things need to transport molecules from one place to another in order to carry out necessary life functions. Living things often transport these molecules by dissolving or dissociating them in water and then moving the resulting solutions from place to place. What characteristic must a molecule have for it to form a solution in water?

• A. It must be at least as small as the polar water molecules.

• B. It must be nonpolar to be able to react with the polar molecules.

• C. It must be at least slightly polar to be able to react with the polar water molecules.

• D. It must be covalently bonded in order to form new bonds with the polar molecules.

The water strider in the image can walk on water because water has a high surface tension. Which property of water molecules gives water its high surface tension?

• A. Water molecules pack together tightly.

• B. Water molecules attract other water molecules.

• C. Water molecules are farther apart in the solid phase.

• D. Water molecules attract molecules of adjacent surfaces.

6. When water in a lake freezes, the ice that forms floats on top of any water that is still liquid. Why does the ice float?

• A. Ice is less dense than liquid water, so it floats

• B. Air bubbles trapped in the ice cause the ice to float

• C. Ice crystals are polar, and they float on top of non-polar water

• D. The ice forms at the top of the water, so it stays there and floats

7. When salt is mixed with water and stirred, the salt will dissolve, forming a solution. When sand is mixed with water, the sand will not dissolve. Why will salt form a solution with water, but sand will not?

• A. Sand is much harder than salt and so it will not form a solution with water

• B. Salt is pulled apart into two ions by the polar water molecules, and sand is not

• C. Salt consists of only 2 atoms and is small enough to dissolve, while sand is too large

• D. Sand forms complex crystals which dissolve much more slowly than non-crystalline salt

8. When the oxygen atom in one water molecule is close to a hydrogen atom in another water molecule, what is most likely to happen?

• A. The water molecules will draw toward each other

• B. The two water molecules will form a larger molecule

• C. The like charges of the water molecules will repel each other

• D. The two water molecules will gain energy and vaorize, becoming water vapor

Tags

NGSS.MS-PS2-5

9. In Florida, daytime and nighttime temperatures usually only differ 5 to 10 grade centigrade, while temperatures in the desert often differ by as much as 40 grade centigrade. What role does water play in keeping temperatures in Florida from fluctuating dramatically?

• A. Bodies of water store heat during the day and release it at night

• B. Humid air releases heat as it rises, keeping temperatures constant

• C. Evening rain brings heat from the upper atmosphere back to Earth

• Water cools the land around it so that it never gets as hot as a desert

Tags

NGSS.MS-ESS2-6

10. When trees pull water in through their roots, they must then move the water up to their leaves in order to carry out photosynthesis. Since the water molecules cling to each other and to the inner surface of the xylem, the water can pull itself up through the tree by capillary action. Which property of water molecules allows them to cling together?

• A. Water molecules are polar molecules

• B. Water molecules are small molecules

• C. Water molecules have an odd number of atoms

• D. Water molecules have covalent bonds between atoms

Tags

NGSS.MS-ESS2-4