1. Properties of Water SC.912.L.18.12

2. Polar bears spend most of their lives roaming the Arctic on large sheets of floating ice, using them as platforms from which they hunt seals when the seals make holes in the ice to breathe. Rising average temperatures are causing these ice sheets to diminish in size, putting stress on the polar bears' way of life. Ice in a glass of water floats just like ice sheets in the arctic. What characteristic of frozen water makes it float instead of sink? A. The water traps air bubbles as it freezes, which makes it float. B. Some of the water evaporates as it freezes, making the ice lighter. C. The molecules in ice are less densely packed than in liquid water. D. The ice molecules become polarized so they migrate upward in the glass. C. The molecules in ice are less densely packed than in liquid water.

3. Citrus trees can be damaged or even killed if temperatures stay below freezing long enough. On very cold winter nights in Florida, the citrus growers turn on the irrigation systems in the groves to spray water on the trees, which forms a coat of ice on them. There are several reasons why this is helpful in protecting the trees. Which of the following is one of these reasons? A. Water releases heat as it freezes. B. Ice protects the trees from wind chill. C. Water keeps the trees from drying out. D. Ice freezes the fruit so it won't rot. A. Water releases heat as it freezes.

4. Capillary action in plants allows water to be transported through narrow tubes from the plants' roots to their leaves, where it is used in photosynthesis. This is possible because of the way water molecules interact with each other and other materials. Water molecules are most like which of the following in the way they interact with each other? A. ants B. magnets C. balls D. marshmallows B. magnets.

5. In places that get very little rainfall, such as the desert in Arizona, daytime temperatures can get very high and nighttime temperatures can get very low, often dropping dramatically as soon as the Sun sets. How would temperatures be different if there was more water there? A. not as hot in the day and warmer at night B. cooler in the day but still cold at night C. very hot in the day and even colder at night D. warmer in the day and warmer at night A. not as hot in the day and warmer at night

6. Sometimes salt is used on roads to keep them free of ice. It mixes with water and can flow into nearby lakes, where the salty water sinks to the bottom, reducing the natural mixing of the lake water and resulting in depleted oxygen levels for aquatic life. When the salt first mixes with water, its crystals come apart and are no longer visible. Why does salt react this way in water? A. The salt molecules form covalent bonds with the water molecules and lose their crystal form. B. The polarized water molecules make the salt crystals become polarized as well. C. The heat in the water makes the salt crystals melt so they can't be seen. D. The salt molecules are ionically bonded and the polarized water molecules pull them apart. D. The salt molecules are ionically bonded and the polarized water molecules pull them apart.

7. Plants are able to get water to come into their roots even if the water in the soil is slightly downhill from the root. What property of water molecules makes it possible for this to happen? A. The charged molecules in the soil push the polarized water molecules away and force them into the roots. B. The polarized water molecules stick to each other and to the water molecules already in the roots and soil. C. Water molecules only have three atoms, and they are tiny enough that gravity won't affect them. D. The water molecules begin to evaporate as the soil warms, and they float uphill and into the roots. B. The polarized water molecules stick to each other and to the water molecules already in the roots and soil

8. Water molecules evaporate from lakes and rivers when the Sun gives them enough energy to be able to escape the hold of the other water molecules around them. What makes these water molecules eventually form into clouds and drop again as rain or snow, instead of continuing to float around? A. They are heavier than the air around them, so eventually they will have to fall down. B. Each water molecule expands when heated, making it rise, and the molecules fall as they lose heat. C. They are polarized, so they will stick to each other as they lose heat energy and slow down. D. Once the water molecules hit a cloud, they give up their heat to the cloud and fall down. C. They are polarized, so they will stick to each other as they lose heat energy and slow down.

9. Some insects can walk on the surface of water. Their feet push against the surface of the water and the water surface bends down under their weight but does not break. What do the individual water molecules do that makes this possible? A. The molecules push on the ones below them and only sink a little. B. The molecules hang on to each other because they are polarized. C. The polarized water molecules are drawn toward the insect's feet. D. The surface water molecules push on the insect as they evaporate. B. The molecules hang on to each other because they are polarized.

10. During the heat of the summer it is refreshing to cool down in the ocean at the beach because water can absorb more heat than land, the water does not increase in temperature as fast because it has a high a.Polarity b.Heat capacity c.Surface tension d.Surface area b. Heat capacity

11. 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. C. Water exhibits cohesive behavior.

12. OUT OF 10 QUESTIONS 1/10 = 10% 2/10 = 20% 3/10 = 30% 4/10 = 40% 5/10 = 50% 5/10 = 50% 6/10 = 60% 6/10 = 60% 7/10 = 70% 7/10 = 70% 8/10 = 80% 9/10 = 90% 10/10 = 100%