Question

1. What are the atoms that make up one water molecule?

1. 1 carbon and 2 oxygen
2. 1carbon and 2 hydrogen
3. 1 oxygen and 2 hydrogen
4. 1 oxygen and 2 carbon

2. Water is polar because the oxygen molecule is slightly positive.

True                                               False

3. Why is the meniscus in a graduated cylinder of water concave?

1. Adhesion between water and glass is stronger than water's cohesion
2. Water's cohesion is much stronger than the adhesion between water and glass
3. Water's cohesion is as strong as adhesion between water molecules and glass
4. Water molecules are attracted to each other but repelled by the glass

4. When lakes partially freeze in the winter, aquatic animals like fish are able to survive in the oxygenated water at the lake bottom. (highlight your answer) What features allow water to remain liquid at the bottom of the lake? Select all that apply.

1. When water in a lake freezes, the ice floats on the surface of the water
2. Ice is much denser than liquid water, so it forms at the bottom of the pond first
3. Liquid water is denser (heavier) than ice because the molecules are more tightly packed together
4. In frozen water (ice), water molecules have a rigid hydrogen bonding pattern that keeps them spread further apart than in liquid water

5. Why does your backyard pool stay warmer even after the temperature of the air in the evening starts to drop?
   1. Water has a high specific heat and holds heat longer than the dry ambient air.
   2. When the sun goes down, the wind starts to blows.
   3. The air is heated by the sun and the water is heated by the ground.

Answer 1

1. C)  1 oxygen and 2 hydrogen

Water is made up of 2 hydrogen and 1 oxygen that are bound together by co valent bonds.

2. True

In the co valent bond , oxygen is slightly positive and attracted towards negative than the hydrogen atoms thus it becomes polar

3. A) cohesion between water and glass is stronger than water's cohesion

Water molecule cohension in glass is less and adhesion between glass and water is stronger that results in concave structure

4.

1. When water in a lake freezes, the ice floats on the surface of the water
2. Ice is much denser than liquid water, so it forms at the bottom of the pond of water first