Unit 1 (3)

Water is known as the universal solvent, which means that many substances will dissolve in it. This property helps cells to obtain and use nutrients because about ________________ of our cells are made of water.

2/3s

It is important for us to keep our water supply clean and chemically balanced, so that it is potable and we can drink it. Having the right pH level is a part of this. What pH level should drinking water have?

7

The picture shows transpiration. Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Which of these is NOT true of environmental factors affecting the rate of transpiration?

As the relative humidity of the air surrounding the plant rises the transpiration rate rises.

Water's unique property of ______________ allows water molecules to stick together so they can be pulled upward by the force of transpiration.

Cohesion

Water has a high surface tension. Some insects can stride across the water due to the combination of their legs and the high surface tension of the water. Which property of water best explains the high surface tension?

Cohesion is a property of water that enables the high surface tension. Cohesion is the attraction of water molecules with other water molecules,

Which statement BEST explains why the specific heat of water is higher than the specific heat of most other substances?

Due to its polarity and hydrogen bonding water can absorb heat without a significant temperature change.

The images of cells seen here supports the fact that the shape of plant cells are determined by how much ________ is contained within the vacuole.

Water

This flowering plant does not wilt but stands straight up, reaching toward the sunlight, because its cells contain mostly

Water

This substance makes up the majority of your cells, and is necessary for them to carry out most of their chemical reactions. What is it?

Water

Why is water an excellent solvent for most ionic compounds and polar covalent molecules but not for non-polar compounds?

Water is a polar molecule

What property of water provides for appropriate sugar, salt, and amino acid levels to be present and carried in the blood of animals to be delivered to cells?

Water is a polar molecule that acts as a universal solvent.

Water is unusual because it expands as it freezes. Very few substances have this property. The reason liquid water is more dense then ice can be best explained by?

Water is polar and the positive and negative ends of the molecule attract each other.

The polar nature of water molecules gives water many unique properties. Which of these statements is NOT true regarding the properties of water?

Water only dissolves other nonpolar molecules.

Water is known as an universal solvent due to its ability to dissolve a wide range of chemicals. This enables water to carry valuable minerals, nutrients, and chemicals for every living thing. Which property of water best explains its ability to dissolve many chemicals and what is meant by this term?

Water's property of high polarity gives it the ability to dissolve many chemicals because hydrogen has a positive electrical charge and oxygen has a negative electrical charge.

Examine the diagram above. What property of water allows the processes of perspiration to lower mammal temperatures and transpiration to cool leaf surfaces?

Heat energy is required to break hydrogen bonds between water molecules, releasing water vapor during evaporative cooling.

Water is called the universal solvent because

It dissolves a variety of substances

What unique property of water was illustrated by this simple experiment?

Specific heat

Water has many unique properties attributed to its polarity. Which correctly pairs the water property with a correct example of the property.

Surface tension is caused by the cohesion or "stickiness" of water molecules.

If water had a LOW heat capacity, what could happen? All but one apply.

Temperature changes would require a great deal of energy input.

The main effect that water has on climate is that extreme temperatures ____________ occur in cities near large bodies of water, because water heats up and cools down very slowly.

are less likely to

The paper clip, which is denser than water, floats on the surface because of water's surface tension. Surface tension is a property of water that is the result of polar water molecules sticking together or water's property of

cohesion

When water is being transported from the roots to the leaves of a plant or tree, water vapor eventually escapes through air spaces in the plant or tree. More water travels up to replace the lost water due, in part, to the ________________ of water.

cohesive forces

Water molecules are ____________ due to _________bonding. This property helps water molecules to stick to each other and allows for the movement of water from plant roots up to plant leaves.

cohesive; hydrogen

Because water is a polar molecule, it makes an excellent solvent for atoms and compounds found within cells and tissues. Water, acting as a solvent in organisms, aids in all of the following EXCEPT

constructing cell membranes.

The Earth's oceans act as a climate moderator. Oceans do this in many ways, including ALL BUT one method listed here. That is

evenly distributing solar radiation.

Water is a very important factor for us individually, but its importance stretches further than that. For instance, because water absorbs _______ very well, the oceans help stabilize temperatures around the world.

heat

The water cycle consists of some water evaporating from the surfaces of bodies of water and going into the air. As result of air temperatures, water vapor eventually condenses and falls as rain. The rain nurtures life and the environment and eventually makes its way back into water where the cycle is repeated. Water has an unusually low vapor pressure and does not rapidly evaporate because of its

hydrogen bonding

Because water is a polar molecule, it makes an excellent solvent for polar and _________ compounds found within cells and tissues.

ionic

Fill a glass with water above the rim. It forms a domed surface. Add a paper clip and watch it float, even though the paper clip is made of a metal that is denser than water. This is due to water's surface tension. Water has several very unique properties, like surface tension, cohesion, and adhesion because water

is polar and every water molecule electrically attracts the neighboring water molecules.

The ability of water to hold more heat than land keeps the temperature on Earth

moderate

Based on this view of Earth, we would predict that

more solar radiation is absorbed by the oceans than by land masses.

Clouds act in much the same way as high humidity in Earth's atmosphere. The presence of clouds means moist, humid, atmospheric conditions. This promotes _______ heat retention, and _______ nighttime temperatures, than on a clear, dry night.

more/higher

The fact that water is a _________ molecule is important, because this allows it to dissolve many substances.

polar

Water's ___________ makes it an excellent solvent for salts, like sodium chloride, as well as other substances required by cells to carry out metabolic processes.

polarity

Approximately two-thirds of the mass of a cell is water, and the water is important to maintain the cell's integrity. What would happen to a plant cell during a period of severe drought?

the cell would eventually shrink causing the plant to wilt

During the winter months, water on the surface of a pond will typically freeze and this ice acts as an insulator for the water beneath it. As a result, aquatic life is able to survive during the cold winter. The reason that this water expands upon freezing is due to

the hydrogen bonding that creates its hexagonal shape.

Water can dissolve more susbstances than any other substance. In biology, this is important because water can transport many compounds around the body. In science water is called

the universal solvent

About 2 3 of the mass of this cell is

water

The cell membrane helps to control what enters and leaves a cell. Which of these substances, which accounts for about two-thirds of a cell's mass, is constantly moving in and out of the cell?

water

Organisms living in the oceans are provided with a relatively constant environmental temperature. In order for plants and animals to make the move to land, a high cellular _________ was critical to help maintain a relatively constant internal temperature.

water concentration

During the winter, many creatures are able to drastically decrease their body temperatures and energy use and enter a reduced state of metabolism. Even though environmental temperatures may be well below freezing, these animals survive. This is due in part to their hibernation but most importantly to the fact that

water has a high specific heat capacity.