question 1

Bonding and Charges
Oxygen is one of the most
of all the elements, attracting shared electrons much more strongly than hydrogen does.

question 2

Because electrons have a negative charge, the unequal sharing of electrons in water causes the oxygen atom to have a partial charge (indicated by the Greek letter δ with a minus sign, δ-,or "delta minus") and each hydrogen atom to have a partial charge (δ +, or "delta plus").

question 3

A bond forms when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom. In living cells, the electronegative partners are usually oxygen or atoms.

question 4

Because oxygen is electronegative than hydrogen, the electrons of the covalent bonds spend more time closer to than to ; in other words, they are covalent bonds.

question 5



The black box in the above image should contain the word
.

In some cases, two atoms are so unequal in their attraction for
electrons that the more electronegative atom strips an electron completely away from its partner.

question 6

Water
Water's Life-Supporting Properties:




Hint: Soaked corks float turgidly.

question 7

Most cells are surrounded by water, and cells themselves are about -95% water.

question 8

The anomalous properties of water arise from attractions between its polar molecules: The slightly hydrogen of one molecule is attracted to the slightly oxygen of a nearby molecule.

question 9

When water is in its liquid form, its hydrogen bonds are very fragile, each about 1/ as strong as a covalent bond. The hydrogen bonds form, break, and reform with great frequency. Each lasts only a few trillionths of a , but the molecules are constantly forming new hydrogen bonds with a succession of partners.

question 10

Collectively, the hydrogen bonds hold the substance together, a phenomenon called . Cohesion due to hydrogen bonds between water molecules helps hold together the column of water within the cells.

question 11

is the clinging of one substance to another.

question 12

Water has a greater than most other liquids. At the interface between water and air is an ordered arrangement of water molecules, hydrogen-bonded to one another and to the water below. This makes the water behave as though coated with an invisible film. You can observe the surface tension of water by slightly overfilling a drinking glass; the water will stand above the rim. Also, some animals can stand, walk, or run on water without breaking the surface.

question 13

Water air temperature by heat from air that is warmer and the stored heat to air that is cooler.

question 14

For a given body of matter, the amount of heat is a measure of the matter's total due to motion of its molecules; thus, heat depends in part on the matter's .

question 15

Although the pot of coffee has a much higher than the water in a swimming pool, the swimming pool contains more because of its much greater volume.

question 16

The Celsius scale is used to indicate ; a convenient unit of is the calorie.

question 17

The of a substance is defined as the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1C.

question 18

Because of the high heat of water relative to other materials, water will change its temperature less when it absorbs or loses a given amount of heat.

question 19

What is the relevance of water's high specific heat to life on Earth? A large body of water can and a huge amount of from the sun in the daytime and during summer while warming up only a few degrees. And at night and during winter, the gradually cooling water can warm the air.

question 20

is the quantity of heat a liquid must absorb for 1 g of it to be converted from the liquid to the gaseous state. For the same reason that water has a high specific heat, it also has a high heat of vaporization relative to most other liquids.

question 21

In ice, each molecule is -bonded to (Three? Four? Five?) neighbors in a three-dimensional . Because the crystal is spacious, ice has molecules than an equal volume of liquid water. In other words, ice is less than liquid water.

question 22

When a deep body of water cools, the ice insulates the liquid water below, preventing it from and allowing life to exist under the frozen surface.

question 23

A liquid that is a completely homogeneous mixture of two or more substances is called a . The dissolving agent of a solution is the , and the substance that is dissolved is the . An solution is one in which water is the solvent.

question 24



Water is a very versatile solvent, a quality we can trace to the
of the water molecule.

question 25

Occasionally, a hydrogen atom participating in a hydrogen bond between two water molecules shifts from one molecule to the other. When this happens, the hydrogen atom leaves its behind, and what is actually transferred is a hydrogen ion (H+), a single proton with a charge of 1+. The water molecule that lost a proton is now a ion (OH-), which has a charge of 1-. The proton binds to the other water molecule, making that molecule a ion (H30+).

question 26

When dissolve in water, they donate additional H+ to the solution. An is a substance that increases the hydrogen ion concentration of a solution.

question 27

A substance that reduces the hydrogen ion concentration of a solution is called a .



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