Chapter 2

Which of the follow statements about acids, bases, and pH is true?

A solution with a lower pH is more acidic than one with a higher pH.

Indivisible, the smallest unit of matter

Atom

determines which element an atom is

Atomic number

Describe how increased carbon dioxide emissions leads to acid rain, and how acid rain is harmful to oceanic life

Carbon dioxide in the atmosphere gets converted into carbonic acid, decreasing the pH of rain from 5.6 to 5.2. When this rain falls into the ocean (or other bodies of water) it can acidify the water in which it falls, killing off sessile organisms (coral, plants, etc.) and causing other to leave the area. This creates oceanic "dead zones".

A substance that cannont be broken down to other substance by ordinary chemical means

Element

Which characteristic of water allows insects to walk on water?

Hydrogen bonding between water molecules gives water a high surface tension that provides enough resistance for light insects to walk across.

Which of the following statements about chemical bonds in correct?

In a chemical reaction the products are the end materials resulting from the conversion of the starting materials called reactants.

Which statement about chemical bonding is correct?

In covalent bonds electrons are shared between atoms.

have the same number of protons and electrons, thus they have the same atomic number and the same chemical reactions. But have different numbers of neutrons

Isotopes

Which of the following statements about water is NOT true?

Like most substances, frozen water (ice) is denser than its liquid form.

the sum of the number of protons and neutrons in its nucleus

Mass number

Control Center

Nucleus

chemical components that naturally occur in soil, plant, and wildlife in minute concentrations.

Trace elements

Which of the following statements about trace elements is correct?

Trace elements are those elements that are required by living things in small amounts. Trace elements are often common additives to food and water. Calcium, phosphorus, and magnesium are trace elements required by humans

Which statement about hydrogen bonds is correct?

a. Hydrogen bonds occur through the attraction of two different molecules with opposite charges. b. The nature of hydrogen bonding between water molecules explains why water molecules spread out at cooler temperatures making ice less dense than liquid water. c. Water can form hydrogen bonds because of its bent shape, which is the result of the polar covalent bonds between oxygen and hydrogen atoms.

a compound that donates hydrogen ions to solution is called an

acid

refers to rain, snow, or fog with a pH lower than 5.2

acid precipitation

clinging of one substance to another

adhesion

If frozen water did not float:

aquatic life could not exist the water at the bottom of the ocean would freeze causing ocean levels to rise and flood the majority of land of Earth there would be no iced tea

is one in which water is the solvent

aqueous solution

Substances that dissolve water:

are hydrophilic , b. are able to break the cohesive forces of the water molecules allowing the water molecules to form a shell around them

atomic weight

atomic mass

a compound that accepts hydrogen ions and removes them from solution

base

substance that minimize changes in pH

buffers

the breaking and making of chemical bonds

chemical reactions

to stick together

cohesion

A substance consisting of two or more different elements combined in a fixed ratio.

compound

the atoms are bound by the shared electrons

covalent bond

Single negative electrical charge

electron

electrons move around the nucleus only at certain energy levels

electron shells

a measure of the tendency of an atom to attract a bonding pair of electrons.

electronegativity

occurs when the molecules with the greatest energy leaves

evaporative cooling

the amount of energy associated with the movement of atoms and molecules in a body of matter

heat

Which characteristic of water allows sweating to cool down your body?

high heat capacity

Water molecules adhere to surfaces and stick to each other via:

hydrogen bonds

an electrical charge resulting from a gain or loss of one or more electrons.

ion

In what type of bond does one atom simply "give" an electron to another atom?

ionic bond

Hydrogen bonding is responsible for which attribute of water?

its ability to dissolve many substances,its ability to form a crystalline solid that is less dense than its liquid form, its cohesive and adhesive properties, as well as capillary action

two or more atoms held together by covalent bonds

molecule

No charge

neutron

shared equally between atoms

nonpolar covalent bonds

CO2 dissolving in seawater lowers ocean pH

ocean acidification

describe how acidic or base a solution is

pH scale

The hydrogen and oxygen atoms within a water molecule a connected by a(n):

polar covalent bond

unequal sharing of electrons produces a

polar covalent bond

an unequal distribution of charges.

polar molecule

material resulting from the chemical reaction

product

Single positive electrical charge

proton

staring materials

reactants

substance that is dissolved is a

solute

is a liquid consisting of uniform mixture of two or more substances

solution

dissolving agent

solvent

a measure of how difficult it is stretch or break the surface of a liquid

surface tension

measure the intensity of heat

temperature

Which component(s) of an atom participate in chemical bonding?

the outmost electrons