Chapter 2: Atoms, Molecules, And Water

Front 1

Define Matter

Back 1

Anything that has mass and takes up space

Front 2

Define Atom

Back 2

The smallest functional unit of matter that forms all chemical substances and cannot be further broken down into other substances by ordinary chemical or physical means

Front 3

Define Organic Chemistry

Back 3

The study of carbon-containing molecules

Front 4

Define Solid, Liquid, and Gas

Back 4

Solid: Firm and stable, does not take shape of container

Liquid: Fluid in movement, takes shape of container

Gas: Air-like substance, fills up container

Front 5

Define Molecules

Back 5

Two or more atoms that are connected by chemical bonds

Front 6

Define element

Back 6

A substance of specific types of atoms that cannot be further broken down by ordinary chemical or physical means

Front 7

Define Proton

Back 7

A positively charged particle found in the nucleus of an atom. The number of protons in an atom is called the atomic number and defines each type of element

Front 8

Define Neutron

Back 8

A neutral particle found in the center of an atom

Front 9

Define Electron

Back 9

A negatively charged particle found in orbitals around an atomic nucleus

Front 10

Define Neutral Atom

Back 10

An atom in which the number of electrons that surround the nucleus is equal to the number of protons in the nucleus, so that there is no net electric charge.

Front 11

Define Ion

Back 11

An atom or molecule that gains or loses one or more electrons an acquires a net electric charge

Front 12

Define Isotope

Back 12

An element that exists in multiple forms that differ in the number of neutrons they contain

Front 13

Define Radioisotopes

Back 13

An isotope found in nature that is inherently unstable and usually does not exist for long periods of time. Such isotopes decay and emit energy in the form of radiation

Front 14

Define Orbitals

Back 14

The region surrounding the nucleus of an atom where the probability is high of finding a particular electron

Front 15

Define Valence Electrons

Back 15

An electron in the outer shell of an atom that is available to combine with other atoms. Such electrons allow atoms to form chemical bonds with each other

Front 16

Define Energy Shells

Back 16

In an atom, an energy level of electrons occupied by one or more orbitals; each energy level is a characteristic distance from the nucleus, with outer shells having more energy than inner shells

Front 17

Define Atomic Number

Back 17

The number of protons in an atom

Front 18

Define Atomic Mass

Back 18

An atom's mass relative to the mass of other atoms

Front 19

Define Periodic Table

Back 19

A table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns.

Front 20

Define Mole

Back 20

The amount of any substance that contains the same number of particles as there are atoms in exactly 12g of carbon

Front 21

Define Molecular Formula

Back 21

A representation of a molecule that consists of the chemical symbols for all of the atoms present and subscripts that indicate how many of those atoms are present

Front 22

Define Compound

Back 22

A molecule composed of two or more different elements

Front 23

Define Covalent Bond

Back 23

A chemical bond in which two atoms share a pair of electrons

Front 24

Define Octet Rule

Back 24

The phenomenon that some atoms are stable when their outer shell is full with eight electrons

Front 25

Define Single Bond

Back 25

A chemical bond in which one pair of electrons is shared between two atoms

Front 26

Define Double Bond

Back 26

A1 chemical bond in which two pairs of electrons are shared between two atoms

Front 27

Define electronegativity

Back 27

A measure of an atom's ability to attract electrons to its outer shell from another atom

Front 28

Define Polar Covalent Bond

Back 28

A covalent bond between two atoms that have different electronegativities; the shared electrons are closer to the atom of the higher electronegativity than the atom of the lower electronegativity. The distribution of electrons around the atoms creates a polarity, or difference in electric charge, across the molecule

Front 29

Define Nonpolar Covalent Bond

Back 29

A strong bond formed between two atoms of similar electronegativities in which electrons are shared between the atoms

Front 30

Define Polar Molecules

Back 30

A molecule containing significant numbers of polar bonds

Front 31

Define Nonpolar Molecules

Back 31

A molecule composed predominantely of nonpolar bonds

Front 32

Define Hydrogen Bond

Back 32

A weak chemical attraction between a partially positive hydrogen atom of a polar molecule and a partially negative atom of another polar molecule

Front 33

Define Ionic Bond

Back 33

The bond that occurs when a cation binds to an anion

Front 34

Define Chemical Reaction

Back 34

The formation and breaking of chemical bonds, resulting in a change in the composition of substances

Front 35

Define Reactants

Back 35

A substance that participates in a chemical reaction and becomes changed by that reaction

Front 36

Define Products

Back 36

The end result of a chemical reaction

Front 37

Define Solute

Back 37

A substance dissolved in a liquid

Front 38

Define Solvent

Back 38

The liquid in which a solute is dissolved

Front 39

Define Solution

Back 39

A liquid that contains one or more dissolved solutes

Front 40

Define Aqueous Solution

Back 40

A solution in which the solvent is water

Front 41

Define Hydrophilic

Back 41

Water loving

Front 42

Define Hydrophobic

Back 42

Water fearing

Front 43

Define Amphipathic

Back 43

Molecules containing a hydrophobic region and a hydrophilic region

Front 44

Define Micelles

Back 44

The sphere formed by long amphipathic molecules when they are mixed with water. In animals, micelles aid in the absorption of poorly soluble products during digestion

Front 45

Define Concentration

Back 45

The amount of solute dissolved in a unit volume of solution

Front 46

Define Molecular Mass

Back 46

Molecular mass or molecular weight refers to the mass of a molecule. It is calculated as the sum of the mass of each constituent atom multiplied by the number of atoms of that element in the molecular formula

Front 47

Define Surface Tension

Back 47

A measure of how difficult it is to break the interface between a liquid and air

Front 48

Define Hydrolysis

Back 48

A chemical reaction that utilizes water to break apart molecules

Front 49

Define Condensation/Dehydration

Back 49

A type of condensation reaction in which a molecule of water is lost

Front 50

Define Acid

Back 50

A molecule that releases hydrogen ions (H+) in solution

Front 51

Define Base

Back 51

A molecule that when dissolved in water lowers the H+ concentration

Front 52

Define Buffer

Back 52

A compound that acts to minimize pH fluctuations in the fluids of living organisms. Buffer systems can raise or lower pH as needed

Front 53

Define Dissociate

Back 53

To split into separate smaller atoms, ions, or molecules, especially reversibly

Front 54

H+

Back 54

Hydrogen Ions

Front 55

OH-

Back 55

Hydroxide Ions

Front 56

pH

Back 56

A figure expressing the acidity or alkalinity of a solution on a logarithmic scale on which 7 is neutral, lower values are more acid, and higher values more alkaline. The pH is equal to -log10 c, where c is the hydrogen ion concentration in moles per liter

Front 57

Define Acidic

Back 57

A solution that has a pH below 7

Front 58

Define Alkaline

Back 58

A solution that has a pH above 7

Front 59

What are the four essential elements that compose the majority of living matter?

Back 59

C.H.O.N.
Carbon, Hydrogen, Oxygen, Nitrogen

Front 60

Explain how two isotopes of an element are the same and how they are different

Back 60

Isotopes are atoms of the same element that contain an identical number of protons, but a different number of neutrons. Despite having different numbers of neutrons, isotopes of the same element have very similar physical properties.

Front 61

Why is water polar?

Back 61

The unequal sharing of electrons gives the water molecule a slight negative charge near its oxygen atom and a slight positive charge near its hydrogen atoms. When a neutral molecule has a positive area at one end and a negative area at the other, it is a polar molecule

Front 62

List seven important functions of water

Back 62

1) Water participates in chemical reactions

2) Water provides support (plants)

3) Water is used to eliminate soluble wastes

4) Evaporation helps some animals dissipate body heat

5) The cohesive force of water molecules aids in the movement of fluid through vessels in plants

6) Water in saliva serves as a lubricant during - or as shown here, in anticipation of - feeding

7) The surface tension of water explains why this water strider doesn't sink.

Front 63

What is the bicarbonate buffering system?

Back 63

The bicarbonate buffering system is an important buffer system in the acid-base homeostasis of living things, including humans. As a buffer, it tends to maintain a relatively constant plasma pH and counteract any force that would alter.