Chapter 2: The Chemical Level - PART 1

Question 1

______, have neither a definite shape nor volume

Answer 1

gases

Question 2

What is are chemical elements? how many are there? how many naturally occur on earth?

Answer 2

limited number of building blocks that make up All forms of matter—both living and nonliving— .Each element is a substance that cannot be split into a simpler substance by ordinary chemical means. 117 elements, 92 occur naturally on Earth.

Question 3

What 4 major elements, con- stitute about 96% of the body’s mass

Answer 3

oxygen (O), carbon (C), hydrogen (H), and nitrogen (N)

Question 4

What Eight others lesser elements, contribute about 3.6% to the body’s mass

Answer 4

calcium (Ca), phosphorus (P), potassium (K), sulfur (S), sodium (Na), chlorine (Cl), magnesium (Mg), and iron (Fe)

Question 5

What n additional 14 elements—the trace elements—are present in tiny amounts (make up 0.4%) Don’t think you have to know this….

Answer 5

Aluminum (Al), boron (B), chromium (Cr), cobalt (Co), copper (Cu), fluorine (F), iodine (I), manganese (Mn), molybdenum (Mo), selenium (Se), silicon (Si), tin (Sn), vanadium (V), and zinc (Zn).

Question 6

define atoms

Answer 6

make up each element - they are the smallest units of matter that retain the properties and characteristics of the element.

Question 7

what three types of subatomic particles are im- portant for understanding the chemical reactions in the human body

Answer 7

protons, neutrons, and electrons

Question 8

define protons. neutrons and electrons

Answer 8

Within the nucleus are positively charged protons (p􏰈) and uncharged (neutral) neutrons (n0). The tiny, negatively charged electrons (e􏰊) move about in a large space surrounding the nucleus

Question 9

what is a nucleus

Answer 9

The dense central core of an atom

Question 10

What are electron shells? how many electrons does each hold?

Answer 10

The first electron shell (nearest the nucleus) never holds more than 2 electrons. The second shell holds a maximum of 8 electrons, and the third can hold up to 18 electrons

Question 11

The number of electrons in an atom of an element always equals the number of _____ thus each atoms total charge is____

Answer 11

protons, zero

Question 12

what is an atom’s atomic number?

Answer 12

The number of protons in the nucleus of an atom

Question 13

what is an atom’s mass number?

Answer 13

the sum of its protons and neutrons

Question 14

Although all atoms of one element have the same number of _____, they may have different numbers of _____ and thus different ________

Answer 14

protons, neutrons, mass numbers

Question 15

Define isotopes

Answer 15

atoms of an element that have different numbers of neutrons and therefore different mass numbers

Question 16

what are radioactive isotopes?

Answer 16

unstable isotopes; their nuclei decay (spontaneously change) into a stable configuration. During which they emit radiation and may transform into a different element

Question 17

whats the half life of an isotope

Answer 17

time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form

Question 18

what is a dalton

Answer 18

The standard unit for measuring the mass of atoms and their sub- atomic particles

Question 19

What is the atomic mass?

Answer 19

the average mass of all its naturally occurring isotopes.

Question 20

what is an Ion

Answer 20

an atom that has a positive or negative charge because it has unequal numbers of protons and electrons. (occurs when an atom gives up or gains electrons = ionization)

Question 21

When two or more atoms share electrons, the resulting combi- nation is called a _______

Answer 21

molecule

Question 22

define a compound

Answer 22

a substance that contains atoms of two or more different elements (ex. H20)

Question 23

Define a free radical

Answer 23

an atom or group of atoms with an unpaired electron in the outermost shell = unstable,highly reactive and destructive to nearby molecules (ex. superoxide)

Question 24

The forces that hold together the atoms of a molecule or a com- pound are called ________

Answer 24

chemical bonds

Question 25

The likelihood that an atom will form a chemical bond with another atom depends on the number of electrons in its outermost shell, also called the _________

Answer 25

Valence shell

Question 26

what determines if a molecule is chemically stable

Answer 26

if it has 8 electrons on it’s valence shell

Question 27

What is the octet rule?

Answer 27

One atom is more likely to interact with another atom if doing so will leave both with eight valence electrons

Question 28

What’s an ionic bond?

Answer 28

The force of attraction that holds together ions with opposite charges

Question 29

What is a cation?

Answer 29

the total number of protons exceeds the number of electrons resulting in a positively charged ion

Question 30

What is an anion?

Answer 30

the total number of electrons exceeds the number of protons resulting in a negatively charged ion

Question 31

Where are most ionic bonds found in the body?

Answer 31

teeth and bones

Question 32

What is an electrolyte? what happens to ionic compounds in the body?

Answer 32

An ionic compound that breaks apart into positive and negative ions in solution - ex. ionic compounds in body break apart in body fluids as electrolytes and can conduct electricity

Question 33

Define a covalent bond

Answer 33

when two or more atoms share electrons rather than gaining or losing them ***The larger the number of electron pairs shared between two atoms, the stronger the covalent bond.

Question 34

what is the most common chemical bond in the body, and the compounds that result from them form most of the body’s structures.

Answer 34

covalent bonds

Question 35

what is a nonpolar covalent bond? (example)

Answer 35

two atoms share the electrons equally—one atom does not attract the shared electrons more strongly than the other atom ex. b/w two identical atoms 02

Question 36

What is a polar covalent bond? (example)

Answer 36

the sharing of electrons between two atoms is unequal—the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom. *** the resulting molecule has a partial negative charge (electronegativeity) near the atom that attracts electrons more strongly. ex. H20 (oxygen attrcts more strongly)

Question 37

What is electronegativeity?

Answer 37

, the power to attract electrons to itself

Question 38

what is a hydrogen bond?

Answer 38

forms when a hydrogen atom with a partial positive charge attracts the partial negative charge of neighbouring electronegative atoms, most often larger oxygen or nitrogen atoms. ***weaker than ionic or covalent bonds so they don’t form molecules

Question 39

The hydrogen bonds that link neighboring water molecules give water considerable ______ ( the tendency of like particles to stay together)

Answer 39

cohesion

Question 40

The cohesion of water molecules creates a very high _____-, a measure of the difficulty of stretching or breaking the surface of a liquid

Answer 40

surface tension

Question 41

what is a chemical reaction?

Answer 41

when new bonds form or old bonds break between atoms. Chemical reactions are the foundation of all life processes

Question 42

. In a chemical reaction, the total mass of the ______ equals the total mass of the _______

Answer 42

reactants, products

Question 43

define metabolism

Answer 43

all the chemical reactions occurring in the body.

Question 44

what are the 3 types of energy?

Answer 44

potential energy, energy stored by matter due to its position, kinetic energy, the energy associated with matter in motion. Chemical energy is a form of potential energy that is stored in the bonds of compounds and molecules

Question 45

what are exergonic and endergonic reactions

Answer 45

Exergonic reactions (ex- = out) release more energy than they absorb. By contrast, endergonic reactions (end- = within) absorb more energy than they release.

Question 46

The collision energy needed to break the chemical bonds of the reactants is called the _________

Answer 46

activation energy

Question 47

how do concentration and temperature influence the liklihood that collision will occur?

Answer 47

Concentration. The more particles of matter present in a confined space, the greater the chance that they will collide • Temperature. As temperature rises, particles of matter move about more rapidly

Question 48

What are catlysts? what are the most important catalysts in the body?

Answer 48

chemical compounds that speed up chemical reactions by lower- ing the activation energy needed for a reaction to occur - enzymes

Question 49

How exactly does a catalyst assist a chemical reaction?

Answer 49

A catalyst helps to properly orient the colliding particles and lowers activation energy

Question 50

What is a synthesis reaction

Answer 50

When two or more atoms, ions, or molecules combine to form new and larger molecule

Question 51

All the synthesis reactions that occur in your body are collectively referred to as _______

Answer 51

anabolism

Question 52

anabolic reactions are usually _______ because they absorb more energy than they release.

Answer 52

endergonic

Question 53

what are decompositional reactions?

Answer 53

reaction that splits up large molecules into smaller atoms, ions, or molecules

Question 54

The decomposition reactions that occur in your body are collectively referred to as ________

Answer 54

catabolism

Question 55

Overall, catabolic reactions are usually ________because they release more energy than they absorb.

Answer 55

exergonic

Question 56

what is an exchange reaction?

Answer 56

both synthesis and decomposition reactions.

Question 57

what is a reversible reaction?

Answer 57

the products can revert to the original reactants.

Question 58

define oxidization and reduction

Answer 58

Oxidation refers to the loss of electrons, and in the process the oxidized substance releases energy. Reduction refers to the gain of electrons, and in the process the reduced substance gains energy. *** oxidization-reduction rxns always occur in parallel

Question 59

what are inorganic compunds? what do they include? What type of bonds do they have?

Answer 59

usually lack carbon and are structurally simple. Their molecules also have only a few atoms and cannot be used by cells to perform complicated biological functions. They include water and many salts, acids, and bases. have either ionic or covalent bonds