Bio Ch 2

Question 0

Elements

Answer 0

Substance that cannot be broken down to simpler substances with different properties

Question 1

Matter

Answer 1

Anything that takes up space and has mass

Question 2

CHNOPS

Answer 2

Carbon, hydrogen, nitrogen, oxygen, phosporus, & sulfur- basic elements of life (95% of the body weight of organisms)

Question 3

Atom

Answer 3

Smallest part of an element that displays the properties of the element

Question 4

atomic symbol

Answer 4

1-2 letters that represent an element’s name

Question 5

Proton

Answer 5

Positively charged subatomic particle

Question 6

Neutrons

Answer 6

Uncharged subatomic particles

Question 7

Electrons

Answer 7

Negatively charged subatomic particles (Gk, elektron, electricity)

Question 8

Electron shell

Answer 8

average location of electrons

Question 9

Atomic number

Answer 9

of protons in the nucleus; accounts for unique properties of the atom

Question 10

Mass number

Answer 10

sum of protons and neutrons in nucleus

Question 11

Atomic mass

Answer 11

average of the AMU for all isotopes of that number

Question 12

Isotopes

Answer 12

Gk, isos, equal & topos, place; atoms of the same element that differ in the number of neutrons

Question 13

Tracer

Answer 13

small amount of a radioactive isotope in a sample to detect molecular changes

Question 14

Octet rule

Answer 14

outermost shell of an atom is most stable when it has eight electrons

Question 15

Valence shell

Answer 15

atoms use electrons in this shell to undergo reactions; # of electrons determines whether the atom gives up, accepts, or shares electrons to acquire 8 in the outer shell

Question 16

Molecule

Answer 16

Latin = moles, “mass”; 2+ elements bond together; smallest part of a compound that retains its chemical properties

Question 17

Compound

Answer 17

molecule with at least 2 elements

Question 18

Formula

Answer 18

number of each kind of atom in a molecule

Question 19

Ions

Answer 19

charged particles

Question 20

Ionic bond

Answer 20

strong attraction between negatively and positively charged ions that holds ionic compounds together

Question 21

Salts

Answer 21

solid substances that usually separate and exist as individual ions in water

Question 22

Covalent bond

Answer 22

Latin, co, together/with & valens, strength); 2 atoms share electrons in such a way that each atom has an octet of electrons in the outer shell (or 2 electrons, in the case of hydrogen)

Question 23

Nonpolar covalent bond

Answer 23

sharing of electrons between 2 atoms are equal

Question 24

Electronegativity

Answer 24

ability to attract electrons; dependent on number of protons (the greater the protons, the greater the electronegativity)

Question 25

Polar covalent bond

Answer 25

when electrons are not shared equally

Question 26

Hydrogen bond

Answer 26

attraction of a slightly positive hydrogen to a slightly negative atom in the vicinity

Question 27

Calorie

Answer 27

amount of heat energy needed to raise the temperature of 1g of water 1 degree Celsius

Question 28

Solution

Answer 28

fluid that contains a dissolved solid

Question 29

Solute

Answer 29

Dissolved substances in solution

Question 30

Hydrophilic

Answer 30

molecules that can attract water (Gk, hydrias, of water & phileo, love)

Question 31

Hydrophobic

Answer 31

nonionized and nonpolar molecules that cannot attract water (Gk, hydrias, of water & phobia, fear)

Question 32

Cohesion

Answer 32

ability of water molecules to cling to each other due to hydrogen bonding

Question 33

Adhesion

Answer 33

ability of water molecules to cling to other polar surfaces

Question 34

Surface tension

Answer 34

force that holds moist membranes together due to the attraction of water molecules through hydrogen bonds

Question 35

Hydrogen ions (H+)

Answer 35

Protons; hydrogen atom that has lost its electron and therefore bears a positive charge

Question 36

Hydroxide ions (OH-)

Answer 36

1 of 2 ions that results when a water molecule dissociates; it has gained an electron and therefore bears a negative charge

Question 37

Acids

Answer 37

substances that dissociate in water, releasing hydrogen ions (H+); acidity depends on how fully it dissociates in water

Question 38

Bases

Answer 38

Substances that either take up hydrogen ions (H+) or release hydroxide ions (OH-)

Question 39

pH scale

Answer 39

used to indicate the acidity or basicity/alkalinity of a solution

Question 40

Buffer

Answer 40

chemical or combo of chemicals that keeps pH within normal limits