Chemistry of Life: Chp 2

Question 1

matter

Answer 1

anything that takes up space and has mass

Question 2

element

Answer 2

a substance that cannot be broken down to other substances by chemical reactions EX: gold, copper

Question 3

compound

Answer 3

a substance consisting of two or more elements combined in a fixed ratio EX: water and table salt

Question 4

4 Major elements in the human body

Answer 4

C, H, N, O…make up 96% of living matter

Question 5

trace elements in the human body

Answer 5

elements that are required by an organism in only minute quantities…Iron and iodine

Question 6

atoms

Answer 6

the smallest unit of an element that still retains the property of the element. Atoms are made up of neutrons, protons, and electrons.

Question 7

protons

Answer 7

positively charged particles. they are found in the nucleus and determine the element

Question 8

electrons

Answer 8

negatively charged particles that are found in electron shells around the nucleus. they determine the chemical properties and reactivitiy of the element

Question 9

neutrons

Answer 9

particles with no charge. they are found in the nucleus. their number can vary in the same element, resulting in isotopes.

Question 10

isotopes

Answer 10

are forms of an element with differing numbers of neutrons. EX: 12C and 14C are isotopes of carbon. Both have 6 protons, but 12C has 6 neutrons whereas 14C has 8 neutrons

Question 11

atomic number

Answer 11

number of protons an element possesses. this number is uinue to every element

Question 12

mass number

Answer 12

an element is the sum of its protons and neutrons

Question 13

chemical bonds

Answer 13

defined as interactions between the valence electrons of different atoms. atoms are held together by chemical bonds to form molecules

Question 14

covalent bonds

Answer 14

occur when valence electrons are shared by two atoms

Question 15

nonpolar covalent bonds

Answer 15

occur when the electrons being shared are shared equally between the two atoms

Question 16

electronegatively

Answer 16

a tendency to attract electrons of a covalent bond.

Question 17

polar covalent bond

Answer 17

one atom has greater electronegativity than the other, resulting in an unequal sharing of the electrons

Question 18

ionic bonds

Answer 18

are ones in which two atoms attract valence electrons so unequally that the more electronegative atom seals the electron away from the less electronegative atom

Question 19

ion

Answer 19

the resulting charged atom or molecule

Question 20

ionic bonds

Answer 20

occur because these ions will be either positively or negatively charged, and will be attracted to each other by these opposite charges

Question 21

hydrogen bonds

Answer 21

relatively weak bonds that form between the partial positively charged hydrogen atom of one molecule and the strongly electronegative oxygen or nitrogen of another molecule

Question 22

van der waals interactions

Answer 22

very weak, transient connections that are the result of asymmetrical distribution of electrons within a molecule. these weak interactions contribute to the three-dimensional shape of molecules

Question 23

chemical reaction

Answer 23

shows the reactants, which are the starting materials, an arrow to indicate their conversion into the products, the ending materials

Question 24

reactants

Answer 24

starting materials

Question 25

products

Answer 25

ending materials

Question 26

chemical equilibrium

Answer 26

the point at which the forward and reverse reactions offset one another exactly. their concentrations have stabilized at a particular ratio, though they are not necessarily equal