Bio

Front 1

the number of protons in an uncharged atom_

Back 1

equals the number of electrons.

Front 2

two atoms of the same element must have the same number of_

Back 2

protons.

Front 3

isotopes of an element will always differ in_

Back 3

atomic mass.

Front 4

a covalent bond is likely to be polar if_

Back 4

one of the atoms sharing electroms is much more electronegative.

Front 5

hydrogen bonds occur when_

Back 5

partial opposite charges on molecules come close enough to attract each other.

Front 6

the number of bonds atoms can form depends on:

Back 6

the number of valence electrons.

Front 7

an element has 9 protons, 10 neutrons, and 9 electrons. its atomic number and atomic mass respectively, are_

Back 7

9 and 19.

Front 8

the chemical characteristics of an element depend mostly on the

Back 8

number of electrons in its outer shell.

Front 9

oxygen is much more electronegative than hydrogen. which of the following statements is correct about H2O?

Back 9

each hydrogen atom has a partial positive charge.

Front 10

which of the following statements describes a reversible reaction that has reached chemical equilibrium?

Back 10

the rate of the reverse reaction equals the rate of the forward reaction.

Front 11

in a group of water molecules, hydrogen bonds form between_

Back 11

the oxygen atom and one water molecule and a hydrogen atom in another water molecule.

Front 12

when two atoms are equally electronegative, they can interact to form

Back 12

nonpolar covalent bonds.

Front 13

because molecules of water are farther apart in ice than in liquid water,

Back 13

ice floats.

Front 14

water is a very versatile solvent because water molecules are

Back 14

polar

Front 15

hydrophobic molecules are__water.

Back 15

repelled by

Front 16

an acid is

Back 16

a compound that donates hydrogen ions to a solution.

Front 17

a substance that minimizes changes in the concentration of H+ and OH- in a solution is a

Back 17

buffer

Front 18

what would be the pH of a solution with a hydroxide ion concentration (OH-)of 10^-8 M?

Back 18

6

Front 19

what do the following have in common with reference to water:cohesion, surface tension, specific heat?

Back 19

all are properties related to hydrogen bonding.

Front 20

a molecule that has all nonpolar covalent bonds would be_

Back 20

hydrophobic

Front 21

the carbon atom is tetravalent; this means that

Back 21

a carbon atom can complete its valence shell by forming four covalent bonds

Front 22

which of these is found in all amino acids?

Back 22

both -COOH and -NH2

Front 23

which one of the following molecules has a carboxyl functional group?

Back 23

R-COOH

Front 24

which of the following functional groups is associated with a release of energy that cells can harves to perform many funtions?

Back 24

phosphate

Front 25

which two functional groups are part of the monomers of polypeptides?

Back 25

carboxyl and amine

Front 26

a chemist wishes to make an organic molecule less acidic. which of the following functional groups should she add to the molecule?

Back 26

amino

Front 27

what is the process by which cells link monomers together to form polymers?

Back 27

dehydration/condensation synthesis

Front 28

cellulose is a _ made of many _.

Back 28

polymer... glucose molecules

Front 29

in what polysaccharide form do plants store glucose to be available later as an energy source?

Back 29

starch

Front 30

which one of the following components of a tossed salad will pass through the human digestive tract and be digested the least?

Back 30

cellulose (in the lettuce)