Exam 1

Question 1

A carbon atom has 6 electrons total, but only 4 valence electrons. Why?

Answer 1

Carbon has two electrons in its first electron shell and four in its second

Question 2

On a hot day, the temperature of the land rises more quickly than that of the sea. Which of these statements describes that process?

Answer 2

The specific heat of soil is less than water

Question 3

How does a hydrocarbon chain with all of the carbons linked by single bonds compare to a hydrocarbon chain where some of the carbons are linked by double bonds?

Answer 3

The hydrocarbon chain with all single bonds will be linear in structure

Question 4

As the H+ concentration of a solution decreases, the OH- concentration of that solution:

Answer 4

increases and thus the pH increases

Question 4

An ion that consists of 7 protons, 6 neutrons, and 11 electrons has a net charge of:

Answer 4

4-

Question 5

How would you write out the symbol for a sodium ion that has lost one electron?

Answer 5

Na+

Question 6

In an aqueous solution, the weakest type of chemical interaction is:

Answer 6

van der Waal’s forces

Question 7

In the term trace element, the adjective trace means:

Answer 7

the element is required in very small amounts

Question 7

For an atom that is not an ion, which statement must be true?

Answer 7

The number of electrons equals the number of protons

Question 8

When atoms have an equal number of electrons and protons:

Answer 8

they have no electric charge

Question 9

Which of the following types of bond is broken when water evaporates?

Answer 9

hydrogen bonds

Question 10

Which of the following lists the given elements in order of decreasing electronegativity?

Answer 10

O, N, C/S/P/H

Question 11

Which of the following is NOT found in the nucleus of an atom?

Answer 11

electrons

Question 12

If an atom has a charge of +1, which of the following must be true?

Answer 12

It has one more proton than it does electrons

Question 13

When carbon and hydrogen form a covalent bond, which of the following is true?

Answer 13

It is a non-polar covalent bond, because C and H have similar electronegativity

Question 14

When a H atom becomes an H+ ion, it:

Answer 14

loses an electron

Question 15

Which type of bond is being described? Electrons are shared equally between two atoms

Answer 15

Nonpolar Covalent

Question 16

Which elements make up approximately 96% of living matter?

Answer 16

carbon, hydrogen, nitrogen, oxygen

Question 17

Surface tension is a result of which of the following properties of water:

Answer 17

Cohesion

Question 18

Nonpolar substances:

Answer 18

are hydrophobic and repel water molecules

Question 19

One water molecule can bond to other water molecules through _____ bonds.

Answer 19

Hydrogen

Question 20

Water’s high specific heat is due to the fact that:

Answer 20

energy that would otherwise be used to heat water is instead used to break hydrogen bonds among water molecules

Question 21

The bonds that hold each hydrogen atom and the oxygen atom together within a single water molecule are:

Answer 21

covalent bonds

Question 22

Which of the following is NOT true of water?

Answer 22

It is not a good solvent

Question 23

A buffer is a chemical that

Answer 23

Can act either as an acid or a base

Question 24

Which of the following is an accurate description of hydrophobic substances?

Answer 24

Nonpolar substances that repel water molecules

Question 25

A base is best defined as:

Answer 25

A substance that removes H+ ions from a solution by reacting with them

Question 26

Water in its liquid state:

Answer 26

has a very high heat of vaporization compared to other substances

Question 27

A solution has a pH of 4. Is this considered acidic or basic, and does it contain more or fewer H+ ions than a solution with pH 7?

Answer 27

Acidic, more

Question 28

What kind of bonds are responsible for the unique cohesion, surface tension, and adhesion properties of water molecules?

Answer 28

hydrogen bonds

Question 29

Which number represents the pH of a solution with the lowest concentration of hydrogen ions?

Answer 29

11.5

Question 30

What kind of molecule is ATP?

Answer 30

nucleotide

Question 31

The level of protein structure least affected by a disruption in hydrogen bonding is:

Answer 31

primary

Question 32

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Answer 32

Ribonucleotides have a hydroxyl group on the 2’ carbon of their sugar subunit; deoxyribonucleotides have a hydrogen on the 2’ carbon of their sugar subunit

Question 33

What type of protein will always have quaternary structure?

Answer 33

A protein made from multiple polypeptide chains

Question 34

The main energy-storage polysaccharide in plants is:

Answer 34

starch

Question 35

Which of these is NOT a lipid?

Answer 35

starch

Question 36

The variable part of an amino acid is:

Answer 36

the R group

Question 37

Three fatty acids bonded together with a glycerol are found in a(n)

Answer 37

triglyceride

Question 38

Why can humans digest starch but not cellulose?

Answer 38

Humans have enzymes that can break down starch but none that can break the bonds holding cellulose together

Question 39

The variable portion of a DNA nucleotide is:

Answer 39

the base

Question 40

Alpha helixes and beta pleated sheets are examples of which level of protein structure?

Answer 40

secondary

Question 41

A glycosidic linkage in a polysaccharide is the equivalent of which of the following in proteins?

Answer 41

a peptide bond

Question 42

The most abundant type of macromolecule in cells is:

Answer 42

protein

Question 43

Which two functional groups are part of the structure of an amino acid?

Answer 43

carboxyl; amino

Question 44

Carbon is important for life because:

Answer 44

All of the above are correct

Question 45

Chemicals that have the same chemical formula but different chemical structures are called:

Answer 45

isomers

Question 46

Why is there so much variety among organic molecules?

Answer 46

Because of carbon’s many different chemical properties