Exam 1 Flashcards
A carbon atom has 6 electrons total, but only 4 valence electrons. Why?
Carbon has two electrons in its first electron shell and four in its second
On a hot day, the temperature of the land rises more quickly than that of the sea. Which of these statements describes that process?
The specific heat of soil is less than water
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?
The hydrocarbon chain with all single bonds will be linear in structure
As the H+ concentration of a solution decreases, the OH- concentration of that solution:
increases and thus the pH increases
An ion that consists of 7 protons, 6 neutrons, and 11 electrons has a net charge of:
4-
How would you write out the symbol for a sodium ion that has lost one electron?
Na+
In an aqueous solution, the weakest type of chemical interaction is:
van der Waal’s forces
In the term trace element, the adjective trace means:
the element is required in very small amounts
For an atom that is not an ion, which statement must be true?
The number of electrons equals the number of protons
When atoms have an equal number of electrons and protons:
they have no electric charge
Which of the following types of bond is broken when water evaporates?
hydrogen bonds
Which of the following lists the given elements in order of decreasing electronegativity?
O, N, C/S/P/H
Which of the following is NOT found in the nucleus of an atom?
electrons
If an atom has a charge of +1, which of the following must be true?
It has one more proton than it does electrons
When carbon and hydrogen form a covalent bond, which of the following is true?
It is a non-polar covalent bond, because C and H have similar electronegativity
When a H atom becomes an H+ ion, it:
loses an electron
Which type of bond is being described? Electrons are shared equally between two atoms
Nonpolar Covalent
Which elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, oxygen
Surface tension is a result of which of the following properties of water:
Cohesion
Nonpolar substances:
are hydrophobic and repel water molecules
One water molecule can bond to other water molecules through _____ bonds.
Hydrogen
Water’s high specific heat is due to the fact that:
energy that would otherwise be used to heat water is instead used to break hydrogen bonds among water molecules
The bonds that hold each hydrogen atom and the oxygen atom together within a single water molecule are:
covalent bonds
Which of the following is NOT true of water?
It is not a good solvent
A buffer is a chemical that
Can act either as an acid or a base
Which of the following is an accurate description of hydrophobic substances?
Nonpolar substances that repel water molecules
A base is best defined as:
A substance that removes H+ ions from a solution by reacting with them
Water in its liquid state:
has a very high heat of vaporization compared to other substances
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?
Acidic, more
What kind of bonds are responsible for the unique cohesion, surface tension, and adhesion properties of water molecules?
hydrogen bonds
Which number represents the pH of a solution with the lowest concentration of hydrogen ions?
11.5
What kind of molecule is ATP?
nucleotide
The level of protein structure least affected by a disruption in hydrogen bonding is:
primary
What is the difference between a ribonucleotide and a deoxyribonucleotide?
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
What type of protein will always have quaternary structure?
A protein made from multiple polypeptide chains
The main energy-storage polysaccharide in plants is:
starch
Which of these is NOT a lipid?
starch
The variable part of an amino acid is:
the R group
Three fatty acids bonded together with a glycerol are found in a(n)
triglyceride
Why can humans digest starch but not cellulose?
Humans have enzymes that can break down starch but none that can break the bonds holding cellulose together
The variable portion of a DNA nucleotide is:
the base
Alpha helixes and beta pleated sheets are examples of which level of protein structure?
secondary
A glycosidic linkage in a polysaccharide is the equivalent of which of the following in proteins?
a peptide bond
The most abundant type of macromolecule in cells is:
protein
Which two functional groups are part of the structure of an amino acid?
carboxyl; amino
Carbon is important for life because:
All of the above are correct
Chemicals that have the same chemical formula but different chemical structures are called:
isomers
Why is there so much variety among organic molecules?
Because of carbon’s many different chemical properties
