BIOL: EXAM 1
One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH 6?
10,000 times more
What is the hydrogen ion (H+) concentration of a solution of pH 8?
10^-8 M
How many electrons are present in a Phosphorus 3+ atom?
12
The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (C atomic number is 6)?
14Si silicon
The first shell in any atom contains one orbital which may contain as many as
2 electrons
How many electrons does carbon share in order to complete its valence shell?
4
How many electrons will a single atom of sulfur with no charge and no bones have in its valence shell?
6
What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms?
6
Which of the following effects can occur because of the high surface tension of water?
A raft spider can walk across the surface of a small pond.
Which of the following is true for the reaction? 3H2 + N2 <-> 2NH3
Ammonia is being formed and decomposed simultaneously
Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms?
B
Visualize the structural formula of each of the following hydrocarbons. Which hydrocarbon has a double bond in its carbon skeleton?
C2H4
What is the difference between covalent bones and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms
Which drawing in the figure above is of the electron configuration of a sodium 11Na+ ion?
E
Buffers always release H+ ions into solution to stabilize pH
False
When water ionizes, the negatively charged OH fragment is the ________ ion.
Hydroxide
Eukaryotic cells differ from prokaryotic cells in that eukaryotic cells have...
Organelles
Which statement is true of all atoms that are anions?
The atom has more electrons than protons.
What determines if a molecule is polar or non polar?
The differences in the electronegativities of the atoms
Which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to them.
What results from the chemical reaction in the illustration? The reactants have no charge.
a cation with a net charge of +1 and an anion with a net charge of -1
Water moving up into a paper straw is attributable to...
adhesion
Buffers are substances that help resist shifts in pH by
both donating H+ to a solution when bases are added, and accepting H+ when acids are added.
The doctor prescribes a medicine to help stop wide fluctuations in stomach acid which have been causing you pain. The doctor probably prescribed a...
buffer
Water molecules are able to form hydrogen bonds with...
compounds that have polar covalent bonds
If the pH of a solution is increased from pH 5 to pH 7, it means that the
concentration of OH- is 100 times greater than what it was at pH 5.
A carbon atom is most likely to form what kind of bond(s) with other atoms?
covalent
Which of the following solutions has the greatest concentration of Hydrogen ions [H+]?
gastric juice at pH 2
Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? Testosterone and estradiol...
have different functional groups attached to the same carbon skeleton
All living things are able to maintain stable internal conditions, whether they are unicellular, or complex, multicellular organisms. This property is called...
homeostasis
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
hydrogen bond
Which of the following explains most specifically the attraction of water molecules to one another?
hydrogen bond
Which type of bond must be broken for water to vaporize?
hydrogen bonds
If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, then the concentration of H+ ions...
is 10 times higher in the cytoplasm than in the mitochondrial matrix
You are asked to indicate the type and number of atoms in a molecule. Which representation would work best?
molecular formula
Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal?
nervous system, brain, nervous tissue, nerve cell
A solution contains 0.0000001(10^-7) moles of hydroxide ions [OH-] per liter. Which of the following best describes this solution?
neutral
When two atoms are equally electronegative, they will interact to form...
nonpolar covalent bonds
Compared with 31P, the radioactive isotope 32P has...
one more neutron
A covalent chemical bond is one in which
outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms
What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M?
pH 2
What results from an unequal sharing of electrons between atoms?
polar covalent bond
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
polar covalent bonds
Based on your knowledge of the polarity of water molecules, the solute molecule depicted here is most likely...
positively charged
Which of the following solutions has the greatest concentration of hydroxyl ions [OH-]?
seawater at pH 8
If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that...
the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix.
Knowing just the atomic mass of an element allows inferences about which of the following?
the number of protons plus neutrons in the element
A group of cells that work together to carry out a similar function is known as a(n)
tissue
Which of the following is a hydrophobic material?
wax
The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (12/6 C)?
₁₄Si silicon
