Bio 116 Exam 1
Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom?
1
How many molecules of glycerol (C3H8O3) would be present in 1 L of a 1 M glycerol solution?
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
The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius?
10.0°C
From its atomic number of 15, it is possible to predict that the phosphorus atom has how many protons and electrons?
15
How many structural isomers are possible for a substance having the molecular formula C4H10?
2
What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen?
2
Calcium has an atomic number of 20 and an atomic mass of 40. Therefore, a calcium atom must have how many protons
20
How many molecules of glucose (C6H2O6 molecular mass =180 daltons) would be present in one mole of glucose?
24
What is the approximate atomic mass of an atom with 16 neutrons, 15 protons, and 15 electrons?
31 daltons
How many electron pairs does carbon share in order to complete its valence shell?
4
What is the valence of an atom with six electrons in its outer electron shell?
4
One mole (mol) of a substance is ____
6.02 × 1023 molecules of the substance. the molecular mass of the substance expressed in grams.
You have a freshly-prepared 0.1M solution of glucose in water. Each liter of this solution contains how many glucose molecules?
6.02 × 10^22
How many electrons would be expected in the outermost electron shell of an atom with atomic number 12?
8
The atomic number of carbon is 6. Carbon-14 is heavier than carbon-12 because the atomic nucleus of carbon-14 contains ______ neutrons.
8
The atomic number of neon is 10. How many electrons in outer shell?
8
An example of a hydrogen bond is the bond between ______.
C and H in methane (CH4).
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms, and ionic bonds
True or False. Protons and electrons are electrically charged particles. Protons have one unit of negative charge, and electrons have one unit of positive charge.
False
Which of the following molecules contains the strongest polar covalent bond?2
H2
Which of the following ionizes completely in solution and is considered to be a strong acid?
HCl
A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
It should dissolve in water.
What is the mass and atomic mass number of a nitrogen atom contains 7 neutrons and 7 protons
Mass number 14 atomic number 14
Which of the following ionizes completely in solution and is considered to be a strong base? (alkali)?
NaOH
Why are hydrocarbons insoluble in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
Which of the following describes any reaction that has reached chemical equilibrium?
The rate of the forward reaction is equal to the rate of the reverse reaction.
Which of the following is a false statement concerning amino groups?
They are nonpolar.
Which of the following statements correctly describes geometric isomers?
They have variations in arrangement around a double bond.
Which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to t
Which of the following statements best describes the carbon atoms present in all organic molecules?
They were incorporated into organic molecules by plants. They were processed into sugars through photosynthesis. They are ultimately derived from carbon dioxide.
Atom of neon is inert. True or false
True
Based on electron configuration, sulfur would exhibit chemical behavior most like that of oxygen. True or False
True
Which is the best description of a carbonyl group?
a carbon atom joined to an oxygen by a double covalent bond
What results from an unequal sharing of electrons between atoms?
a polar covalent bond
A given solution contains 0.0001(10-4) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?
acidic; a good proton donor
A chemist wishes to make an organic molecule less acidic. Which of the following functional groups should be added to the molecule in order to do so?
amino
Which of the following contains nitrogen in addition to carbon, oxygen, and hydrogen?
an amino acid such as glycine
Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that ____.
an electron may move to an electron shell farther out from the nucleus
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?
an hydrogen bond
Oxygen has an atomic number of 8 and a mass number of 16. Thus, the atomic mass of an oxygen atom is __________.
approximately 16 daltons.
Research indicates that Ibuprofen, a drug used to relieve inflammation and pain, is a mixture of two enantiomers; that is, molecules that ____.
are mirror images of one another.
What indicates the number of protons in an atom's nucleus?
atomic number
Atoms whose outer electron shells contain eight electrons tend to ______.
be stable and chemically nonreactive, or inert.
Organic chemistry is a science based on the study of ____.
carbon compounds.
About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, oxygen
Which two functional groups are always found in amino acids?
carboxyl and amino
Which functional groups can act as acids?
carboxyl and phosphate
The ionic bond of sodium chloride is formed when _____.
chlorine gains an electron from sodium.
If the pH of a solution is decreased from 9 to 8, it means that the
concentration of H+ has increased 10-fold (10X) compared to what it was at pH 9. concentration of OH- has decreased to one-tenth (1/10) what it was at pH 9.
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
Which of the following explains most specifically the attraction of water molecules to one another?
hydrogen bond
What gives rise to the cohesiveness of water molecules?
hydrogen bonds
Which type of bond must be broken for water to vaporize?
hydrogen bonds
Which of the following results from a transfer of electron(s) between atoms?
ionic bond
Different atomic forms of an element contain the same number of protons but a different number of neutrons. What are these different atomic forms called?
isotopes
A solution contains 0.0000001(10-7) moles of hydroxyl 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
Hydrophobic substances such as vegetable oil are
nonpolar substances that repel water molecules.
How do isotopes of the same element differ from each other?
number of neutrons
A covalent bond is likely to be polar when ____.
one of the atoms sharing electrons is much more electronegative than the other a
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 is the pH of a solution with a hydrogen ion [H+] concentration of 10-8 M?
pH 8
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____.
polar covalent bonds
The mass number of an element can be easily approximated by adding together the number of _ in an atom of that element.
protons and neutrons
Buffers are substances that help resist shifts in pH by _____.
releasing H+ in acidic solutions.
Which of the following solutions has the greatest concentration of hydroxyl ions [OH-]?
seawater at pH 8
define a kilocalorie
the amount of heat required to raise the temperature of 1 kg of water by 1°C
Water is able to form hydrogen bonds because ____.
the bonds that hold together the atoms in a water molecule are polar covalent bo
Pure, freshly-distilled water has a pH of 7. This means that
the concentration of H+ ions in the water equals the concentration of OH- ions i
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
the nitrogen atom has a partial positive charge.
One difference between carbon-12 ( 12C) and carbon-14 (14C) is that carbon-14 has
two more neutrons than carbon-12.
3H is a radioactive isotope of hydrogen. One difference between hydrogen-1 ( 1H) and hydrogen-3 ( 3H) is that hydrogen-3 has
two more neutrons than hydrogen-1
