Biology 121 Exam 1 Questions With All
Correct Answers
False statement about matter Correct answer-All mattere exists in the form of compounds
Describe a compound Correct answer-Contains two or more different elements in a fixed ratio
In the equation 2 H2 + O2 2 H2O Correct answer-only H2O is a compound
False statement regarding chemical reactions Correct answer-Some chemical reactions create
electrons; others destroy them
In the equation 2 H2 + O2 2 H2O, the H2 molecules are ________ and the H2O molecules are
________. Correct answer-reactants . . . products
Which particles are found in the nucleus of an atom? Correct answer-protons and neutrons
What is the atomic weight (mass) of an atom that has 6 protons, 6 neutrons, and 6 electrons?
Correct answer-About 12
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many
electrons does boron have? Correct answer-5
Describe the atomic number of an atom Correct answer-the number of protons in the atom
Chemical bonds result when two or more atoms share or donate: Correct answer-Electrons
Table salt is formed when: Correct answer-sodium donates its single outer electron to chlorine.
What is the fundamental difference between covalent and ionic bonding? Correct answer-In a
covalent bond, the partners share a pair of electrons; in an ionic bond, one partner accepts electrons
from the other.
In a water molecule, hydrogen and oxygen are held together by a(n) ________ bond. Correct
answer-polar bond (polar covalent bond)
The hydrogen atoms of a water molecule are bonded to the oxygen atom by ________ bonds,
whereas neighboring water molecules are held together by ________ bonds. Correct answer-polar
covalent . . . hydrogen
Water molecules stick to other water molecules because Correct answer-hydrogen bonds form
between the hydrogen atoms of one water molecule and the oxygen atoms of other water
molecules.
Photosynthesis requires many steps to make glucose but can be summarized as: 6CO2+
6H2O→C6H12O6 + 6O2
As a result of the synthesis process: Correct answer-all the carbons from the six carbon dioxide
atoms are found in glucose.
The tendency of water molecules to stick together is referred to as Correct answer-Cohesion
, Water's surface tension and heat storage capacity is accounted for by its Correct answer-Hydrogen
bonds
The temperature of evaporation is much higher for water than for alcohol. Without knowing more
about the chemistry of alcohol, which of the following is the most logical chemical explanation for
this phenomenon? Correct answer-Fewer hydrogen bonds form between alcohol molecules. As a
result, less heat is needed for alcohol molecules to break away from solution and enter the air.
What is a false statement about water? Correct answer-Ice is more dense than liquid water.
What is dependent on the ability of water molecules to form hydrogen bonds with other molecules
besides water? Correct answer-the universality of water as a solvent
A solution with a pH of 7 is: Correct answer-Neutral
Compared to a solution of pH 3, a solution of pH 1 is: Correct answer-100 times more acidic
State a true statement about pH: Correct answer-An increase in hydrogen ion concentration means
a decrease in pH scale units.
A buffer: Correct answer-donates H+ ions when conditions become too basic and accepts H+ ions
when conditions become too acidic.
Organic compounds: Correct answer-always contain carbon
The four most common elements in living organisms are: Correct answer-C, H, O, N
Which of the following is a trace element in the human body?
-cobalt
-nitrogen
-oxygen
-hydrogen Correct answer-Cobalt
False statement regarding carbon: Correct answer-Carbon has the ability to bond with up to six
other atoms.
A hydroxyl group is Correct answer-Characteristics of alcohols
Which of the following is a carboxyl group?
-COOH
-NH2
-OH
-CO Correct answer-COOH
Which of the following is an amino group?
-OH
-NH2
-CO
-COOH Correct answer-NH2
Correct Answers
False statement about matter Correct answer-All mattere exists in the form of compounds
Describe a compound Correct answer-Contains two or more different elements in a fixed ratio
In the equation 2 H2 + O2 2 H2O Correct answer-only H2O is a compound
False statement regarding chemical reactions Correct answer-Some chemical reactions create
electrons; others destroy them
In the equation 2 H2 + O2 2 H2O, the H2 molecules are ________ and the H2O molecules are
________. Correct answer-reactants . . . products
Which particles are found in the nucleus of an atom? Correct answer-protons and neutrons
What is the atomic weight (mass) of an atom that has 6 protons, 6 neutrons, and 6 electrons?
Correct answer-About 12
An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11. How many
electrons does boron have? Correct answer-5
Describe the atomic number of an atom Correct answer-the number of protons in the atom
Chemical bonds result when two or more atoms share or donate: Correct answer-Electrons
Table salt is formed when: Correct answer-sodium donates its single outer electron to chlorine.
What is the fundamental difference between covalent and ionic bonding? Correct answer-In a
covalent bond, the partners share a pair of electrons; in an ionic bond, one partner accepts electrons
from the other.
In a water molecule, hydrogen and oxygen are held together by a(n) ________ bond. Correct
answer-polar bond (polar covalent bond)
The hydrogen atoms of a water molecule are bonded to the oxygen atom by ________ bonds,
whereas neighboring water molecules are held together by ________ bonds. Correct answer-polar
covalent . . . hydrogen
Water molecules stick to other water molecules because Correct answer-hydrogen bonds form
between the hydrogen atoms of one water molecule and the oxygen atoms of other water
molecules.
Photosynthesis requires many steps to make glucose but can be summarized as: 6CO2+
6H2O→C6H12O6 + 6O2
As a result of the synthesis process: Correct answer-all the carbons from the six carbon dioxide
atoms are found in glucose.
The tendency of water molecules to stick together is referred to as Correct answer-Cohesion
, Water's surface tension and heat storage capacity is accounted for by its Correct answer-Hydrogen
bonds
The temperature of evaporation is much higher for water than for alcohol. Without knowing more
about the chemistry of alcohol, which of the following is the most logical chemical explanation for
this phenomenon? Correct answer-Fewer hydrogen bonds form between alcohol molecules. As a
result, less heat is needed for alcohol molecules to break away from solution and enter the air.
What is a false statement about water? Correct answer-Ice is more dense than liquid water.
What is dependent on the ability of water molecules to form hydrogen bonds with other molecules
besides water? Correct answer-the universality of water as a solvent
A solution with a pH of 7 is: Correct answer-Neutral
Compared to a solution of pH 3, a solution of pH 1 is: Correct answer-100 times more acidic
State a true statement about pH: Correct answer-An increase in hydrogen ion concentration means
a decrease in pH scale units.
A buffer: Correct answer-donates H+ ions when conditions become too basic and accepts H+ ions
when conditions become too acidic.
Organic compounds: Correct answer-always contain carbon
The four most common elements in living organisms are: Correct answer-C, H, O, N
Which of the following is a trace element in the human body?
-cobalt
-nitrogen
-oxygen
-hydrogen Correct answer-Cobalt
False statement regarding carbon: Correct answer-Carbon has the ability to bond with up to six
other atoms.
A hydroxyl group is Correct answer-Characteristics of alcohols
Which of the following is a carboxyl group?
-COOH
-NH2
-OH
-CO Correct answer-COOH
Which of the following is an amino group?
-OH
-NH2
-CO
-COOH Correct answer-NH2
