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Biology 121 JCCC Exam Questions and Answers
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Biology 121 JCCC Exam Questions and Answers
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Biology 121 JCCC Exam Questions andAnswers
False statement about matter - Answer-All mattere exists in the form of compounds
Describe a compound - Answer-Contains two or more different elements in a fixed ratio
In the equation 2 H2 + O2 2 H2O - Answer-only H2O is a compound
False statement regarding chemical reactions - 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 ________. - Answer-reactants . . . products
Which particles are found in the nucleus of an atom? - Answer-protons and neutrons
What is the atomic weight (mass) of an atom that has 6 protons, 6 neutrons, and 6
electrons? - 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? - Answer-5
Describe the atomic number of an atom - Answer-the number of protons in the atom
Chemical bonds result when two or more atoms share or donate: - Answer-Electrons
Table salt is formed when: - Answer-sodium donates its single outer electron to
chlorine.
What is the fundamental difference between covalent and ionic bonding? - 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. -
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. -
Answer-polar covalent . . . hydrogen
Water molecules stick to other water molecules because - 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: - 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 - Answer-Cohesion
Water's surface tension and heat storage capacity is accounted for by its - 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? - 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? - 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? - Answer-the universality of water as a solvent
A solution with a pH of 7 is: - Answer-Neutral
Compared to a solution of pH 3, a solution of pH 1 is: - Answer-100 times more acidic
State a true statement about pH: - Answer-An increase in hydrogen ion concentration
means a decrease in pH scale units.
A buffer: - Answer-donates H+ ions when conditions become too basic and accepts H+
ions when conditions become too acidic.
Organic compounds: - Answer-always contain carbon
The four most common elements in living organisms are: - Answer-C, H, O, N
Which of the following is a trace element in the human body?
-cobalt
-nitrogen
-oxygen
-hydrogen - Answer-Cobalt
False statement regarding carbon: - Answer-Carbon has the ability to bond with up to
six other atoms.
A hydroxyl group is - Answer-Characteristics of alcohols
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