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Biology 121 JCCC __ Exam 1 Questions and Answers Graded A+
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Biology 121 JCCC __ Exam 1
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Biology 121 JCCC __ Exam 1False statement about matter - answer All mattered 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? - answer5
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: - answerall the carbons from the six carbon dioxide
atoms are found in glucose.
The tendency of water molecules to stick together is referred to as - answerCohesion
Water's surface tension and heat storage capacity is accounted for by its -
answerHydrogen 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? - answerFewer 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? - answerIce is more dense than liquid water.
What is dependent on the ability of water molecules to form hydrogen bonds with other
molecules besides water? - answerthe universality of water as a solvent
A solution with a pH of 7 is: - answerNeutral
Compared to a solution of pH 3, a solution of pH 1 is: - answer100 times more acidic
State a true statement about pH: - answerAn increase in hydrogen ion concentration
means a decrease in pH scale units.
A buffer: - answerdonates H+ ions when conditions become too basic and accepts H+
ions when conditions become too acidic.
Organic compounds: - answeralways contain carbon
The four most common elements in living organisms are: - answerC, H, O, N
Which of the following is a trace element in the human body?
-cobalt
-nitrogen
-oxygen
-hydrogen - answerCobalt
False statement regarding carbon: - answerCarbon has the ability to bond with up to six
other atoms.
A hydroxyl group is - answerCharacteristics of alcohols
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