Chapter 2: The Chemical Context of Life
 
Pre-Test
 

Pre-Test


1 .       A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____. (Concept 2.1E-Book) [Hint]

 molecule
 element
 compound
 isotope
 proton


2 .       Which of the following is a trace element required by most living organisms? (Concept 2.1E-Book) [Hint]

 oxygen
 magnesium
 nitrogen
 carbon
 hydrogen


3 .       Which of the following subatomic particles always has a positive charge? (Concept 2.2E-Book) [Hint]

 proton
 neutron
 electron
 atom
 element


4 .       Changing the number of _____ would change an atom into an atom of a different element. (Concept 2.2E-Book) [Hint]

 bonds formed by an atom
 electrons circling the nucleus of an atom
 protons in an atom
 particles in the nucleus of an atom
 neutrons in an atom


5 .       The atoms of different phosphorus isotopes _____. (Concept 2.2E-Book) [Hint]

 have different atomic numbers
 have different numbers of neutrons
 react differently with other atoms
 have different numbers of electrons
 have different numbers of protons


6 .       How an atom chemically behaves when it comes into contact with other atoms is determined by its _____. (Concept 2.2E-Book) [Hint]

 nucleus
 size; smaller things are chemically more reactive
 protons
 neutrons
 electron configuration


7 .       Which of the following holds atoms together in a molecule? (Concept 2.3E-Book) [Hint]

 ionic bonds between atoms
 the transfer of protons from one atom to another
 the sharing of electrons between atoms
 the loss of neutrons by atoms
 the sharing of protons between atoms


8 .       Hydrogen bonding is most often seen _____. (Concept 2.3E-Book) [Hint]

 in molecules whose three-dimensional shape is tetrahedral
 when hydrogen is covalently bonded to an electronegative atom
 when multiple carbon atoms are present
 if the molecule consists of three or fewer atoms
 when the bonds within the molecule are nonpolar covalent bonds


9 .       An ionic bond is formed when _____. (Concept 2.3E-Book) [Hint]

 both atoms are equally attractive to electrons
 atoms are subjected to radioactive isotopes
 one atom transfers an electron to another atom
 both atoms are nonpolar
 both atoms are electrically neutral


10 .       Which of the following is not a chemical reaction? (Concept 2.4E-Book) [Hint]

 Glucose (C6H12O6) and oxygen gas (O2) combine to form carbon dioxide (CO2) and water (H2O).
 Sodium metal and chlorine gas Cl2 unite to form sodium chloride (NaCl).
 Hydrogen gas (H2) combines with oxygen gas (O2) to form liquid water (H2O).
 Solid ice melts to form liquid water.







©2005 Pearson Education, Inc., publishing as Benjamin Cummings