Chapter 2- The Chemical Basis of Life (PSU science day)
. Electron position within an atom ________. A. can be determined precisely B. can be approximated C. is designated by the atomic number D. is totally unknown
B. can be approximated
Which of the following is a partial list of the elements which make up 98% of most living organisms? A. calcium, carbon, sulfur B. carbon, hydrogen, oxygen C. oxygen, phosphorus, iron D. nitrogen, calcium, iron
B. carbon, hydrogen, oxygen
. Chemical bonding occurs in order to ________. A. form ions B. fill valence shells C. eliminate radioactivity D. increase energy in a compound
B. fill valence shells
The property of water which allows some insects to walk on water and provides habitats for aquatic organisms from floating plant debris is its ________. A. high heat capacity B. high surface tension C. high heat of vaporization D. high density as a solid
B. high surface tension
. After drinking a great deal of coffee (pH 5), a human's blood buffering system would need to ___ as the coffee was digested. A. release OH- B. take up H+ C. release H+ D. take up OH-
B. take up H+
Certain isotopes can be used as tracers for medical purposes in humans because ________. A. of their stability B. they emit radioactivity C. of their high energy electrons D. they are heavier
B. they emit radioactivity
Water is polar because of ________. A. transfer of electrons B. unequal sharing of electrons C. its ability to freeze D. its hydrogen bonds
B. unequal sharing of electrons
Aquatic organisms are protected from freezing in northern climates because ________. A. water is more dense when solid B. water expands and is less dense when solid C. water cannot form a solid D. None of the choices are correct.
B. water expands and is less dense when solid
The nucleus of an atom has a positive charge because of the ________. A. protons B. electrons C. positrons D. neutrons
A. protons
The pH scale is a mathematical indicator of ________. A. the amount of H+ present in a solution B. the amount of OH- present in a solution C. the total amount of all ions in a solution D. the ability of a solution to buffer
A. the amount of H+ present in a solution
. Sodium has a mass number of 23 and an atomic number of 11. How many neutrons are present? A. 11 B. 12 C. 23 D. 34
B. 12
A pH 5 solution has ___ times the number of H+ ions present as a pH 7 solution. A. 10 B. 20 C. 100 D. 1000
C. 100
. Glucose, C6H12O6, is best described as ________. A. an element B. an isotope C. a compound D. an ion
C. a compound
. A covalent bond occurs when ________. A. protons are transferred from one atom to another B. neutrons are shared between two atoms to form an isotope C. electrons are shared between two atoms to fill valence shells D. None of the choices are correct.
C. electrons are shared between two atoms to fill valence shells
. Which of the following would have the same identifying name? A. elements and compounds B. compounds and atoms C. elements and atoms D. None of the choices are correct.
C. elements and atoms
The periodic table is arranged ________. A. alphabetically B. by importance of elements to living organisms C. in part by the number of electron shells atoms have D. in order of discovery
C. in part by the number of electron shells atoms have
. Matter ________. A. is a substance which cannot be broken down into another substance by ordinary chemical means B. is the ability to do work C. is anything which takes up space and has mass D. different in mass on Earth than on the moon
C. is anything which takes up space and has mass
Carbon typically has a mass number of 12. Carbon with a mass number of 14 ________. A. has two additional electrons B. has two additional protons C. is called an isotope D. has two additional protons and is called an isotope
C. is called an isotope
When a sodium atom transfers an electron to a chlorine atom ________. A. the sodium atom becomes a positively charged ion B. the positive and negative ions will attract each other, forming a crystal if no water is present C. the ions will separate in the presence of water D. All of the choices are correct
D. All of the choices are correct
Hydrogen bonding is important in which of the following properties of water? A. ability to dissolve many substances B. cohesiveness C. high heat capacity D. All of the choices are correct.
D. All of the choices are correct.
In Fig. 2.1 ________. A. the letters represent atoms B. the angle of the lines represents the real angles found in the molecule C. the lines represent chemical bonds D. All of the choices are correct.
D. All of the choices are correct.
Bases can ________. A. release hydrogen ions B. take up hydrogen ions C. release hydroxide ions D. both take up hydrogen ions and release hydroxide ions
D. both take up hydrogen ions and release hydroxide ions
Elements differ from each other in their ________. A. physical properties B. atomic mass C. the type of subatomic particles they have D. both their physical properties and atomic mass
D. both their physical properties and atomic mass
The ability of water molecules to flow without separating is due to water's ________. A. ionic bonding ability B. hydrophobic properties C. adhesiveness D. cohesiveness
D. cohesiveness
. An atom which has three shells is said to be stable if ________. A. it has 2 electrons in its first shell B. it follows the octet rule C. it has 8 electrons in its valence shell D. it follows the octet rule, having 8 electrons in its valence shell
D. it follows the octet rule, having 8 electrons in its valence shell
. Ionic compounds cannot interact with covalently bonded compounds. True False
False
All isotopes are radioactive. True False
False
. Ammonia, a component of many household cleaners, has a low H+ concentration and so has a high pH. True False
True
. The shapes of molecules are often important in their function. True False
True
Loss of water molecules from a person's skin during perspiration helps lower body heat because excess heat is directed to break hydrogen bonds between water molecules. True False
True