Biiology SC002 Chapter 2

10) Isotopes of an element have the same number of ______ and different numbers of ______. A) protons... neutrons B) protons... electrons C) neutrons... protons D) electrons... protons

A

15) The bond between oppositely charged ions is a(n) ______ bond. A) ionic B) polar C) hydrogen D) covalent

A

17) What name is given to bonds that involve the sharing of electrons? A) covalent B) hydrogen C) ionic D) polar

A

29) As water freezes, ______. A) its molecules move farther apart B) it cools the surrounding environment C) its hydrogen bonds break apart D) it loses its polarity

A

35) What name is given to substances that resist changes in pH? A) buffers B) sugars C) salts D) bases

A

4) An atom with a positive charge has ______. A) more protons than electrons B) more electrons than protons C) more neutrons than protons D) more protons than neutrons

A

6) An atom's ______ are found in its nucleus. A) neutrons and protons B) protons only C) neutrons and electrons D) electrons, protons, and neutrons

A

8) An uncharged atom of gold has an atomic number of 79 and an atomic mass of 197. This atom has ______ protons, ______ neutrons, and ______ electrons. A) 79... 118... 79 B) 118... 79... 118 C) 118... 276... 118 D) 79... 34... 79

A

1) ______ is an example of an element. A) Water B) Carbon C) Glucose D) Salt

B

16) In the following reaction, what type of bond is holding the two atoms together? K + Cl → K+ + Cl- → KCl A) hydrophilic B) ionic C) hydrophobic D) covalent

B

18) Sulfur has an atomic number of 16. How many covalent bonds can sulfur form? A) 1 B) 2 C) 4 D) 0

B

2) The four most common elements found in living things are A) nitrogen, oxygen, phosphorus, and carbon. B) carbon, oxygen, nitrogen, and hydrogen. C) carbon, oxygen, potassium, and calcium. D) oxygen, calcium, hydrogen, and carbon.

B

22) Adjacent water molecules are connected by the ______. A) sharing of electrons between the hydrogen of one water molecule and the oxygen of another water molecule B) electrical attraction between the hydrogen of one water molecule and the oxygen of another water molecule C) sharing of electrons between adjacent oxygen molecules D) electrical attraction between the hydrogens of adjacent water molecules

B

24) What are the reactant(s) in the following chemical reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O A) CO2 and H2O B) C6H12O6, H2O, and O2 C) O2 only D) C6H12O6, H2O, O2, CO2, and H2O

B

26) The tendency of molecules of the same kind to stick together is called ______. A) bonding B) cohesion C) polarity D) adhesion

B

27) Why (if you are careful) are you able to float a needle on the surface of water? A) Water has adhesive properties. B) The surface tension that is a result of water's cohesive properties makes this possible. C) The covalent bonds that hold a water molecule together are responsible for this ability. D) A single needle is less dense than water.

B

30) Sugar dissolves when stirred into water. The sugar is the ______, the water is the ______, and the sweetened water is the ______. A) solution... solvent... solute B) solute... solvent... solution C) solvent... solute... solution D) solution... solute... solvent

B

33) The lower the pH of a solution, the ______. A) greater the number of oxygen atoms B) more acidic the solution C) less toxic the solution D) higher the OH— concentration

B

34) Relative to a pH of 6, a pH of 4 has a ______. A) 200 times higher H+ concentration B) 100 times higher H+ concentration C) 20 times higher H+ concentration D) 100 times lower H+ concentration

B

37) People have long speculated about whether life exists on Mars. Scientists have evidence that on Mars, ______. A) microbial life exists B) liquid water has existed in the past C) the only water present has always been frozen in the polar ice caps D) water is found only in the form of water vapor

B

5) All atoms of an element have the same number of ______. A) protons plus neutrons B) protons C) electrons D) neutrons

B

9) The way Earth moves about the sun is most like ______. A) a neutron and electron moving around a proton B) an electron moving around the nucleus of an atom C) a proton moving about an electron D) a neutron moving about a proton

B

The last few miles of the marathon are the most difficult for Heather. Her hair is plastered to her head, sweat clings to her arms, and her legs feel as if they had nothing left. Heather grabs a cup of ice water. The ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. Then a breeze kicks up and she finally feels some coolness against her skin. Drops of sweat, once clinging to her forehead, now spill down, and Heather feels a stinging as the sweat flows into her eyes. 41) Sweat on Heather's forehead and arms formed drops because of the ______. A) high salt content of sweat B) cohesive nature of water C) ability of water to moderate heat D) high evaporative cooling effect of water

B

13) Nitrogen has an atomic number of 7; therefore, it has ______ electrons in its outermost electron shell. A) 10 B) 18 C) 5 D) 2

C

14) An atom with an electrical charge is a(n) ______. A) isotope B) molecule C) ion D) compound

C

19) The hydrogens and oxygen of a water molecule are held together by ______ bonds. A) electron B) hydrogen C) covalent D) osmotic

C

20) Why is water considered a polar molecule? A) The oxygen is found between the two hydrogens. B) The oxygen atom attracts the hydrogen atoms. C) The oxygen end of the molecule has a slight negative charge, and the hydrogen end has a slight positive charge. D) Both hydrogens are at one end of the molecule, and oxygen is at the other end.

C

28) Sweating cools your body by ______. A) cohesion B) radiation C) evaporative cooling D) hydrogen bonding

C

3) Which of the following elements, essential to life, is a trace element? A) phosphorus B) carbon C) iodine D) calcium

C

31) Which of the following is an acid? A) NaOH B) NaCl C) HCl D) CH4

C

36) When a base is added to a buffered solution, the buffer will ______. A) donate OH- ions B) accept water molecules C) donate H+ ions D) form covalent bonds with the base

C

The last few miles of the marathon are the most difficult for Heather. Her hair is plastered to her head, sweat clings to her arms, and her legs feel as if they had nothing left. Heather grabs a cup of ice water. The ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. Then a breeze kicks up and she finally feels some coolness against her skin. Drops of sweat, once clinging to her forehead, now spill down, and Heather feels a stinging as the sweat flows into her eyes. 42) Which of the following is the most likely reason why the ice struck Heather's nose when she took a drink? A) Water can store large amounts of heat. B) Water can moderate temperatures through evaporative cooling. C) The density of water decreases when it freezes. D) Water has a cohesive nature.

C

11) How do radioactive isotopes differ from isotopes? A) Radioactive isotopes have more neutrons than do isotopes. B) Radioactive isotopes are stable; isotopes are unstable. C) Radioactive isotopes have fewer neutrons than do isotopes. D) Radioactive isotopes are unstable; isotopes are stable.

D

12) The second electron shell of an atom can hold a maximum of ______ electron(s). A) 1 B) 2 C) 6 D) 8

D

21) Adjacent water molecules are joined by ______ bonds. A) covalent only B) ionic C) polar and covalent D) hydrogen

D

23) How many oxygen atoms are in the products of the following reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O A) 18 B) 6 C) 12 D) 24

D

25) Human body cells are approximately ______ water. A) 95—99% B) 25—35% C) 50—55% D) 70—95%

D

32) A base ______. A) removes H2O molecules from a solution B) decreases the pH of a solution C) removes OH— ions from a solution D) removes H+ ions from a solution

D

7) Beryllium's atomic mass is 9 and its atomic number is 4. How many neutrons are found in a beryllium atom? A) 9 B) 13 C) 4 D) 5

D P+N=M M-P=N Atomic Number = Protons, Mass+Protons+Neutrons