chapter 2
33) Relative to a pH of 6, a pH of 4 has a ________.
B) 100 times higher H+ concentration
17) Sulfur has an atomic number of 16. How many covalent bonds can sulfur form?
B) 2
37) A fossil was found and determined by radiometric dating to be 11,400 years old. What is the ratio of carbon-14 to carbon-12 in this fossil compared to its environment?
B) 25%
A solution which resists pH changes is referred to as:
buffer
20) Adjacent water molecules are joined by ________ bonds.
hydrogen
18) The hydrogen and oxygen atoms of a water molecule are held together by ________ bonds.
C) covalent
35) When a base is added to a buffered solution, the buffer will ________.
C) donate H+ ions
27) Sweating cools your body by ________.
C) evaporative cooling
4) Which of the following elements, essential to life, is a trace element?
C) iodine
13) An atom with an electrical charge is a(n) ________.
C) ion
2) ________ is an example of an element.
Carbon
How many oxygen atoms are in the products of the following reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O
D) 24
8) Beryllium's atomic mass is 9, and its atomic number is 4. How many neutrons are found in a beryllium atom?
D) 5
24) Human body cells are approximately ________ water.
D) 70-95%
) In a solution, if the hydroxide ion concentration exceeds the hydrogen ion concentration the solution is considered to be:
A base
9) 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
36) Which of the following is NOT a potential impact of ocean acidification?
A) Decreasing H+ concentrations
34) What name is given to substances that resist changes in pH?
A) buffers
16) What name is given to bonds that involve the sharing of electrons?
A) covalent
14) The bond between oppositely charged ions is a(n) ________ bond.
A) ionic
28) As water freezes, ________.
A) its molecules move farther apart
5) In order to have a positive charge, an atom must have ________.
A) more protons than electrons
7) An atom's ________ are found in its nucleus.
A) neutrons and protons
11) Isotopes of an element have the same number of ________ and different numbers of ________.
A) protons... neutrons
What are the reactant(s) in the following chemical reaction? C6H12O6 + 6 H2O + 6 O2 → 6 CO2 + 12 H2O
B) C6H12O6, H2O, and O2
26) Why (if you are careful) are you able to float a needle on the surface of water?
B) The surface tension that is a result of water's cohesive properties makes this possible.
10) The way Earth moves about the sun is most like ________.
B) an electron moving around the nucleus of an atom
3) The four most common elements found in living organisms are ________.
B) carbon, oxygen, nitrogen, and hydrogen
25) The tendency of molecules of the same kind to stick together is called ________.
B) cohesion
21) Adjacent water molecules are connected by the ________.
B) electrical attraction between the hydrogen of one water molecule and the oxygen of another water molecule
In the following reaction, what type of bond is holding the two atoms together? K+Cl → K+ + Cl− → KCl
B) ionic
32) The lower the pH of a solution, the ________.
B) more acidic the solution
6) All atoms of an element have the same number of ________.
B) protons
29) Sugar dissolves when stirred into water. The sugar is the ________, the water is the ________, and the sweetened water is the ________.
B) solute... solvent... solution
30) Which of the following is an acid?
C) HCl
19) Why is water considered a polar molecule?
C) The oxygen end of the molecule has a slight negative charge, and the hydrogen end has a slight positive charge.
1) How can radiation be controlled and safely used in medicine?
D) Apply radiation to specific parts of the body at controlled doses.
12) How do radioactive isotopes differ from isotopes?
D) Radioactive isotopes are unstable; isotopes are stable.
31) A base ________.
D) removes H+ ions from a solution
40) When water is mixed with a salt in a beaker, the salt would be considered: A. The solvent B. The solute C. Solution D. Buffer E. Ion
the solute
