CHEM 162 FINAL REVIEW QUESTIONS
AND ANSWERS
1) What is the pH of a solution of 0.020 M HNO3? - Correct Answers -
2.) Which of the following is the strongest acid?
a) H2SeO3 b) H2SeO c) H2SeO2 d) all the same e) none - Correct Answers -a)
H2SeO3
-the more oxygens, the stronger the acid
3.) What is the pH of a 0.0050 M solution of sodium cyanide? (HCN Ka = 6.2 x 10-10)
a) 7.5 b) 10.4 c) 11.8 d) 8.2 e) none - Correct Answers -b) 10.4
6.) Write a balanced chemical equation for the complete combustion of C6H6 (benzene)
(in the presence of
excess oxygen) and pick the right molar amounts of CO2 and H2O. - Correct Answers -
D) 12 and 6
2C6H6(l) + 15O2(g) 12CO2(g) + 6H2O(g)
7.) Balance the reaction
Sn + NO3^- → SnO^2 + NO occurring in an acidic solution. The correct
coefficient for SnO^2 is? - Correct Answers -c) 3
8.) For the problem above what is the correct coefficient for NO3^- is? - Correct
Answers -b) 4
5.) Calculate the molar solubility of lead iodide in water from its Ksp at 25 °C. (Ksp = 7.9
x 10-9
)
a) 7.9 x 10-9
b) 2.0 x 10-9
c) 1.3 x 10-3
d) 5.3 x 10-3
e) none - Correct Answers -c) 1.3 x 10^-3
9.) Is an isotope and an allotropy the same thing?
, a) yes b) no c) sometimes d) not enough info e) none of the above - Correct Answers -
b) NO
--isotope--each isotope of a given element has a different mass number.
--allotropy=the property of some chemical elements to exist in two or more different
forms, in the same physical state, known as allotropes of these elements.
10.) Complete the following nuclear reaction and pick the correct product; ^220Rn -->
^4He + ??? - Correct Answers -c) ^ 216Po
^216Po
84
11.) Which is the correct symbol for a bismuth-211 atom that has decayed by beta
emission?
a) 211Pb b) 212Bi c) 212Pb d) 210Tl e) none - Correct Answers -e) none
211Bi -->
0/-1 e^- + 211Po
13.) Although lead-164 has two magic numbers, 82 protons and 82 neutrons, this
isotope is unknown. Lead-
208, however, is known and stable. Which statement best accounts for the
nonexistence of lead-164?
a) not enough neutrons
b) too many protons
c) Atomic number is more than bismuth
d) too many neutrons
e) neutron-proton ratio is to high - Correct Answers -a) not enough neutrons
The neutron-to-proton ratio of lead-164 is too low. It has too few neutrons for the
number of protons
in the nucleus.
12.) What percentage of cesium chloride made from cesium-137 (t1/2= 30 yr; beta
emitter) remains after
150 yr? - Correct Answers -3.1 %
simple way to answer;
if you can divide the amount of years by the half life, then put that as a exponent of
(1/2).
-ie 1/2^(total years/half life)
-ie..5 half life x 30yrs = 150 yrs--> (1/2)^5
= 1/32 = 0.03125
14.) Adding a catalyst to a reaction at equilibrium will shift it...
a) to the right b) to the left c) lower energy of the products d) not at all e) none
from lecture and book and midterm - Correct Answers -d) not at all
AND ANSWERS
1) What is the pH of a solution of 0.020 M HNO3? - Correct Answers -
2.) Which of the following is the strongest acid?
a) H2SeO3 b) H2SeO c) H2SeO2 d) all the same e) none - Correct Answers -a)
H2SeO3
-the more oxygens, the stronger the acid
3.) What is the pH of a 0.0050 M solution of sodium cyanide? (HCN Ka = 6.2 x 10-10)
a) 7.5 b) 10.4 c) 11.8 d) 8.2 e) none - Correct Answers -b) 10.4
6.) Write a balanced chemical equation for the complete combustion of C6H6 (benzene)
(in the presence of
excess oxygen) and pick the right molar amounts of CO2 and H2O. - Correct Answers -
D) 12 and 6
2C6H6(l) + 15O2(g) 12CO2(g) + 6H2O(g)
7.) Balance the reaction
Sn + NO3^- → SnO^2 + NO occurring in an acidic solution. The correct
coefficient for SnO^2 is? - Correct Answers -c) 3
8.) For the problem above what is the correct coefficient for NO3^- is? - Correct
Answers -b) 4
5.) Calculate the molar solubility of lead iodide in water from its Ksp at 25 °C. (Ksp = 7.9
x 10-9
)
a) 7.9 x 10-9
b) 2.0 x 10-9
c) 1.3 x 10-3
d) 5.3 x 10-3
e) none - Correct Answers -c) 1.3 x 10^-3
9.) Is an isotope and an allotropy the same thing?
, a) yes b) no c) sometimes d) not enough info e) none of the above - Correct Answers -
b) NO
--isotope--each isotope of a given element has a different mass number.
--allotropy=the property of some chemical elements to exist in two or more different
forms, in the same physical state, known as allotropes of these elements.
10.) Complete the following nuclear reaction and pick the correct product; ^220Rn -->
^4He + ??? - Correct Answers -c) ^ 216Po
^216Po
84
11.) Which is the correct symbol for a bismuth-211 atom that has decayed by beta
emission?
a) 211Pb b) 212Bi c) 212Pb d) 210Tl e) none - Correct Answers -e) none
211Bi -->
0/-1 e^- + 211Po
13.) Although lead-164 has two magic numbers, 82 protons and 82 neutrons, this
isotope is unknown. Lead-
208, however, is known and stable. Which statement best accounts for the
nonexistence of lead-164?
a) not enough neutrons
b) too many protons
c) Atomic number is more than bismuth
d) too many neutrons
e) neutron-proton ratio is to high - Correct Answers -a) not enough neutrons
The neutron-to-proton ratio of lead-164 is too low. It has too few neutrons for the
number of protons
in the nucleus.
12.) What percentage of cesium chloride made from cesium-137 (t1/2= 30 yr; beta
emitter) remains after
150 yr? - Correct Answers -3.1 %
simple way to answer;
if you can divide the amount of years by the half life, then put that as a exponent of
(1/2).
-ie 1/2^(total years/half life)
-ie..5 half life x 30yrs = 150 yrs--> (1/2)^5
= 1/32 = 0.03125
14.) Adding a catalyst to a reaction at equilibrium will shift it...
a) to the right b) to the left c) lower energy of the products d) not at all e) none
from lecture and book and midterm - Correct Answers -d) not at all
