Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Aluminum reacts with a certain nonmetallic element to form a compound with the general formula
Al2 X3 . Element X must be from Group __________ of the Periodic Table of Elements.
1)
2) Which of the following are weak acids?
A) HI, HF
B) HI, HNO3 , HBr
2)
3) Which formula/name pair is incorrect?
magnesium nitrate
A) Mg(NO3 )2
manganese(II) nitrite
B) Mn(NO2 )2
3)
A) 5A
B) 3A
C) 7A
D) 4A
E) 6A
C) HF
D) HF, HBr
E) none of the above
C) Mg(MnO4 )2 magnesium permanganate
D) Mn(NO3 )2
E) Mg3N2
manganese(II) nitrate
magnesium nitrite
4) The formula weight of ammonium sulfate ((NH4 )2 SO4), rounded to the nearest integer, is
__________ amu.
A) 116
B) 264
C) 100
D) 132
4)
E) 118
5) What volume (mL) of a concentrated solution of sodium hydroxide (6.00 M) must be diluted to
200.0 mL to make a 0.880 M solution of sodium hydroxide?
A) 29.3
B) 50.0
C) 176
D) 26.4
E) 2.64
5)
6) There are __________ atoms of oxygen are in 300 molecules of CH3CO2H.
6)
A) 3.01 × 1024
B) 3.61 × 1026
C) 600
D) 300
E) 1.80 × 1026
7) The charge on the iron ion in the salt Fe2 O3 is __________.
A) +2
B) +1
8) Which species below is the nitride ion?
A) Na +
B) NH4 +
C) -5
D) -6
E) +3
C) NO3 -
D) NO2 -
E) N 3-
D) 7.743
E) 4.032
9) The mass % of H in methane (CH4) is __________.
A) 25.13
B) 74.87
7)
8)
9)
C) 92.26
1
10) Which metal is not required to have its charge specified in the names of ionic compounds it forms?
A) Fe
B) Pb
C) Cu
D) Ca
E) Mn
10)
11) What is the formula for perchloric acid?
A) HCl
B) HClO
11)
C) HClO3
D) HClO4
E) HClO2
12) Which of the following is an oxidation-reduction reaction?
2HNO3 (aq) + CaCO3 (s)
A) H2 CO3 (aq) + Ca(NO3 )2 (aq)
BaSO4 (s) + 2NaC2 H3O2 (aq)
B) Ba(C2H3 O2 )2 (aq) + Na2 SO4 (aq)
C) Cu (s) + 2AgNO3 (aq)
D) AgNO3 (aq) + HCl (aq)
E) HCl (aq) + NaOH (aq)
12)
2Ag (s) + Cu(NO3 )2 (aq)
AgCl (s) + HNO3 (aq)
H2O (l) + NaCl (aq)
13) The net ionic equation for the reaction between aqueous nitric acid and aqueous sodium hydroxide
is __________.
2H2O (l) + NO3- (aq)
A) H+ (aq) + HNO3 (aq) + 2OH- (aq)
B) H+ (aq) + OH- (aq)
C) HNO3 (aq) + NaOH (aq)
13)
H2O (l)
NaNO3 (aq) + H2 O (l)
H2O (l) + Na+ (aq)
D) H+ (aq) + Na+ (aq) +OH- (aq)
E) HNO3 (aq) + OH- (aq)
NO3- (aq) + H2 O (l)
14) When the following equation is balanced, the coefficient of Al2 O3 is __________.
Al2 O3 (s) + C (s) + Cl2 (g)
A) 4
14)
AlCl3 (s) + CO (g)
B) 5
C) 3
D) 2
15) Which combination will produce a precipitate?
A) AgNO3 (aq) and Ca(C2H3 O2 )2 (aq)
E) 1
15)
B) NaOH (aq) and HCl (aq)
C) NaOH (aq) and KCl (aq)
D) KOH (aq) and Mg(NO3)2 (aq)
E) NaC2 H3O2 (aq) and HCl (aq)
16) The correct name for CCl4 is __________.
16)
A) carbon tetrachloride
B) carbon tetrachlorate
C) carbon chlorate
D) carbon chloride
E) carbon perchlorate
2
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
17) 2.74 g of Al2 (SO4)3 x
x
x
x
x
x
x
x
x
= 5.78 x 10 22 O atoms
3.74 g of Al2 (SO4)3 x
= 7.90 x 10 22 O atoms
4.74 g of Al2 (SO4)3 x
= 1.00 x 10 23 O atoms
5.74 g of Al2 (SO4)3 x
= 1.21 x 10 23 O atoms
3
18)
1.
A compound was found to contain 90.6% lead (Pb) and 9.4% oxygen. What is the empirical formula for
this compound..
90.6 g Pb x
9.4 mole O x
= 0.437258 moles Pb/ 0.437258 =1 x 3 = 3
= 0.5875 moles O /0.437258 = 1.34 x 3 = 4
Answer : Pb3O4
2.
A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass.
What is the empirical formula of the compound?
85.7 g C x
14.3 g H
= 7.14 moles C / 7.14 = 1
= 14.18 moles H / 7.14 = 2
Answer CH2
3.
A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass.
What is the empirical formula of the compound?
80.0 g C x
= 6.666 mole C / 6.666 = 1
20 g H x
= 19.84 mole H / 6.666 = 2.97
Answer CH3
4
4. What is the empirical formula of an oxide of nitrogen whose composition is 25.94%
nitrogen and the rest oxygen?
25.94 g N x
74.06 g O x
= 1.851 mol N / 1.851 = 1 x2 = 2
4.628 mole O/ 1.851 = 2.5 x 2 = 5
Answer N2O5
5