Download 1. Classify the following reaction. Sb2O3 + 3 Fe

1. Classify the following reaction.
Sb2O3
+ 3 Fe →
2 Sb +
3 FeO
a) Combination reaction
b) Decomposition reaction
c) Neutralization reaction
d) Single-replacement reaction
e) Double-replacement reaction
2. Which of the following reactions is a Redox reaction? All are double-replacement rxns
except b. Rxns c and e are also called neutralization reactions.
a) HCl (aq)
+ AgNO3 (aq)
+ 3 H2
b) WO3
c) Ba(OH)2 (aq)
d) BaBr2 (aq)
e) NaOH
+
→
→
Pb(NO3)2 (aq)
HBr
→
AgCl (s)
W + 3 H2O
+ H2SO4 (aq)
+
HNO3 (aq) +
→
BaSO4 (s) +
→
2 H2O (l)
Ba(NO3)2 (aq) +
PbBr2 (s)
H2O + NaBr
3. Which of the following compounds is soluble? The solubility rules are listed on page 8.
a) Hg2Cl2
b) PbSO4
c) K2S
d) Fe(OH)2
e) Mg3(PO4)2
4. When an aqueous solution of potassium sulfate is mixed with an aqueous solution of lead
nitrate a precipitate is formed (consult the solubility rules on page 8). Which are the
spectator ions for this reaction? K2SO4 (aq) + Pb(NO3)2 (aq) → 2 KNO3 (aq) + PbSO4 (s)
net ionic eqn: Pb2+ + SO42- → PbSO4
a) none are spectator ions
b) Pb2+ and NO3c) Pb2+ and SO42d) K+ and SO42e) K+ and NO35. What is the oxidation number for sulfur in Na2SO3?
a) -2
b) -4
c) +6
d) +4
2(+1) + S + 3(-2) = 0
S = +4
e) +2
6. Balance the following equation. What is the sum of the coefficients of the reactants and
products?
4 NH3
+
5 O2
→
4 NO
+
6 H2O
a) 12
b) 15
c) 19
d) 20
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e) 22
7. Which of the following statements is NOT correct for the reaction of sodium hydroxide with
sulfuric acid?
2 NaOH (aq)
a)
b)
c)
d)
e)
+
H2SO4 (aq) →
Na2SO4 (aq) + 2 H2O (l)
The above equation is properly balanced.
A neutralization reaction occurred.
The net ionic equation is H+ + OH- → H2O
This is a double-replacement reaction.
Hydrogen ions and hydroxide ions are spectator ions.
8. Which of the following statements correctly describes what happens when a solution of
sodium bromide is mixed with a solution of iodine? 2 NaBr (aq) + I2 (aq) →
a)
b)
c)
d)
e)
No reaction occurs.
NaI (aq) is formed.
A redox reaction occurs.
Sodium iodide precipitates
The reaction produces Br2.
Recall:
Reactivity of halogens
F > Cl > Br > I
I2 cannot replace Br-
9. Identify the oxidizing agent in the following oxidation-reduction reaction.
(+3)(-2)
(0)
(+3)(-2)
(0)
Fe2O3
+
2 Al
→
Al2O3 +
2 Fe
a) Fe3+
b) O2-
d) Al3+
c) Al
e) Fe
10. Which of the following reactions is an oxidation?
O
║
a) CH3 – C – OH
O
║
CH3 – C – H
→
b) CH2 ═ CH2
→
H–C≡C–H
O
║
c) CH3 – C – H
→
CH3 – CH2 – OH
d) CH3 – CH2 -OH
e) CH2 ═ CH2
→
→
CH3 – CH3
CH3 – CH3
2
Loss of hydrogen atoms = oxidation
11. How many grams of NaBO3 are in 4.65 moles?
(Atomic weights: B = 10.81, O = 16.00, Na = 22.99)
a) 74.4
81.8 g
1 mol
b) 112
x
c) 223
Fw = 81.8
d) 380
e) 450
4.65 mol
12. To three significant figures, what is the percent of calcium ions in Ca3(PO4)2?
(Atomic weights: Ca = 40.08, O = 16.00, P = 30.97)
a) 12.9
b) 25.8
c) 38.8
d) 54.5
3 x Ca2+
Ca3(PO4)2
Fw Ca3(PO4)2 310.18
e) 61.2
3 x 40.08 x 100
310.18
13. A hospital patient is given a solution containing 9.00 x 10-9 g of iodine-131 (isotopic
weight: 131). How many atoms of iodine are present? Avogadro’s Number = 6.02 x 1023
a) 4.14 x 1015
b) 4.14 x 1013
c) 6.68 x 1017 d) 1.36 x 109
e) 1.36 x 108
9.00 x 10-9 g x 1 mol x 6.02 x 1023 atoms
131 g
1 mol
14. How many moles of sulfur atoms are in 78.45 g of Al2(SO4)3?
(Atomic weights: Al = 26.98, O = 16.00, S = 32.06)
a) 0.2300
b) 0.6879
Fw Al2(SO4)3 = 342.14
c) 0.9200
d) 2.752
78.45 g of Al2(SO4)3 x
3
1 mol
342.14 g
e) 5.504
x
3 S atoms
1 mol Al2(SO4)3
15. When marijuana passes through the human body, one of the products formed contains
76.4% C, 9.2% H and 14.5% O. What is the empirical formula of the compound?
(Atomic weights: C = 12.01, H = 1.008, O = 16.00)
b) CH4O
a) CHO
c) C5H8O
d) C7H10O
e) C8H12O2
C 76.4g x 1 mol = 6.361 mol
12.01 g
6.361 = 7.0
0.906
H
9.2g
9.13 = 10.1
0.906
O
14.5g x 1mol = 0.906 mol
16.00g
x
1 mol = 9.13 mol
1.008 g
0.906 = 1
0.906
16. Which of the following setups is correct to calculate the number of grams of KClO3
produced from the reaction of 0.150 moles of Cl2. (Atomic weights: K = 39.1, Cl = 35.45,
O = 16.00)
3 Cl2 + 6 KOH → 5 KCl + KClO3 + 3 H2O
a) 0.150 moles Cl2 x 1 mole KClO3
3 moles Cl2
x
b) 0.150 moles Cl2 x 3 moles Cl2
1 mole KClO3
x
c) 0.150 moles Cl2 x 1 mole KClO3
3 moles Cl2
x
x
d) 0.150 moles Cl2 x 3 moles Cl2
1 mole KClO3
122.6 g
1 mole KClO3
122.6 g
1 mole KClO3
1 mole KClO3
122.6 g
1 mole KClO3
122.6 g
17. 1.0 moles Fe2S3 are reacted with 2.0 moles H2O and 3.0 moles O2 according to the
following reaction. Which is the limiting reagent?
2 Fe2S3 + 6 H2O + 3 O2 → 4 Fe(OH)3 + 6 S
a) Fe2S3
b) H2O
1.0 mol Fe2S3 = 1
2
2
c) O2
d) Fe(OH)3
2.0 moles H2O = 1
6
3
4
e) S
3.0 moles O2 =
3
1
18. The reaction of 6.8 g of H2S with excess SO2 according to the following reaction yields
8.2 g of S. What is the percent yield? (Atomic weights: H = 1.008, S = 32.06, O = 16.00)
Mw H2S = 34.08
2 H2S + SO2 → 3 S + 2 H2O
a) 85%
b) 87%
c) 82%
d) 90%
6.8 g H2S x 1 mol H2S x 3 mol S
x
34.08 g H2S
2 mol H2S
8.2 g S (actual yield)
9.6 g S (theoretical yield)
x 100
e) 78%
32.06 g S = 9.60 g S theoretical yield
1 mol S
= 85 %
19. What amount of heat energy (kJ) is released in the decomposition of 0.500 moles of
hydrogen peroxide to water and oxygen? ∆H = -196 kJ
2 H2O2 (l) → 2 H2O (l) + O2 (g)
a) 49.0
b) 98.0
0.500 moles H2O2 x
c) 19.6
196 kJ
2 mol H2O2
d) 392
e) 196
= 49.0 kJ
20. What is the density (g/L) of nitrogen at STP? (Atomic weight: N = 14.01)
a) 0.312
28.02 g N2 x
1 mol
b) 0.800
1 mol
22.4 L
c) 1.25
d) 0.625
e) 1.60
= 1.25 g/L
21. Which of the following statements is NOT correct?
a) Pressure is force per unit area.
b) Real gases behave according to the kinetic molecule theory only at high
temperatures and low pressures.
c) Viscosity and surface tension of liquids depend on the strength of
intermolecular forces.
d) A dynamic equilibrium exists between a liquid and gas at its boiling point.
e) Pressure has no effect on boiling points. FALSE
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22. Which conversion of units for pressure is correct? 760 mm Hg = 760 torr = 1 atm
a) 1.14 x 103 cm Hg = 1.50 atm
b) 228 mm Hg = 0.351 atm
c) 430 torr = 430 cm Hg
d) 152 torr = 0.217 atm
e) 0.0600 atm = 45.6 mm Hg
23. The pressure on a 14.4 L sample of oxygen at 748 mm Hg is increased to 1.31 x 103 mm Hg
at constant temperature. What will be the new volume in L?
a) 25.2
b) 17.5
V1 x P1 = V2 x P2
c) 12.4
d) 8.22
e) 6.30
14.4 L x 748 mm Hg = V2
x 1.31 x 103 mm Hg
V2 = 8.22 L
24. A 2.00 L sample of air at –23oC is warmed to 100oC. What is the new volume (L) if the
pressure remains constant?
a) 2.30
b) 3.67
V1 = V2
T1
T2
c) 2.54
2.00 L
=
(-23 + 273) K
V2
d) 3.33
e) 2.98
V2
(100 + 273) K
= 2.98 L
25. A high altitude balloon is filled with 1.41 x 104 L of helium at 294 K and 745 torr. What is
the volume (L) of the balloon at 20 Km where the temperature is 225 K and 63.1 torr?
a) 1.10 x 105
V1P1
T1
=
V2P2
T2
b) 1.27 x 105
c) 1.58 x 105
d) 1.89 x 105
1.41 x 104 L x 745 torr
294 K
V2
6
= V2 x 63.1 torr
225 K
=
1.27 x 105 L
e) 2.18 x 105
26. Assume 453.6 g of dry ice (solid CO2) is placed in an evacuated 50.0 L closed tank. What
will be the pressure in the tank in atmospheres at a temperature of 45oC? Assume that all
the CO2 has been converted into gas. (Atomic weights: C = 12.01, O = 16.00; the
universal gas constant is 0.0821 L atm mole-1 K-1 )
a) 7.25
b) 6.10
Mw CO2 = 44.01
c) 5.38
PV
=
d) 10.8
e) 9.15
nRT
P x 50.0 L = (453.6 g x 1 mol/ 44.01 g) x 0.0821 L atm mole-1 K-1 x (45 + 273)K
P = 5.38 atm
27. Which of the following is NOT possible?
a)
b)
c)
d)
e)
Water can boil at room temperature.
The boiling of water on mountain tops is below 100oC.
In a pressure cooker, water boils above 100oC.
Water has a lower heat of vaporization than CH4.
Water has a higher surface tension than gasoline.
28. Which of the following molecules has the lowest boiling point?
d>b>e>a>c
a) CH3 – CH2 – CH2 – CH3
b) CH3 – CH2 – CH2 – OH
CH3
‫׀‬
c) CH3 – CH – CH3
d) HO – CH2 – CH2 – OH
O
║
e) CH3 – C – CH3
29. In which of the pure compounds in Question 28 would dipole-dipole forces be observed?
Hydrogen-bonding possible only for b and d but molecules
a) b, d and e
b, d, and e are all polar and have dipole moments.
b) a and c
Molecules a and c are nonpolar and exhibit only London forces.
c) only e
d) all of them
e) none of them
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30. Oxygen toxicity occurs if a partial pressure of oxygen of about 1 atm is breathed for too
long. At what total pressure of compressed air delivered to a diver can toxicity occur?
Air is 20 % oxygen.
a) 1 atm
b) 2 atm
c) 3 atm
d) 4 atm
e) 5 atm
0.20 x ( ? atm compressed air) = 1 atm O2
? atm compressed air = 5 atm
Solubility Rules of Common Ionic Compounds
1. All ionic compounds of lithium, sodium, potassium, rubidium, cesium, and
ammonium ions are soluble.
2. All nitrates, chlorates, and perchlorates are soluble.
3. The chlorides, bromides, and iodides of most metals are soluble. Principal exceptions
are those of lead, silver, and mercury (I).
4. All sulfates are soluble except those of strontium, barium, lead, and mercury (I).
5. All carbonates, chromates, and phosphates are insoluble except those of lithium,
sodium, potassium, rubidium, cesium, and ammonium.
6. The hydroxides of lithium, sodium, potassium, rubidium, and cesium ions are soluble.
The hydroxides of calcium, strontium, and barium are moderately soluble. The rest
of the hydroxides are insoluble.
7. The sulfides of all metals are insoluble except those of lithium, sodium, potassium,
rubidium, cesium, and ammonium.
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