CHEM 1211K
Test II
MULTIPLE CHOICE. (3 points each)
1) The charge on the manganese in the salt MnF3 is __________.
A) +1
B) +2
C) -2
2)
3)
4)
5)
D) +3
Which formula/name pair is incorrect?
A) FeS iron(II) sulfide
C) FeSO3 iron(II) sulfite
E) Fe2(SO4)3 iron(III) sulfide
B) FeSO4
iron(II) sulfate
D) Fe2(SO3)3 iron(III) sulfite
The name of PCl3 is __________.
A) monophosphorous trichloride
C) trichloro potassium
E) potassium chloride
B) phosphorus trichloride
D) phosphorous(III) chloride
Which one of the following is the formula of perchloric acid?
A) HClO
B) HClO4
C) HClO3
D) HCl
E) -1
E) HClO2
When the following equation is balanced, the coefficient of water is __________.
N2O5 (g) + H2O (l) Æ HNO3 (aq)
A) 3
B) 2
C) 1
D) 4
E) 5
6)
Of the reactions below, which one is a decomposition reaction?
A) 2CH4 + 4O2 Æ 2CO2 + 4H2O
B) NH4Cl Æ NH3 + HCl
C) 2N2 + 3H2 Æ 2NH3
D) Cd(NO3)2 + Na2S Æ CdS + 2NaNO3
E) 2Mg + O2 Æ 2MgO
7)
The formula weight of ammonium sulfate ((NH4)2SO4 is __________ amu.
A) 132
B) 116
C) 118
D) 100
E) 264
The mass % of Al in aluminum sulfate, Al2(SO4)3, is __________.
A) 15.77
B) 35.94
C) 45.70
E) 21.93
8)
9)
D) 7.886
How many moles of carbon dioxide are there in 52.06 g of carbon dioxide?
A) 3.134 x 1025
B) 0.8452
C) 1.183
D) 8.648 x 1023
E) 6.022 x 1023
10) A sulfur oxide is 50.0% by mass sulfur. This molecular formula could be __________.
A) SO3
B) SO2
C) SO
D) S2O
E) none of these
11) The combustion of propane (C3H8) in the presence of excess oxygen yields CO2 and H2O:
C3H8 (g) + 5O2 (g) Æ 3CO2 (g) + 4H2O (g)
when 2.5 mol of O2 are consumed in their reaction, __________ mol of CO2 are produced.
A) 3.0
B) 2.5
C) 5.0
D) 6.0
E) 1.5
12) Pentacarbonyliron (Fe(CO)5) reacts with phosphorous trifluoride (PF3) and hydrogen, releasing carbon
monoxide:
Fe(CO)5 + 2PF3 + H2 Æ Fe(CO)2(PF3)2(H)2 + 3CO
The reaction of 5.0 mol of Fe(CO)5, 8.0 mol of PF3 and 6.0 mol of H2 will release __________ mol of CO.
A) 5.0
B) 24
C) 15
D) 12
E) 6.0
13) Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide:
4Al (s) + 3O2 (g) Æ 2Al2O3 (s)
In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O2 produced 3.5 g of Al2O3. The %
yield of the reaction is __________.
A) 37
B) 26
C) 74
D) 47
E) 66
14) The net ionic equation for the reaction between aqueous solutions of HCl and KOH is __________.
A) HF + KOH Æ H2O + K+ + FB) HF + OH- Æ H2O + FC) H+ + F- + K+ + OH- Æ H2O + K+ + FD) H+ + OH- Æ H2O
E) HF + K+ + OH- Æ H2O + KF
15) Which one of the following compounds is insoluble in water?
A) FeCl3
B) ZnS
C) K2O
D) AgNO3
E) NaCl
16) Which one of the following is a weak acid?
B) HCl
A) HClO4
D) HI
E) HF
C) HNO3
17) Oxidation is the __________ and reduction is the __________.
A) loss of oxygen, gain of electrons
B) gain of oxygen, loss of electrons
C) loss of electrons, gain of electrons
D) gain of electrons, loss of electrons
E) gain of oxygen, loss of mass
18) What is the concentration (M) of CH3OH in a solution prepared by dissolving 11.7 g of CH3OH in
sufficient water to give 230 mL of solution?
A) 1.59 x 10-3
B) 11.9
C) 0.0841
D) 11.9 x 10-3
E) 1.59
19) What volume (L) of 0.250 M HNO3 is required to neutralize a solution prepared by dissolving 17.5 g of
NaOH in 350 mL of water?
A) 1.75
B) 50.0
C) 1.75 x 10-3
D) 0.44
E) 0.070
20) Which one of the following statements is false?
A) The actual numerical value of E can be measured.
B) ∆E = Efinal - Einitial
C) E is a state function.
D) ∆E = q + w
E) When a system undergoes a process in which it gains energy from the surroundings, the ∆E for the
process is positive.
21) Of the following, which one is a state function?
A) q
B) w
C) heat
D) H
E) none of the above
22) For a given process at constant pressure, ∆H is negative. This means that the process is _______.
A) a state function
B) endothermic
C) exothermic
D) equithermic
E) energy
23) The value of ∆Ho for the reaction below is -336 kJ. Calculate the heat (kJ) released to the surroundings
when 23.0 g of HCl is formed.
CH4 (g) + 3Cl2 (g) Æ CHCl3 (l) + 3HCl (g)
A) -2.57 x 103
B) -70.7
C) -336
D) -211
E) -177
24) The enthalpy change for the following reaction is -486.3 kJ:
2H2 (g) + O2 (g) Æ 2H2O (g)
Therefore, the enthalpy change for the reaction listed below is ________ kJ:
4H2O (g) Æ 4H2 (g) + 2O2 (g)
A) -483.6
B) 483.6
C) 967.2
D) -483.6
E) 2.34 x 105
25) A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a
__________ ∆H at constant pressure.
A) endothermic, positive
B) endothermic, negative
C) exothermic, negative
D) exothermic, positive
E) exothermic, neutral
(5 points)
At one time, a common means of forming small quantities of oxygen gas in a laboratory was to
heat KClO3:
2 KClO3(s) Æ 2 KCl(s) + 3 O2(g)
∆H = -89.4kJ
For this reaction, calculate ∆H for the formation of 3.51mol of O2
x
− 89.4kJ
=
3O 2
3.51 mol
x = 104.6kJ
= 105kJ
(10 points) Some sulfuric acid is spilled on a lab bench. It can be neutralized by sprinkling sodium bicarbonate
(NaHCO3) on it and then mopping up the resultant solution. The sodium bicarbonate reacts with
sulfuric acid as follows:
2 NaHCO3(s) + H2SO4(aq) Æ Na2SO4(aq) + 2 H2O(l) + 2 CO2(g)
Sodium bicarbonate is added until the fizzing due to the formation of CO2(g) stops. If 27mL of
6.0M H2SO4 was spilled, what is the minimum mass of NaHCO3 that must be added to the spill to
neutralize the acid?
moles H 2 SO4 = 6.0M (0.027 L _
= 0.162 mol H 2 SO4
2 NaHCO3
x
=
1H 2 SO4
0.162mol H 2 SO4
x = 0.324 mol NaHCO3
gNaHCO3 = 0.324mol (84.0 g / mol )
= 27 g
(10 points) Lithium and nitrogen react to produce lithium nitride:
6 Li(s) + N2(g) Æ 2 Li3N(s)
If 5.00g of each reactant are allowed to react, how many grams of Li3N are formed?
Moles Li =
5.0 g
6.941g / mol
= 0.720mol
5.0 g
28 g / mol
= 0.179mol
Moles N 2 =
Limiting Reagent
0.720mol
= 0.120
Li =
6
0.179mol
N2 =
= 0.179
1
Limiting Reagent is Li
2Li 3 N
x
=
6 Li
0.720mol
x = 0.240 mol Li3 N
gLi3 N = 0.240mol (34.82 g / mol )
= 8.35 g