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Unformatted text preview: Fall 2006 Exam 1H
Morlino There are 25 questions plus 2 bonus questions on this exam. Select the BEST answer to each of the
following questions. PLEASE READ THE QUESTIONS CAREFULLY! 1) The nucleus of atoms of most elements is composed of
positive protons, neutrons, and negative electrons.
7 positive protons.
neutrons and positive protons.
positive protons and negative electrons. positive protons and positive neutrons. 2) Which best describes electromagnetic radiation that has a wavelength of 0.01 nm?
visible light
iX—rays
microwaves
AM radio waves none of these 3) When light is emitted by an atom, what change has occurred Within the atom? The atom gains energy. An electron moves farther from the nucleus.
An electron moves to a higher energy level.
An electron loses energy. An electron gains energy. 4) Which of the following would have the largest heat capacity?
7 ‘100 g of water at 273K
50 g of water at 273K
50 g of water at UK
l all of these have the same heat capacity i unable to determine from information given C—1 Fall 2006 Exam Ill
Morlino 5) Calculate the wavelength in nanometers associated with an electron traveling at a speed that is 90.0% of the
speed of light. (me : 9_11 x 10—31 kg) 2.70 x 1021 nm
1.53 x 1014 nm
2.70 x 103 nm
. 2.43 x 103 nm
2.19 x 103 nm 6) How many minutes does it take for the light from the sun to reach the earth, a distance of 93 million miles? (1
km = {1.62 mile) 500 min
0.38 min
8.3 min . 93 min ) 0.14 min 7) How is the square of the wave function of an electron, Q2, related to the electron?
$2 is the uncertainty associated with the location of an. electron,
1112 is the average value of a property of the electron.
$2 is the probability of finding the electron in a particular region about the nucleus.
42 is the wavelength of the electron. 1112 represents an acceptable solution to the wave equation. 8) What is the lowest—numbered principal shell in whichf orbitals are found? C—2 Fall 2006 Exam IIl
Morlino 9) Which of the following describes a property of an electron?
principle quantum number
, angular momentum quantum number
spin quantum number
magnetic quantum number i all of these 10) A certain type of light has a wavelength of 1.2 A. Calculate the energy, in], of one photon of this radiation. (1 A
: 10—10 m) 12]
1.7,(10‘51
rzxio40j
ayxioJSJ _
17x1020} 1]) What shape are protons?
l flat discs
peanut shaped
spherical
box—like rot spherical 12) Calculate the energy change, in joules, that occurs when an electron is raised from the n = 3 to the n : 5 energy
level of a hydrogen atom. 2.18x 1018]
Z42x10‘19J
155x1049]
242]
0372] Fall 2006 Exam III
Morlino 13) What is the total number of orbitals is the principal shell n : 3?
l
4
8
9
18 14) Considering our current model of the atom, an orbital is best deﬁned as
‘a region in space in which there is a high probability of ﬁnding an electron
a circular path that an electron takes around a nucleus.
an orientation of the nucleus and electron in an atom.
a node Where the probability of finding an electron is small an energy level for eIECtrons 15) Which of the following sets is ﬂan acceptable set of quantum numbers:
n:7,ll:3,mg:+3
n:1,iZ:0,m£:0
n22,ll:l,m£:+l
n:2, ,Q:l,m£:l n=3,ﬂ=1,rnQ:—3 16) Which is I_10_t‘true for an endothermic reaction?
The enthalpy change for the reaction is positive.
The temperature of the surroundings decreases.
Heat ﬂows from the surroundings into the system»
The products have a lower enthalpy than the reactants. 1 All of the above are true. Fall 2006 Exam lll
Morlino 17) When a ball rolls down a hill which of the following increases? potential energy
kinetic energy
energy , the capacity to do work work done by the ball 18) Which statement isﬂcorrect? Heat and work are state functions.
internal energy is a state function. _
Heat is given off to the surroundings in an exothermic reaction.
Enthalpy is a state function. The enthalpy change is the heat of reaction at constant pressure. 19) Are heat and temperature the same thing?
Yes, always.
\io, never.
Yes, sometimes. .
It depends on the type of system. NOHQ Of these is correct. 20) A closed system differs from an isolated system in that
u the isolated system exchanges energy with its surroundings and the closed system does not.
the closed system exchanges energy with its surroundings and the isolated system does not.
I the closed system exchanges matter with its surroundings and the isolated system does not. I the closed system exchanges both matter and energy with its surroundings and the isolated system does
not. i the closed system exchanges neither matter nor energy with the surroundings. Fall 2006 Exam lll
Morlino 21) Given the following thermochemical equation: H2 (2;) + C12 (g) ) 2HCI (g) AH°=—184.6k1 calculate AHO for the reaction: HC1(g) —> %H2 (g) + #12 (3) +923 k]
—369.2 k; .
+3692 k1 —92‘3 k] +184.6 k] 22) The extraction of iron from iron ore may be represented by the following equation;
2 Fe203 (s) + 3 C (graphite) —> 4Fe (s) + 3 CO2 (g) Given the information below, calculate AH“ for the process per mole of FezOg. AHf Fe203 (s) = —826 k] molf1
AHf €02 (g) : 7394kjmoi~1 ~2834 k]
420 k]
+235 k]
—470 k]
+470 k] 23) If 25.0 g of water at 21°C is mixed with 45.0 g of water at 75°C, what is the final temperature of the mixture?
i 380C
56°C
63°C
48°C
, 49°C Fall 2006 Exam HI
Morlino 24) A 2.15 g sample of benzene {C6H6) is burned in a bomb calorimeter, and the temperature rises from 22.46OC to
34.34OC. Calculate the heat capacity of the bomb calorimeter. Note the following thermochemical equation: c6116 (1) + 15/2 02 (g) % 6C02 (g) + 3H20(g) AH”2—3267.5 k] 128 k] °C1
152 x 103 k] 0 C1
90.1 14°CI
35.3 k; °c1
7.58 k} °c1 25) The standard enthalpy change for the following reaction is —72.8 k]. H2 (g) + Brz (l) —i 2 HBr (g) What is the standard enthalpv of formation of hydrogen bromide?
72.8 k]
—36.4 k]
472.8 k]
—145.6 k] none of the above Bonus
26) What is the ionization energy, in J, for the loss of an electron from the lowest excited state of a hydrogen atom?
5.45 x 1049]
2.18 x 1018]
2.18 x 10—19]
2.42 x 1019] 1.56 x 10—18] Fall 2006 Exam III
Morlino 27) The heat capacity of a bomb calorimeter is found to be 5.68 k] DC'I. When a 1.652 g sample of glucose, C51112
06, is burned in the calorimeter, the temperature of the calorimeter increases from 24.560C to 29,100C. Calculate
g the AH for the following reaction: \9
as)“; C6H1206 (s) + 602 (g) —> 6 (:02 (g) + 6H‘20(g) A Main?
9 3?};
A) —25.8 k _
\:\\"@ B)156k]] ATICZQ.10—24.5£p)°c;—4.€4°C2
C) 25.8 k} R Jr
D) 42.6 k] 0:220le : 5, [05’ kA/ac
@—2.81 x 103 k]
Bswmpie : _Z tale :4 mc‘lcn gamma,” :@$$5H AT
Zmlorimete}: (5'58 K‘X/ocylléﬁ’?)
Zmbflmeieo: 2 5. 7 ‘i K3
ZsmPle : "‘ (25.70: m) M._ ‘257‘1‘15 : AH: alselkyca césmple # 1.5523 C8 ...
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 Fall '07
 MORLINO
 Chemistry

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