Review Sheet #1 Atomic Structure
Name_______________________ Per.
1. The following scientists and the research that they carried out was pivotal in creating the Nuclear Model
(Theory) of the atom. Please match the experiment and finding on the left with scientist on the right :
______ a) Oil Drop Experiment; Using charge/mass ratio from cathode
ray studies the mass and charge of an electron was determined
______ b) Gold Foil Experiment; Alpha particles directed at a piece of gold
foil were deflected supporting the existence of a dense positively
charged nucleus.
______ c) Canal Ray Experiment; Bema of proton rays (canal rays) were passed
through an electric field and were deflected away from the positive
plate supporting the existence of protons
______ d) Cathode Ray Experiment; A beam of electrons were passed
through an electric field and were deflected away from the negative
plate supporting the existence of electrons
a) Eugene Goldstein
b) Robert Millikan
c) JJ Thompson
d) Ernest Rutherford
2.
Symbol
2+
58
28
33
Ni
16
2-
S
________________ _______________
Number of Protons
________________ _______________
10
26
Number of Neutrons
________________ _______________
10
30
Number of Electrons
________________ _______________ _______________
Hyphen Notation
Name of Species
(Atom or Ion)
________________ _______________ _______________ ________________
23
________________ _______________ _______________ ________________
b. How are ethanol and dimethyl ether related?
3.
Naphthalene
Acetic Acid
Empirical Formula
__________
CH2O
Empirical Mass
___________
____________
Molecular Mass
____________
60.05 g/mol
Molecular Formula
C10H8
_______________
4. A compound contains 1.10 mol of K, 0.55 mol of Te, and 1.65 mol of O. What is the empirical formula of this
compound?
5. A hydrocarbon CxHyOz (MM = 328.4 g/mol) is 73.14% C and 7.37% H; the remainder is oxygen. What are the
compounds empirical and molecular formulas?
1
Review Sheet #1 Atomic Structure (Contd.)
6. Tin metal (Sn) and purple iodine (I2) combine to form orange, solid tin iodide with an unknown formula. All of the
iodine reacts.
Sn (s) + I2 (s)  SnxIy
Mass of Tin (Sn) in original sample:
1.056 g
Mass of Iodine (I2) in original Sample:
1.947 g
Mass of Unreacted tin (Sn) recovered after the reaction:
0.601 g
Mass of Sn in Compound:
_________g
Mass of Iodine in Compound: _________g
Empirical Formula
___________
Name of Compound
________________________
7. Hydrated Nickel (II) chloride is heated strongly and dehydrated. If 0.235 g of NiCl 2 . x H2O gives 0.128 g of
anhydrous NiCl2 what is the name formula and molar mass of the hydrate?
NiCl2 . x H2O + Heat  NiCl2 (s) + x H2O
8. a) Name and determine the molar mass of the compound with the formula K 2S
_______________________
b) What is the mass ratio of K to S (K:S)
________________________
c) How many grams of S are in 5.0 g of the compound, K 2S?
________________________
d) If you wanted 10.0 g of K, how many grams of the compound, K 2S would you
need?
________________________
2
Review Sheet #2 Quantum Chem./Periodic Table
Name__________________________
Per. #______
1. An electron in a hydrogen atom changes from orbital n = 2 to orbital n = 5
a) For this transition to occur, will the electron need to absorb or release energy in the form of a photon of light?
Explain
b) Using the Bohr Equation, what will be the energy of the photon?
_______________J
c) What will be the frequency of the photon light?
______________Hz
d) What will be the wavelength of the photon of light?
_____________m
e) Would this photon of light be in the visible region. If yes what color?
V
I
B
Y
O
R
400 nm
700 nm
_______________
2. Atomic properties and periodic trends
Circle the appropriate term to complete the diagram below:
As you move from left to right across the periodic table the z-effective acting on electrons ___________
because of an increase in ___________ with no change in ____________________. As you move top to
bottom down the periodic table the z-effective acting on electrons ___________ because of an increase in
___________ .
3. Place the following elements in the orders indicated below: F, Al, Ca, N, C, Cs
Smallest to largest Atomic radius:
___________________________________________
Smallest to largest Ionization Energy: ___________________________________________
Largest to Smallest Electronegativity: ___________________________________________
Which species has the most negative Electron Affinity?
______________
Which species is has the most metallic character?
______________
Which species has the least metallic character?
______________
4. An element found in period three has the following ionization energies:
IE1
IE2
320 kJ
680 kJ
IE3
16000kJ
IE4
48000 kJ
a) What Ion would most likely be formed by an atom of this element? __________
b)What is the elements identity?
__________
3
Review Sheet #3 Solids
Name__________________________ Per. #______
1. Match the solid at the left with the type of solid at the right.
____ SiO (s)
a) Ionic Solid (Lattice of positive and negative ions held together by electrostatic forces)
____ MgO (s)
b) Covalent Solid (London IM Forces)
____ CO2 (s)
c) Covalent Solid (London and Dipole-Dipole IM Forces)
____ Cr (s)
d) Covalent Solid (London, Dipole-Dipole, H-Bonding IM Forces)
____ NH3 (s)
e) Metalic Solid (Closely packed lattice of cations with delocalized electrons throughout)
____ PH3 (s)
f) Giant Molecule (Network Solid)
2. a) True or False. If the statement is false change the statement to make it true.
______ Coulomb’s Law ( Ionic Bond Energy = k q1 q2 ) is used determine ionic bond strength.
r2
______ The larger the product of the charge on the cation (q1) and charge on anion (q2) the greater the ionic
bond strength.
______ The larger the radius of the ions involved in an ionic compound the weaker the ionic bond strength.
b) In each of the following pairs, circle the formula of the ionic solid that has the highest melting point then
explain why it has the higher melting point using Coulomb’s Law
i)
NaCl
ii) Li2O
or
CaO
or Na2O
IBE = k q1 q2
r2
IBE = k q1 q2
r2
3. Match the property below with the compound
____ Lustrous
____ Solid is malleable and ductile
____ Can conduct heat and electricity when in solid form
____ Very brittle solid, held together by ionic bonds
____ Occurs between atoms (a) metal(s) and non-metal element(s)
____ Occurs between atoms of two or more non-metal elements
____ Very brittle solid, held together by IM Forces
____ Can conduct electricity ONLY when dissolved or melted
a) Ammonia (NH3)
b) Iron (Fe)
c) Potassium Iodide (KI)
5. These questions refer to carbongraphite and carbondiamond:
a. These two forms are examples of ________________ of
carbon.
b. What is the hybridization of each carbon in
Diamond
Graphite
Diamond: ________
Graphite: ________
c. Referring to bonding of the two species in your answer why is
diamond an extremely hard abrasive but graphite is a great
lubricant?
d. Referring to bonding of the two species in your answer why can solid graphite conduct electricity but solid
diamond can’t?
4
Review Sheet #4 Molecular Structure
Name____________________ Per. #______
1. Draw Lewis structures for CH4 , PH3, H2O. According to VSEPR the bond angles in these molecules get
progressively smaller. Why? Include Lewis structures for each in your answer.
2. The normal boiling point of CCl4 (350K) is greater than the boiling point of CF4 (145 K)?
a) Identify the intermolecular forces in each substance? CCl4: __________________CF4_________________
b) Account for the difference in boiling points?
3. a) Place the species in each group from least to most polar bond:
i.
H-F, F-F , C-H
____________________________________________________________
ii. F-Cl, O-Cl , N-Cl
____________________________________________________________
iii. S-Cl, Cl-Cl, P-Cl
____________________________________________________________
b) Draw the Lewis structure for PF5 and give its shape, bond angles, and hybridization.
c) Why can PF5 exist but NF5 cannot? Explain clearly
d) Both BF3 and NF3 have polar bonds but only NF3 has molecular dipoles (dipole moment; δ+ & δ - end).
Explain
4.
H
H -C-H
H
The bonds in CH4 are identical because of ( resonance OR hybridization).
O=S-O
O
The bonds in SO3 are identical because of ( resonance OR hybridization).
5
Review Sheet #4 Molecular Structure (Contd.)
5. a) i. Draw the Lewis structure for SO3 and SO2 all resonance structures, if they apply.
ii. What is the S…O bond order in SO3: __________
SO2:____________
iii. Which S...O bond will be shorter, the one in ( SO3
or
SO2 )
iii. Which S...O bond will be stronger, the one in ( SO3
or
SO2 )
6. Two Lewis structures can be drawn for the OPF3, as shown below:
a) Assign formal charges to each atom in each structure above. Which, of the two, best represents a molecule
of OPF3. Justify your choice in terms of formal charge.
b) How many sigma (σ )bonds are in…
How many pi (π) bonds are in…
Structure 1: _________
Structure 1: _________
Structure 2:__________
Structure 2:__________
7. Given the structural formula for propyne below,
1
2
a) Indicate the hybridization of C1: ____________ and C2:_____________
b) How many sigma (σ ) and pi (π) bonds are in a molecule of propyne:
sigma (σ ):_______________ pi (π) bonds:___________
6
Review Sheet #5 IM Forces and Phases
Name____________________ Per. #______
1. a) Draw Lewis structures for the following species and Identify the IM forces that hold the following liquids together:
A. Carbon Disulfide (CS2)
B. Phosphine (PH3)
C. Water (H2O)
IM Forces:______________
IM Forces:______________
IM Forces:______________
b) i) What is the vapor pressure of phosphine at 50oC? _________mmHg
Carbon Disulfide
Phosphine
ii) What is the normal boiling point of phosphine? ____________0C
Water
iii) At what temperature does carbon disulfide have a pressure of
450 mmHg?
____________OC
iv) At what temperature does water boil on top of Mount Everest
(Patm = 225 mmHg
_____________OC
v) Why does phosphine have a lower vapor pressure than carbon
disulfide at any temperature?
c) If the intermolecular forces in a liquid increase…
i.
the normal boiling point of a liquid
___________________________
ii.
the vapor pressure of a liquid at a given temperature
___________________________
iii.
the viscosity of the liquid
___________________________
iv.
the enthalpy of vaporization (ΔH
o
vap
)
___________________________
d) Phase Diagrams
i. Use the following information to sketch the phase diagram for Phosphine, PH3:
Normal Boiling Point: 80oC
Normal Freezing Point: 30oC
Triple Point:
300 mmHg and 15oC
mmHg
1000
800
760 mmHg
600
400
200
10
20
30
40
50
60
70
80
90
100 0C
7
Review Sheet #5 IM Forces and Phases (Contd.)
ii. Please label the Solid, Liquid, Gas region, MP/FP Line, BP/CP Line, and sublimation line.
iii. What change(s) occur as you move from 15oC at 500 mmHg to 100oC
iv. What change(s) occur as you move from 200 mmHg 20oC at to 800 mmHg
v. List the states of matter in order from least to most dense.
_________________________________________
Least

Most
vi. Will solid phosphine sink or float in liquid phosphine? Justify your answer.
2.
ix.
vi vii viii
Species A
________
________
Species B
________
________
b. For Species B, which is larger ΔHoFusion or
ΔHoVaporization Fusion ? Justify your answer
v
ii
a. Melting Point
Boiling Point
iii iv
i
Heat Added (J)
Species A
Species B
3. a. Gases behave ideally at…
i. ( high or low ) temperatures. Why?
ii. ( high
b.
or low ) pressures. Why?
Ideal gasses have ( weak or strong ) intermolecular (IM) forces.
_____c. O2 will behave most ideally at what two conditions a) 298 K and 1.5 atm b) 273 K and 1.5 atm b) 273 K and 0.50atm
_____d. Which gas will behave most ideally at 300 K? a) CH4
b) CCl4
c) NH3
d. H2S
8
Review Sheet #6 Gases I
Name__________________________ Per. #______
1. Given each situation below identify the pressure of the gas sample Patmospere = 760 mmHg;
(i)
_________________mmHg
(ii)
_________________mmHg
(iii)
_________________mmHg
2.
2NO (g) + O2 (g)  2 NO2 (g)
A mixture of 4.0 L of NO at 25oC and 2.0 atm is mixed with 2.0 L of O2 at 25oC and 4.0 atm.
a) Identify the moles of each reactant?
nNO =
nO2 =
b)
Identify the limiting reactant.
c)
How many moles of the excess reactant remain?
d)
e)
How many moles of NO2 are produced?
i. If the gases present after the reaction is complete (answers to c and d) are held at 25oC in a 5.0 L container, what will be
the pressure of all the gases?
ii. What would be the new pressure if the gases from part d were moved to a 8.0 L container at 50oC?
P1V1 = P2V2
T1
T2
3. 2.0 mol of Ne is mixed with 5 mol of CH4 and 3 mol of PCl5. The total pressure of the gases is 100 atm.
a)
What is the pressure of each gas?
b) Which gas behaves least ideally. Explain
9
Review Sheet #7 Gases II
Name__________________________ Per. #______
1. The oxygen produced in this experiment was collected
by displacement of water at 25oC at a total atmospheric
pressure of 740 torr. The volume of the gas collected
was 0.6325 L, and the vapor pressure of water at 25oC is
21 torr (get this from a table of Water Vapor Pressures).
a) Calculate the pressure of “Dry” O2 collected over water
b) Calculate the moles of O2 produced during the reaction (assume 100% yield)?
c) Calculate the volume of gas if it was corrected to STP conitions?
P1V1 = P2V2
T1
T2
d) What was the experimental molar volume of the gas at STP (L O2/mole O2) ?
_______L
= _________L/mol
mol
2. Consider the three flasks below. Assume the connecting tubes have negligible volume
What is the partial pressure of each gas when the stopcocks are
opened?
1.00 L
100 mmHg
1.00 L
300 mmHg
2.00 L
200 mmHg
What is the total pressure in the system?
10
Review Sheet #8 Formulas - Energy
Name______________________ Per. #______
1. Three volatile compounds X, Y, and Z each contain element Q. The percent by weight of element Q in each compound was
determined. Some of the data obtained are given below.
Percent by weight
Molecular
Compound
of Element Q
Weight
X
64.8%
?
Y
73.0%
104.
Z
59.3%
64.0
(a)
The vapor density of compound X at 27C and 750. mm Hg was determined to be 3.53 grams per liter. Calculate the
molecular weight of compound X.
(b)
Determine the mass of element Q contained in 1.00 mole of each of the three compounds.
X : ____________
Y:____________
Z:____________
(c)
Calculate the most probable value of the atomic weight of element Q.
(d)
Compound Z contains carbon, hydrogen, and element Q. When 1.00 gram of compound Z is oxidized and all of the carbon
and hydrogen are converted to oxides, 1.37 grams of CO 2 and 0.281 gram of water are produced. Determine the most
probable molecular formula of compound Z.
2. List three ways of separating homogeneous mixtures into pure species (elements or compounds)
________________________
_________________________
_________________________
3. List three ways that you can maximize the rate at which a solid dissolves:
________________________
_________________________
_________________________
4. If you add a non-volatile solute to a solvent, relative to pure solvent, the solution’s ….
i.
normal boiling point
( increases or
decreases )
ii.
normal freezing point
( increases or
decreases )
iii.
vapor pressure
( increases or
decreases )
iv.
osmotic pressure
( increases or
decreases )
11
Review Sheet #8 Formulas - Energy (Contd.)
3. 1.0 m C6H12O6; 1.0 m NaCl; 1.0 m Mg(NO3)2; 1.0 mFeCl3; pure water
(ΔTf = kf m i
and
ΔTb = kb m i )
i. Place the above in order from lowest to highest freezing point: __________________________________________
ii. Place the above in order from lowest to highest boiling point: __________________________________________
ii. Place the above in order from lowest to highest vapor pressure: __________________________________________
12
Review Sheet #9 Solutions I Name__________________________ Per. #______
Unsaturated,
Dilute or
Saturated,
Concentrated
Supersaturated
1a. Complete the table below:
Qsp
<, =, >
Ksp
1.0 g KClO3/100g @ 5oC ______________ ____________
_____ __
130 g KI/100g @ 5oC
______________ ____________
_______
o
______________ ____________
_______
5.0 g SO2/100g @ 70 C
b. Identify the following as strong, weak, or non-electrolytes and species.
Strong, Weak, Non-electrolyte
Species formed in Solution
HNO3 (aq)
_________________________
_____________________
C6H12O6 (aq)
_________________________
_____________________
NaF (aq)
_________________________
_____________________
NH4Cl (aq)
_________________________
_____________________
NaOH (aq)
_________________________
_____________________
NH3 (aq)
_________________________
_____________________
HF (aq)
_________________________
_____________________
AgNO3 (aq)
_________________________
_____________________
FeCl3 (aq)
_________________________
_____________________
c. What aqueous solution(s) in part b…
i.
Could you mix to form a precipitate:
__________________________________________
ii.
Could you mix to form a buffer with a basic pH:
__________________________________________
iii.
Could you mix to form a buffer with a acidic pH:
__________________________________________
iv.
Is/Are weak acid(s)
__________________________________________
v.
Is/Are weak base(s)
__________________________________________
vi.
Is/Are basic salt(s)
__________________________________________
vii. Is/Are acidic salt(s)
__________________________________________
viii. Is/Are neutral salt(s)
__________________________________________
vii. Is/Are colored solution(s)? What color?
__________________________________________
viii. Would have the greatest change in colligative properties?
__________________________________________
d. What three factors affect the amount of solute than can dissolve in a solvent?
i. _____________________
ii._____________________
iii. ____________________
e. The partial pressure of CO2 gas above a sealed cold soda at 15oC is 3.0 atm. If the temperature of the soda was
increased to 30o the solubility of CO2 in solution would (increase or decrease), the vapor pressure of water would
(increase or decrease), the pressure of CO2 gas above the solution would (increase or decrease).
13
Review Sheet #9 Solutions I (Contd.)
2. Vapor Pressure of a solution: (Raoult’s Law:
Psolution = Posolvent Χsolvent
a. The vapor pressure an aqueous solution of urea, CH4N2O, is 290 mmHg. The vapor pressure of pure water at this
temperature is 355 mmHg. Calculate Xsolvent and Xsolute
b. Water has a vapor pressure of 300. mmHg at a given temp. The mole fraction of a non-volatile solute is 0.15 What is
the mole
fraction of solvent? What is the Psolution?
3. (Raoult’s Law:
Psolution = (Posolvent Χsolvent) + (Posolvent Χsolvent)
A solution is prepared by mixing 5.80 g of acetone (C3H6O); MM=58) and 29.8 g of chloroform (HCCl3; MM=119). The
vapor pressures of pure acetone and pure chloroform at 35oC are 300 and 400 torr, respectively.
a) Calculate the moles of acetone and chloroform. The species present in the greatest molar amount is the solvent.
b) Calculate the mole fraction of each species; Χacetone and Χchloroform.
c) Calculate the vapor pressure of the solution.
d) When measured, the vapor pressure of the solution was actually 360 torr. Was the solution an ideal solution (or a
positive or negative deviation from Raoult’s Law)? Explain
14
Review Sheet #10 Solutions II
Name__________________________ Per.______
1. Phenanthrene, C14H10 (MM = 178 g/mol), is an aromatic hydrocarbon. If you dissolve some phenathrene in 50.0 g of
benzene, C6H6 (MM = 78 g/mol), the boiling point of the solution is 80.51 oC. (The normal boiling point of benzene is
80.10oC and the kBP of benzene is 2.53oC/m; dsolution = 0.79 g/mL)
a) What is the molality of the solution?
b) How many moles of phenathrene were added to make the solution? What was the mass of phenathrene?
c) What is the mass percent of the solution? molality of the solution? molarity of solution?
Mass
Solute (phenanthrene) ________g
Moles
________moles
Solvent (benzene)
________g
________moles
Solution
________g
________moles
Volume of
________L
Solution
2. A 10.7 m solution of NaOH has a density of 1.33 g/mL at 20oC. Calculate the mole fraction of NaOH, weight
percentage of NaOH, and molarity of the solution.
Solute (NaOH)
Mass
________g
Moles
________moles
Solvent (H2O)
________g
________moles
Solution
________g
________moles
Volume of
________L
Solution
15
Review Sheet #10 Solutions II (Contd.)
16
Review Sheet #11 Solutions III
Name______________________ Per.______
1. Solutes with similar forces holding them together tend to dissolve in each other (polar solute-polar solvent OR nonpolar solute in
non-polar solvent).
Solute
Forces holding solute together
Most Soluble In…
C4H10 Water
Ideal Solution (Y/N)
Predicted ΔHsolution (+/-)
NaCl (s)
_______________________
______ _______
________________
___________________
CH3OH (l)
_______________________
______ _______
________________
___________________
C6H6 (l)
_______________________
______ _______
________________
___________________
______ _______
________________
___________________
_________
2. Using the difference in the size of hydrophobic and hydrophilic regions of each species below, describe why Vitamin C
is soluble in water but Vitamin E is not. (Do not say “Like Dissolves Like!”)
3. Why does soap dissolve polar and non-polar solutes?
Soap Molecule
4. The formula and the molecular weight of an unknown hydrocarbon compound are to be determined by elemental
analysis and the freezing-point depression method.
(a) A solution is prepared by dissolving 2.53 grams of p-dichlorobenzene (molecular weight 147.0) in 25.86 grams of
naphthalene (molecular weight 128.2).
i. Calculate the molality of the p-dichlorobenzene solution.
ii. Calculate the mole fraction of p-dichlorobenzene?
(b) The vapor pressure of pure p-dichlorobenzene at 35oC is 150. millimeters of Hg. Calculate the vapor pressure of
p-dichlorobenzene over the solution described above at 35oC.
17
Review Sheet #11 Solutions III (Contd.)
(c) The freezing point of pure naphthalene is determined to be 80.2oC. The solution prepared in (a) is found
to have an initial freezing point of 75.7oC. Calculate the molal freezing-point depression constant of
naphthalene.
Freezing Point Curve
80.2 C
Pure naphthalene
75.7oC
P-dichlorobenzene Solution
(e) A solution of 2.42 grams of the unknown hydrocarbon dissolved in 26.7 grams of naphthalene is found
to freeze initially at 76.2oC.
i)
Calculate the apparent molality of the unknown hydrocarbon solution on the basis of the
freezing-point depression experiment above?
ii)
What is the molar mass of the hydrocarbon?
5. i. To convert molarity of a solution to - molality, mole fraction, or % by mass you need to know its
_____________
iii.
___.
Which unit of concentration is changed by a change in temperature?
_______________________________
6. a. Concentrated aqueous ammonia is 14.8 M and a density of 0.90 g/mL at 20 oC. Calculate its mole fraction
of NH3,
weight percentage of NH3, and molality of the solution.
Solute (NH3)
Mass
________g
Moles
________moles
Solvent (H2O)
________g
________moles
Solution
________g
________moles
Volume of
________L
Solution
18
Review Sheet #12 Kinetics I
Name__________________________ Per.______
2 HI  H2 + I2
1. Use the graph and either tangents or secants to
answer the following problems.
What is the instantaneous rate of the disappearance
of HI at 100 s?
_____________ M/s
What is the average rate of the disappearance of HI
between 0.0 s and 400 s?
_____________M/s
What is the initial rate of the disappearance HI?
_____________M/s
19
Review Sheet #12 Kinetics I (Contd.)
2. Please indicate which type of reaction (0-order, 1-order, or 2-order) each of the following statements refers to.
_____ t1/2 = 1/k [reactant]i
_____ The half-life DOES NOT depends on the initial concentration of reactant.
_____ The slope of 1 / [reactant] vs time is linear.
_____ 1/[R]
_____ [R]
_____ The decay of radioactive isotopes.
_____ The slope of [reactant] vs time is linear.
_____ The slope of ln [reactant] vs time is linear.
t
t
_____ t1/2 = 0.693/k
_____ t1/2 = [reactant]i / 2 k
_____ln[R]
_____ [reactant]f = k t + [reactant]i
_____ 1/[reactant]f = k t + 1/[reactant]i
_____ 1n[reactant]f = k t +ln [reactant]i
20
Review Sheet #13 Kinetics II
Name__________________________ Per.______
1. For the following reaction, answer the questions that follow:
NO2 (g) + CO (g)  NO (g) + CO2 (g)
Rate = k [NO2]2
a) Given each scenario below, identify how the rate will be affected and whether k or [NO] is affected.
Effect, if any, on reaction rate
Effect on k
Effect on [NO]
i. [NO2] is doubled
_______________________
_________
___________
ii. [CO] is doubled
_______________________
_________
___________
iii. catalyst is added
_______________________
_________
___________
iv. Temperature is
Doubled
________________________
_________
____________
v. PNO2 is increased
_______________________
_________
___________
vi. [NO2] is halved
_______________________
_________
___________
b) What is the order with respect to [NO2]:____ [CO]:____ Overall Order: ____ Units of k: ____________
c) Which graph of data would be linear when plotted:
[NO2] vs t
ln [NO2] vs t
1/[NO2] vs t
Rate = k [NO2]2
d)
i. Using the Boltzmann Distribution, energy diagram, and Rate Law above, describe and show why adding a
catalyst increases the reaction rate: NO2 (g) + CO (g)  NO (g) + CO2 (g)
ii. Is the reaction endothermic or exothermic?
iii. Does the addition of a catalyst affect ΔHoreaction? ____________
________________
Eaf? ___________
Ear? ___________
iv. On the energy diagram, draw what the addition of a catalyst would do to the diagram if you have not already
done so.
21
Review Sheet #13 Kinetics II (Contd.)
2 NO(g) +2 H2(g)  N2(g) + 2 H2O(g)
2. Experiments were conducted to study the rate of the reaction represented by the equation above. Initial
concentrations and rates of reaction are given in the table below.
Initial Concentration
Initial Rate of Formation of N2
(mol/L)
Experiment
[NO]
[H2]
(mol/L.min)
1
0.0060
0.0010
1.8 x 10-4
2
0.0060
0.0020
3.6 x 10-4
3
0.0010
0.0060
0.30 x 10-4
4
0.0020
0.0060
1.2 x 10-4
5
0.0030
0.0050
?
6
?
0.0300
0.06
(a)(i) Determine the order for each of the reactants, NO and H2, from the data given and show your reasoning.
(ii) Write the overall rate law for the reaction.
(iii) What is the overall Order of the reaction? ______________
(b) Calculate the value of the rate constant, k, for the reaction. Include units.
(c) For experiment 1, calculate the concentration of NO remaining when exactly one-half of the original amount of
H2 had been consumed.
(d) Solve for missing rate in Experiment 5.
(e) Solve for the missing concentration of [NO] in Experiment 5
22
Review Sheet #13 Kinetics II (Contd.)
(f) For Experiment 2, determine the rate of initial disappearance of NO
(g) The following sequence of elementary steps is a proposed mechanism for the reaction.
I.
II.
III.
NO + NO  N2O2 (fast)
N2O2 + H2  H2O + N2O (slow)
N2O + H2  N2 + H2O (fast)
(i) Based on the data presented, which of the above is the rate-determining step? ___________
(ii) identify any intermediates in the mechanism __________________
(iii) Show that the mechanism is valid?
( Yes or No ) Does the sum of the sequence of reactions give the balanced overall reaction
( Yes or No ) Does the rate law for the rate determining step (slow step) agree with the observed
Experimental Rate Law -see (aii)
(h) The diagram below at right shows the energy pathway for the reaction 2 NO(g) +2 H2(g)  N2(g) + 2 H2O(g) .
Clearly label the following directly on the diagram.
(i) The activation energy (Ea) for the forward reaction
(ii) The enthalpy change (ΔH) for the reaction:
(iii) Sketch what adding a catalyst would do to the diagram.
(iv) Is the reaction exothermic or endothermic: ____________
23
Review Sheet #14 Chem Equilibrium I
Name_______________________ Per.______
1. The reaction for the formation of nitrosyl chloride:
2 NO (g) + Cl2 (g)  2NOCl (g)
The reaction above was studied at 25oC. The pressures at equilibrium were found to be:
PNOCl = 1.2 atm PNO = 0.05 atm PCl2 = 0.30 atm
a) Write-out the Kp expression and calculate the value of Kp for this reaction at 25oC.
b) Calculate the value of Kc for this reaction at 25oC
24
Review Sheet #14 Chem Equilibrium I (Contd.)
c) What is the numerical value of KP for the following reaction:
2NOCl (g) 2 NO (g) + Cl2 (g)
KP: ________________
4 NO (g) + 2Cl2 (g)  4NOCl (g)
KP: ________________
2. Equilibrium constants for reactions that combine two or more other reactions. Determine overall reaction and
value of KC and identify if the overall reaction is reactant or product favored
a) Rxn 1:
3/2 O2

O3 (g)
K1= 2.5 x 10-29
Rxn 2:
2 NO (g) + O2 (g)

2 NO2 (g)
K2= 2.25 x 1012
Desired:
NO (g) + O3 (g)

NO2 (g) + O2 (g)
b) When carbon dioxide dissolves in water it produces carbonic acid, H 2CO3
Rxn 1:
H2CO3(aq) + H2O (l) 
HCO31- (aq) + H3O1+(aq)
1Rxn 2:
HCO3 (g) + H2O (l) 
CO32- (aq) + H3O1+
Desired:
_________________  ____________________
c) Determine K net for the following reaction @ 298
Rxn 1:
H2SO3 (aq)

Rxn 2:
HSO31- (aq)

2+
2Rxn 3:
Ca (aq) + SO3 (aq)

Desired:
H2SO3 (aq) + Ca2+ (aq) 
Knew:________________
(aq) which ionizes in two steps.
Ka1= 4.2 x 10-7 @ 25oC
Ka2= 2.25 x 1012 @ 25oC
Knew:_____________ @ 25oC
K
H1+ (aq) + HSO31- (aq)
H1+ (aq) + SO32- (aq)
CaSO3 (s)
CaSO3 (s) + 2 H1+ (aq)
Ka1= 1.0 x 10-2 @ 298 K
K2= 6.0 x 10-8 @ 298 K
Ksp= 5.0 x 10-5 @ 298 K
Knew:________ @ 298 K
25
Review Sheet #15 Chem Equilibrium II
Name_______________________ Per.______
1. Characterize each of the following reactions as product- or reactant-favored
i.
ii.
H2O (l)
CO (g)

+
Cl2 (g)

H2 (g) + ½ O2 (g)
COCl2 (g)
KP = 9.0 x 10-41
Kp = 6.6 x 10
11
_____________
_____________
2. A mixture of CO and Cl2 g is placed in a reaction flask. Initially [CO] = 0.0102 mol/L and [Cl2] = 0.00609 mol/L
CO (g) + Cl2 (g)  COCl2 (g)
I
C
E
When the reaction has come to equilibrium at 600 K, [Cl2] = 0.003045 mol/L.
a) Calculate the [CO] and [COCl2] at equilibrium?
b) Calculate K
3. Ammonium hydrogen sulfide is a crystalline solid that decomposes as follows:
NH4HS(s)  NH3(g) + H2S(g)
I
C
E
10.00 g of solid NH4HS (s) is placed in a 5.0 L evacuated vessel at 25ºC (298 K). After equilibrium is attained,
The total pressure inside the vessel is found to be 0.659 atmosphere. Some solid NH4HS remains in the vessel
at equilibrium.
a) For this decomposition, write the expression
for KP and calculate its numerical value at 25ºC.
c) What mass of NH4HS (s) remains?
b) How many moles of NH3 is present in the container?
Molecules of NH3?
e) If a leak developed which gas would effuse faster?
How many times faster?
f) What would adding more NH4HS (s) do to the value of Kp
26
Review Sheet #16 Chem. Equilibrium III Name_______________________ Per.______
C(s) + H2O(g)  CO(g) + H2(g)
ΔH = +131kJ
1. A rigid container holds a mixture of graphite pellets (C(s)), H2O(g), CO(g), and H2(g) at equilibrium. State
whether the number of moles of CO(g) in the container will increase, decrease, or remain the same after each of
the following disturbances is applied to the original mixture and what will happen to the value of K eq (increase,
decrease, or remain the same) . For each case, assume that all other variables remain constant except for the given
disturbance. Explain each answer with a short statement.
(a)
Additional H2(g) is added to the equilibrium mixture at constant volume.
(b)
The temperature of the equilibrium mixture is increased at constant volume.
(c)
The volume of the container is decreased at constant temperature.
(d)
The graphite pellets are pulverized.
2. Suppose you place 0.086 mol of Br 2 in 2.00 L flask and heat it to a high temperature, at which the halogen
dissociates into atoms.
a) If at this temperature the Br2 is 20% dissociated, at 25oC calculate K.
Br2 (g)  2 Br (g)
I
C
E
a) At 50oC Br2 is 35% dissociated. Is this reaction endothermic or exothermic? Justify your answer.
3. The equilibrium reaction between aqueous iron (III) ion, Fe3+ and aqueous thiocyanic acid, HSCN is an equilibrium reaction
(see above). The product of the reaction is the aqueous complex thiocyanatoiron (III) ion, FeSCN 2+ and aqueous hydrogen ion.
The concentration of the thiocyanatoiron (III) ion, FeSCN2+ can be determined using spectroscopy because is wine-red
colored. A set of known concentrations of the thiocyanatoiron (III) ion, FeSCN2+ ions of different molarities were prepared
and their absorbances were measured.
a. At what wavelength was absorbance measured?
__________________
b. The absorbances of solutions of 0.02, 0.04, 0.06, 0.08,
0.10M. The data was plotted to the right:
27
Review Sheet #16 Chem. Equilibrium III (Contd.)
Fe3+ (aq) +
M
HSCN (aq)  
FeSCN2+ (aq) +
H1+ (aq)
0.500 M
0.000 M
5.000 M
I
0.100
C
________M
_________M
_________M
5.000 M
E
________M
_________M
________M
5.000 M
From ABS & Standard Curve
c. For an experiment, the initial amounts of reactants are given above. After equilibrium is reached by the
mixture the absorbance was measured at 445 nm and found to be 0.50. Using the spectrophotometry standard
curve for FeSCN2+ (aq), determine the equilibrium concentration of FeSCN2+ (aq). Then complete the ICE
diagram above.
______________M FeSCN2+(aq)
d) Write-out the equation for Kc and determine its value.
e) What is the molar absorptivity constant (Є) for FeSCN2+ (aq) (Path length = 1.0 cm)?
A= ЄlC
28
Review Sheet #17: General Acids/Bases
Name_______________________ Per.______
1. Match the definition with the term that best correlates to it. No definition will be
used more than once.
_____1. Triprotic acid
A) A Bronsted-Lowry acid
_____2. Conjugate acid
B) A Bronsted-Lowry base
_____3. Conjugate base
C) Description of a substance that can act both as an acid and a base
_____4. Conjugate acid-base pair
D) Acid that contains three ionizable hydrogens
_____5. Lewis acid
E) Acid that contains two ionizable hydrogens
_____6. Hydrogen-ion acceptor
F) Acid that contains one ionizable hydrogen
_____7. Hydrogen-ion donor
G) Particle that remains when an acid has donated a hydrogen ion
_____8. Diprotic acid
H) An electron-pair acceptor
_____9. Lewis base
H) An electron-pair acceptor
_____10. Monoprotic acid
I) An electron-pair donor
_____11. Amphoteric
J) Particle formed when a base gains a hydrogen ion
K) Two substances that are related by the loss or gain of a single
hydrogen ion
2. For the list that follows, indicate the species that is amphoteric (A), a Bronsted-Lowry Base (BLB), or is a Bronsted-Lowry Acid
(BLA)
_________ NH41+
________ HSO21_________ SO32HC2H3O2(aq) + CN–(aq)  HCN(aq) + C2H3O2–(aq)
3. The reaction represented above has an equilibrium constant equal to Ka = 3.7 x 104
Is the reaction product or reactant favored? ___________________________________________________
Identify the following acids in the reaction: Acid:______________
Conjugate Acid:______________
Identify the two bases in the reaction:
Base:______________
Conjugate Base:______________
Identify the strongest acid:
______________________________
Identify the strongest base:
______________________________
4. Complete the reactions below. Write-out the net ionic equation for each.
+ H2O (l)
 ____________________________________________
Na2O (s) + H2O (l)
 ____________________________________________
SO2 (g)
5. Write-out the reaction that HClO4 undergoes in water and calculate the concentration of HClO4 solution that has a pH
of 3.85?
______ M
HClO4 (g)
+
H2O (l)
 __________________________
pH = 3.85
29
Review Sheet #17: General Acids/Bases (Contd.)
6. You have a 1 x 10-2 molar solution of HCN. (For HCN, Ka = 4.0 Χ10–10.)
a) What is the Lewis Structure for HCN?
b) Write-out the Ka expression
Number of Sigma Bonds(σ):
Pi Bonds (π):
__________
__________
c) Complete the ICE diagram for the ionization of
1.0 X 10-2 M HCN and calculate its pH?
____________________ ___________________
I
C
E
d) What is the percent ionization of HCN?
30
Review Sheet #18 Acids
Name__
_____________________ Per.______
WEAK ACID
1. The acid ionization constant, Ka, for propanoic acid, C2H5COOH, is 1.3 x 10-7
i) Write out the ionization of propanoic acid in water and ICE diagram for a 0.20 M solution of this acid
__________________________________ __________________________________
I
C
E
iii) Write out the Ka expression:
Ka = _______________
iii) What is the percent ionization of the propanoic acid molecules?
iv) Complete the table for this solution
pH:_______
POH________
[H3O1+]: ___________ [OH1-]:_____________
v) You add .020 moles of NaOH to 200 mL of the original acid what is the pH of the resulting mixture? (hint: do
stoichiometry then Henderson-Hasselbach if appropriate)
vi) You add .040 moles of NaOH to 200 mL of the original acid what is the pH of the resulting mixture? (hint: do
stoichiometry then Henderson-Hasselbach if appropriate)
vii) You add .060 moles of NaOH to 200 mL of the original acid what is the pH of the resulting mixture? (hint: do
stoichiometry then Henderson-Hasselbach if appropriate)
31
Review Sheet #18 Acids (Contd.)
BUFFER PROBLEM
2. A buffer contains 0.40 moles of propanoic acid (C2H5COOH; MM = 62 g/mol) and 58 g of sodium
propanoate (NaC2H5CO2; MM= 96 g/mol) in enough water to make 100 mL of solution. What is the molarity of
propanoic acid (C2H5COOH) AND propanoate ion (C2H5CO21-)
i) Write-out the buffer equation
________________________________  _____________________________
ii) What is the pH of this solution?
iii) What is the pH when 0.15 moles of HCl is bubbled into 100. mL of the original buffer solution (assume no volume
change)
_________________________________ _____________________________
iv) What is the pH when 0.15 moles of NaOH is added to 100. mL of the original buffer solution (assume no volume
change)
_________________________________ _____________________________
v) If 100 mL of this buffer is diluted to a volume of 1.0 L with pure water, the pH does not change. Discuss why the pH
doesn’t change. What does change?
32
Review Sheet #19 Bases
Name__________________________ Per.______
1. A 0.05 molar solution of the weak base Aniline, C6H5NH2 has a pH of 8.651 at 25oC.
a) Write-out the Kb expression
b) Complete the ICE diagram for the ionization of Aniline, C6H5NH2
_________________________  __________________________
I
C
E
2. Methylamine, CH3NH2, is a weak base. The value of the ionization constant Kb, is 5.25 x 10-4.
i) Write out the ionization of methylamine in water and complete an ICE table, including
equilibrium concentrations for a 0.20 M solution of this base
__________________________________ __________________________________
I
C
E
ii ) Write out the Kb expression
Kb = _______________
iii) What is the percent ionization of the Methylamine, CH3NH2?
iv) Complete the table for this solution
pH:_______
POH________
[H3O1+]: ___________ [OH1-]:_____________
v) You add .010 moles of HCl to 100 mL of the original 0.20 Methylamine, CH3NH2 what is the pH of the resulting
mixture? (hint: do stoichiometry then Henderson-Hasslebach if appropriate)
33
Review Sheet #19 Bases (Contd.)
CONJUGATE WEAK ACID
3. i) Write-out the formula (with charge), give the name for conjugate acid, and identify the conjugate acid of the weak
base Dimethyamine, (CH3)2NH (Kb = 7.4 x 10-4)
Formula:___________________________
Name:______________________________
Ka of conjugate acid:
ii)
Write the correctly balanced net ionic equation for the reaction that occurs when the salt, dimethylammonium
chloride, (CH3)2NH2Cl is dissolved in water (HYDROLYSIS REACTION). The solution of dimethylammonium
chloride, (CH3)2NH2Cl is 0.30 M.
________________________________________ ______________________________________
I
C
E
ii) Write out the Ka expression for the hydrolysis reaction above:
iv) Complete the table for this solution
pH:_______
Ka = ________________
POH________
[H3O1+]: ___________ [OH1-]:_____________
BUFFER PROBLEM
4. i) 100 mL of buffer contains 0.60 moles of Dimethylamine, (CH3) 2 NH and 0.40 moles of Dimethlyammonium
chloride, (CH3)2NH2Cl). What is the pH of this solution?
ii) If 0.15 moles of HCl is added to 100. mL of the original buffer solution, what is the new pH?
(Stoichiometry and then Henderson-Hasslebach) Assume no volume change.
34
Review Sheet #20 Titrations & Buffers
Name______________________ Per. ______
1. Complete the tables below.
Buffer ( Y or N )
pH ( <7, >7, neutral)
0.5 M NaCl
_____________
_________________
0.5 M NH4Cl and
0.5 M NaOH
_____________
_________________
0.5 M NH4Cl and
0.5 M NH3
_____________
_________________
0.5 M HC2H3O2
_____________
_________________
_____________
_________________
_____________
_________________
_____________
_________________
_____________
_________________
0.5 M HCl
0.5 M HCl
and
and
0.5 M NaOH and
0.5 M HF
0.5 M KOH
and
0.5 M NaF
and
0.5 M C6H5NH
0.5 M NH3
0.5 M KCl
and
0.5 M C6H5NH2Cl
Solution Make-up
Description
______0.1 M NaOH and 0.1 M NaCl
a) Acidic Solution (NOT a buffer)
______0.1 M HOBr and 0.1 M KOBr
b) Acidic Solution (THAT IS a buffer)
______0.1 M NH4Br and 0.1 M NH3
c) Neutral Solution (THAT IS not a buffer)
______0.1 M HCl
and 0.1 M NaCl
d) Basic Solution (NOT a buffer)
______ 0.1M HCl
and
e) Basic Solution (THAT IS a buffer)
0.1 M NaOH
2. In an experiment to determine the molecular weight and the ionization constant for ascorbic acid (vitamin C), a
student dissolved 1.3717 grams of the acid in water to make 50.00 millilitres of solution. The entire solution was
titrated with a 0.2211 molar NaOH solution. The pH was monitored throughout the titration. The equivalence point
was reached when 35.23 millilitres of the base has been added. Under the conditions of this experiment, ascorbic
acid acts as a monoprotic acid that can be represented as HA.
(a) From the information above, calculate the molecular weight of ascorbic acid.
(b) When 20.00 millilitres of NaOH had been added during the titration, the pH of the solution was 4.23.
Calculate the acid ionization constant for ascorbic acid (Use Henderson Hasselbach)
35
Review Sheet #20 Titrations & Buffers (Contd.)
3. A 0.324 gram sample of an unknown weak monoprotic WEAK organic acid, HA was dissolved in sufficient water
to make 50 milliliters of solution and was titrated with a 0.135 molar NaOH solution. The equivalence point (end
point) was reached after the addition of 25.0 milliliters of the 0.135 molar NaOH. See the Titration Curve below:
(a) i.What is the formula of the salt formed during the titration?
ii. Was the salt formed acidic, basic, or neutral? Explain
Volume of 0.135 M NaOH Added
(b) i. What letter on the graph represents the “Equivalence or Stoichiometric” point?
ii. What letter on the graph represents the “Half-Equivalence” point?
________
iii. What species are present in the Erlenmeyer flask at point “U”?
iv. What species are present in the Erlenmeyer flask at point “V”?
________
_________ & ________
v. What species are present in the Erlenmeyer flask at point “X”?
vi. What species are present in the Erlenmeyer flask at point “Z”?
________
________
_________ & ________
(c) Circle the region on the Titration Curve where the best buffering would occur.
(d) i. Calculate the number of moles NaOH added at the equivalence point.
ii. Calculate the number of moles of acid (HA) in the original sample.
(e) Calculate the molecular weight of the acid HA (g/mol)
(f) What indicator would work best? Why
Methyl red
Cresol red
Alizarin yellow
Ka = 1x10-5
Ka = 1x10-8
Ka = 1x10-11
36
Review Sheet #21 Solubility Product (Ksp) Name_____________________ Per.
1. The solubility of CuI2 (MM= 317 g/mol) is 2.0 x10–6 molar. This is the molarity of a saturated solution of CuI2 at 25oC
a) Write-out the dissolution reaction and Ksp expression.
____________(s)  _____________________________ ΔHo = +10 kJ
Ksp= ___________________
b) Solve for Ksp
c) Is the solution colored? What color?
d) How many moles of CuI2 is in 250 mL of this solution? What is its mass?
e) i. What would be the solubility of CuI2 (s) in 0.25 M NaI?
i. What would be the solubility of CuI2 (s) in 0.25 M Cu (NO3)2?
f) 50.0 mL of a 0.005 M Cu (NO3)2 solution is mixed with 50.0 mL of 0.025 M NaI (aq)
i) What is the [Cu2+] when mixed? [I1-] when mixed?
ii) Calculate Qsp for the reaction
iii) Using your answer to Ksp and Qsp -- will a precipitate form? Explain
g) In terms of Le Chatelier’s principle, will more of less CuI2 dissolve at 50ºC? Explain.
37
Review Sheet #21 Solubility Product (Ksp) (Contd.)
2. At 25oC a saturated solution of a metal hydroxide Mg(OH)2, has a pH of 9.0.
a) Write-out the dissolution reaction and Ksp expression.
____________(s)  _____________________________
I
Ksp: ___________________
C
E
c)
Calculate the value of Ksp at 25oC.
c) Will this salt be more or less soluble in a solution of 0.10 M HCl. Justify using LeChatelier’s Principle.
3. The concentration of [Ag+] in a solution saturated with Ag2C2O4 (s) is 5.4 x 10-12 M.
a) Write-out the balanced equation for the solubility equilibrium and Ksp expression and completely fill in the
ICE diagram below?
______________  ____________________________ Ksp = _______________
I
C
E
b. Calculate Ksp for Ag2C2O4 (s).
c. i. Is this salt acidic, basic or neutral? Explain
ii. Will this salt be more soluble in an acid or base environment?
Explain using LeChatelier’s.
4. Silver phosphate, Ag3PO4 has a Ksp = 1.8 x 10-18
a) Write-out the balanced equation for the solubility equilibrium and the Ksp expression.
b.)What is the molarity (X) of a saturated solution of silver phosphate in moles / liter?
38
Review Sheet #21 Solubility Product (Ksp) (Contd.)
c) In a separate experiment, 500 ml of solution has a concentration of 1 x 10-6 M AgNO3.
i. What molarity of [Na3PO4] would you need to start precipitation of Ag3PO4 (s)
ii. What mass of Na3PO4 would you have needed to add to get this precipitation?
39
Review Sheet #22 Thermodynamics I
Name_____________________ Per.
Br2(l)  Br2(g) (Boiling)
1. At 25oC the equilibrium constant, Kp, for the reaction above is 0.281 atmosphere.
(a) What is the ΔGo 298 for this reaction? Explain
(b) It takes 193 joules to vaporize 1.00 gram of Br2(l) at 25oC and 1.00 atmosphere pressure. What are the values of ΔHo
o
298 and ΔS 298 for this reaction?
(c) Calculate the normal boiling point of bromine. Assume that ΔHo and ΔSo remain constant as the temperature is
changed (Remember at boiling Br2 (l) is in equilibrium with Br2 (g))
(d) What is the equilibrium vapor pressure of bromine at 25oC?
PCl5(g)  PCl3(g) + Cl2(g)
2. For the reaction above, ΔHo = +22.1 kilocalories per mole at 25oC
(a) Does the tendency of reactions to proceed to a state of minimum energy favor the formation of the products of this
reaction? Explain
(b) Does the tendency of reactions to proceed to a state of maximum entropy favor the formation of the products of this
reaction? Explain.
40
Review Sheet #22 Thermodynamics I (Contd.)
3. A rigid container holds a mixture of PCl5(g), PCl3(g), and Cl2(g) at equilibrium. State the direction the equilibrium
must move to re-establish equilibrium, whether the number of moles of PCl3(g) in the container (will increase, decrease,
or remain the same) and whether Keq (increases, decreases or remains the same) after each of the following disturbances
is applied to the original mixture. For each case, assume that all other variables remain constant except for the given
disturbance.
Direction
PCl3(g)
Equilibrium Constant
(i)
Decreasing the volume of the system.
________
_______________
______________
(ii)
Removing PCl5 (g) from the mixture.
________
_______________
______________
(iii)
Raising the temperature of the system.
________
_______________
______________
(iv)
A Ni catalyst is added
________
_______________
______________
(v)
Cl2 (g) is added to the mixture
________
_______________
______________
(vi)
He (g) is added to the mixture
________
_______________
______________
BCl3(g) + NH3(g)  Cl3BNH3(s)
4. The reaction represented above is a reversible reaction.
(a) Predict the sign of the entropy change, ΔSo, as the reaction proceeds to the right. Explain your prediction.
(b) If the reaction spontaneously proceeds to the right, predict the sign of the enthalpy change, ΔH o. Explain your
prediction.
(c) The direction in which the reaction spontaneously proceeds changes as the temperature is increased above a specific
temperature. Explain.
41
Review Sheet #23 Thermodynamics II
Name_______________________ Per.______
CH2CH2 + 3O2 CO2
For the reaction of ethylene represented above, ΔH is -1,323 kJ.
What is the value of ΔH if the combustion produced liquid water
H2O(l), rather than water vapor H2O(g) ? (ΔH for the phase
change H2O(g)  H2O(l) is –44 kJ mol-1.)
(A) -1,235 kJ
(B) -1,279 kJ
(D) -1,367 kJ
(E) -1,411 kJ
H2(g) + /2 O2(g)  H2O(l)
1
2 Na(s) + /2 O2(g)  Na2O(s)
1
(C) -1,323 kJ
ΔHo = –286 kJ
o
ΔH = –414 kJ
Na(s) + /2 O2(g) + /2 H2(g)  NaOH(s)
ΔHo = –425 kJ
Based on the information above, what is the standard
enthalpy change for the following reaction?
1
1
Na2O(s) + H2O(l)  2 NaOH(s)
(A) –1,125 kJ (B) –978 kJ (C) –722 kJ
(D) –150 kJ
(E) +275 kJ
N2(g) + 3 H2(g) 2 NH3(g)
The reaction indicated above is thermodynamically spontaneous
at 298 K, but becomes non-spontaneous at higher temperatures.
Which of the following is true at 298 K?
(A) ΔG, ΔH, and ΔS are all positive.
(B) ΔG, ΔH. and ΔS are all negative.
(C) ΔG and ΔH are negative, but ΔS is positive.
(D) ΔG and ΔS are negative, but ΔH is positive.
(E) ΔG and ΔH are positive, but ΔS is negative.
H2O(s)  H2O(l)
When ice melts at its normal melting point, 273.16 K
and 1 atmosphere, which of the following is true for
the process shown above?
a. H < 0, S > 0, V > 0
b. H < 0, S < 0, V > 0
c. H > 0, S < 0, V < 0
d. H > 0, S > 0, V >0
e. H > 0, S > 0, V < 0
When solid ammonium chloride, NH4Cl(s), is added to water at
25oC it dissolves and the temperature of the solution decreases.
Which of the following is true for the values of ΔH and ΔS for the
dissolving process? (A) Positive
Positive
(B)
Positive
Negative
(C)
Positive
Equal to zero
(D)
Negative
Positive
(E)
Negative
Negative
I2(g) + 3 Cl2(g)  2 ICl3(g)
According to the data in the table below, what is the value of ΔHo
for the reaction represented above?
Bond
Average Bond Energy
(kilojoules/mole)
I–I
149
Cl–Cl 239
I–Cl
208
(A) –860 kJ
(D) +450 kJ
(B) –382 kJ
(C) +180 kJ
(E) +1,248 kJ
A (g) + B(g) C (g)
The reaction indicated above is thermodynamically spontaneous
at 298 K, but becomes non-spontaneous at lower temperatures.
Which of the following is true at 298 K?
(A) ΔG, ΔH, and ΔS are all positive.
(B) ΔG, ΔH. and ΔS are all negative.
(C) ΔG and ΔH are negative, but ΔS is positive.
(D) ΔG is negative, but ΔH and ΔS are positive.
(E) ΔG and ΔH are positive, but ΔS is negative.
CH4(g) + 2 O2(g)  CO2(g) + 2 H2O(l)
ΔHo = –889.1 kJ
ΔHfo H2O(l) = –285.8 kJ/mol
ΔHfo CO2(g) = –393.3 kJ/mol
What is the standard heat of formation of methane, ΔH fo CH4(g),
as calculated from the data above?
(A) –210.0 kJ/mole
(B) –107.5 kJ/mole
(C) –75.8 kJ/mole
(D) 75.8 kJ/mole
(E) 210.0 kJ/mole
A cube of ice is added to some hot water in a rigid, insulated
container, which is then sealed. There is no heat exchange with
the surroundings. What has happened to the total energy and the
total entropy when the system reaches equilibrium?
Energy
Entropy
(A)
Remains constant
Remains constant
(B)
Remains constant
Decreases
(C)
Remains constant
Increases
(D)
Decreases
Increases
(E)
Increases
Decreases
42
Review Sheet #23 Thermodynamics II (Contd.)
1. Complete the matching below.
______Of the following reactions, which involves the largest decrease in entropy (ΔS>0)?
______Of the following reactions, which involves the largest increase in entropy (ΔS<0)?
______Of the following reactions, which involves a small if any change in entropy
(ΔS=0)?
2. a. Calculate the standard enthalpy change for the ΔHof of strontium carbonate (the material that gives the red color in fireworks).
 SrO (s)
 CO2 (g)
 SrCO3 (s)
ΔHo =
ΔHo =
ΔHo =
Reaction 1:
Reaction 3:
Reaction 2:
Sr (s) + ½ O2 (g)
C (graphite) + O2 (g)
SrO (s) + CO2 (g)
Desired:
____________________  _________________________
-590 kJ
-400 kJ
-250 kJ
ΔHo =________ kJ
b. Using your answer to party (a) what is are the ΔHo for the following reactions:
i.
SrCO3 (s)  Cgraphite + 3/2 O2 (g) +
ii.
2 Cgraphite + 3 O2 (g) + 2 Sr (s)  2 SrCO3 (s)
Sr (s)
ΔHo =________ kJ
ΔHo =________ kJ
3. Circle the species with the greatest entropy:
a. Dry ice (solid CO2) at -78oC
or
Dry ice (solid CO2) at -50oC
b. Liquid water at 25oC
or
liquid water at 50oC
c. 1 mole of N2 (g) at 1 atm
or
1 mole of Nbbbbbbbbbbbb at 10 atm (both at 298 K)
d. Pure Silicon
or
impure silicon
4. i. Predict the sign of So reaction =_______
2 NO (g) + O2 (g)
 2 NO2 (g)
ii. Calculate the actual So reaction
So NO2 = 240 J/K*mol
So NO = 211 J/K*mol
So O2 = 205 J/K*mol
iii. Calculate the actual Go reaction
GfoNO2= 51 kJ/mol
ΔGfoNO = 87 kJ/mol
GfoO2 = 0 kJ/mol
iv. Calculate the value of ΔHoreaction
v. Calculate Keq of the reaction
vi. What temperatures will this reaction be spontaneous (high, low, none, all) explain.
43
Review Sheet #24 Thermodynamics III
Name_____________________ Per.______
1. a) Classify the following reactions as: spontaneous under all conditions, only at lower temperatures, only at higher temperatures, or
at no temperatures. Also indicate whether the reactions are enthalpy driven, entropy driven, neither, or both.
Temperatures
Driving Force
(H, S, Both, None)
i) N2(g) + 3 F2 (g)  2 NF3 (g)
ΔHrxno= -264 kJ ΔSo = -278 J/K
_________
___________
ii) N2 (g) + 2 O2 (s)  2 NO2 (g)
ΔHrxno= + 66 kJ ΔSo = -120 J/K
_________
___________
iii) C6H12O6 (s) + 6 O2 (g)  6 CO2 (g) + 6 H2O (l)
ΔHrxno=
_________
___________
iv) MgO (s) + C (graphite)  Mg (s) + CO(g)
ΔHrxno= +490 kJ ΔSo = +200 J/K
_________
___________
c)
What is the value of ΔGo for reaction (i) above?
d)
What is the value of Kequilibrium
-673 kJ ΔS = +60 J/K
o
c) At what temperature does reaction reaction (i) become spontaneous? Will it be spontaneous at temperature greater or less than your
answer? Explain
d) At what temperature does reaction reaction (iv) become spontaneous? Will it be spontaneous at temperature greater or less than
your answer? Explain
2. Calcium carbonate is a common substance that decomposes upon heating.
CaCO3 (s)
H f
So
ΔGof
o
(a)
-1208 kJ/mol
92 J/K* mol
?

CaO (s)
+ CO2 (g)
-635 kJ/mol
38 J/k*mol
-603kJ/mol
-394 kJ/mol
214 J /K*mol
-394 kJ/mol
For the reaction above, find Hosys and Sosys .
44
Review Sheet #24 Thermodynamics III (Contd.)
(b) Indicate whether the reaction is enthalpy driven, entropy driven, neither, or both.
(c) Using your answers from part (a) calculate the Gorxn.
(d) Will this reaction occur spontaneously? Explain
(e) What is the Gof for CaCO3 (s)?
(f) What is the value of Kequilibrium for the reaction?
45