Download Fall 2006

Chemistry 120
Exam 1
September 25, 2006
Name __________________
SHOW YOUR WORK. NO WORK, NO CREDIT
INCLUDE LABELS AND PROPER NUMBER OF SIG FIGS
Up to 75% of the credit for a problem will be given for correctly setting it up, including labels on all numbers.
CONSTANTS AND EQUATIONS YOU MAY NEED
I PLEDGE ON MY HONOR THAT DURING THE EXAM I HAVE NEITHER GIVEN NOR RECEIVED ASSISTANCE NOR
HAVE I SEEN ANY DISHONEST WORK.
Signed __________________________________________________________________________
If you feel you can’t sign this, contact the instructor (e-mail or in person)
Multiple choice - circle the correct answer.
1.
(2 pt) What symbol (metric system prefix) is used to represent the factor 10-6?
a) n
2.
7.
b) sodium
b) carbon
b) 2
d) sulfur (S)
c) bromine
d) chlorine
c) arsenic
d) oxygen
c) 3
d) 4
(2 pt) If hitting the bull’s eye is the desired result, the figure on the right represents
a) poor accuracy and poor precision.
b) poor accuracy and good precision.
c) good accuracy and poor precision.
d) good accuracy and good precision.
(2 pt) Radium (88Ra) belongs to which group of the periodic table?
a) alkaline earth metals
8.
c) phosphorus (P)
(2 pt) How many significant figures are there in the answer for the following problem?
a) 1
6.
b) silicon (Si)
(2 pt) All of the following elements are nonmetals except
a) hydrogen
5.
d) m
(2 pt) Which of the following elements is a liquid at room temperature?
a) helium
4.
c) M
(2 pt) Which of the following elements has chemical properties similar to nitrogen?
a) boron (B)
3.
b) µ
b) halogens
c) alkali metals
d) noble gases
(2 pt) Which of the following numbers has the greatest number of significant figures?
a) 418000
b) 0.5070
c) 6.02 x 1023
d) 0.000201
1
23.1 + 0.5588 + 17 = ?
9.
(2 pt) Identify the chemical symbol of element Q in
a) Sc
10.
11.
13.
14.
c) Ca
.
d) this element doesn’t exist
(2 pt) Which statement about diluted solutions is false? When a solution is diluted
a) the molarity of the solution decreases.
b) the number of moles of solute remains unchanged.
c) the number of moles of solvent remains unchanged.
d) the concentration of the solution decreases.
(2 pt) Which one of the following compounds contains the smallest percent chlorine by mass?
a) Cl2
12.
b) K
40
19 Q
b) HCl
c) MgCl2
d) AuCl3
(2 pt) What group of elements does the shaded area in the following periodic table indicate?
a) alkali metals
b) alkaline earth metals
c) halogens
d) transition metals
(2 pt) Cherry Kool-Aid is an example of
a) a heterogeneous mixture
b) a compound
c) an element
d) a homogeneous mixture
(2 pt) To the correct number of significant figures, what is the temperature reading on the following Celsius thermometer?
___________________________
15.
(3 pts) What is the oxidation number (charge) on Cr in Na2CrO4? Explain your reasoning.
16.
(2 pts) If VO3-3 is called vanadate, what is the formula for pervanadate?
17.
(3 pts) Write the formula of the compound that results when UO2+2 combines with IO4-1.
18.
(3 pts each) Name the following compounds.
19.
a. N2O
________________________________
b. Zn(NO2)2
________________________________
(3 pts each) Write the formula for each of the following compounds.
a. copper (I) sulfite
________________________________
b. calcium nitride
________________________________
20.
(8 pts) The following diagram represents the reaction of A2 (small, unshaded spheres) with B (large,
shaded spheres). How many moles of product can be produced from the reaction of 1.0 moles of A2 and
1.0 moles of B? Explain your reasoning.
21.
(8 pts) A piece of metal ore weighs 9.00 g. When placed into a graduated cylinder containing water, the
liquid level rises from 21.25 mL to 26.47 mL. What is the density of the ore?
22.
(6 pts) Why is it NOT a good idea to store coats and bookbags on the lab benches in lab?
2
23.
(8 pts) One type of cordless phone operates on a frequency of 800 MHz. What is the wavelength of this radiation?
24.
(8 pts) A typical C-Cl bond requires 330 kJ/mole of energy to break the bond. What frequency of light has photons with just enough
energy to break this bond?
25.
Lead chloride reacts with phosphoric acid in aqueous solution by the following reaction:
Pb(NO3)2 + H3PO4 ! Pb3(PO4)2 + HNO3
a. (6 pts) Balance the reaction.
b. (8 pts) The Pb3(PO4)2 is not soluble in the water, so it can be recovered by filtration. In an experiment a student mixed 50.00 mL
of 0.1000 M H3PO4 with an excess of Pb(NO3)2 and recovered 1.3x10-3 moles of solid Pb3(PO4)2, what is the percent yield for this
reaction?
Chemistry 120
Exam 2
October 16, 2006
Name __________________
SHOW YOUR WORK. NO WORK, NO CREDIT
INCLUDE LABELS AND PROPER NUMBER OF SIG FIGS
Up to 75% of the credit for a problem will be given for correctly setting it up, including labels on all numbers.
CONSTANTS AND EQUATIONS YOU MAY NEED
AX2
AX3
AX2E
AX4
AX3E
AX2E2
linear
trigonal planar
bent
tetrahedral
trigonal pyramid
bent
AX5
AX4E
AX3E2
AX2E3
trigonal bipyramid
see saw
T
linear
AX6
AX5E
AX4E2
AX3E3
AX2E4
octahedral
square pyramid
square planar
T
linear
I PLEDGE ON MY HONOR THAT DURING THE EXAM I HAVE NEITHER GIVEN NOR RECEIVED ASSISTANCE NOR
HAVE I SEEN ANY DISHONEST WORK.
Signed __________________________________________________________________________
If you feel you can’t sign this, contact the instructor (e-mail or in person)
3
Circle the correct answer:
1.
(2 pts) Reaction of A (unshaded spheres) with B2 (shaded spheres) is shown schematically in the following diagram. Which equation
best describes the stoichiometry of the reaction?
a) 16 A + 4 B2 ! 8 A2B
2.
b) 45Rh
d) period 3 group 6
c) 8
d) 2n
(2 pts) Which block of elements, represents the f-block elements?
A
(2 pts) How many electrons can a single orbital hold?
b) 2
b) LiBr2
c) Li2Br3
b) 17Cl
c) 50Sn
b) sphere (b)
c) sphere (c)
B
d) LiBr3
d) 53I
d) sphere (d)
(2 pts) Which of the following are allowed resonance forms of NCS-1?
a) I
b) II
c) III
C
d) D (chickenwire)
(2 pts) The spheres in the figure represent atoms of Li, Be, B, and F (not
necessarily in that order). Which one of these spheres represents an atom of B?
a) sphere (a)
9.
c) C (shaded)
(2 pts) Which of the atoms below has the lowest ionization energy?
a) 13Al
8.
b) B (X’ed)
(2 pts) What compound is formed when 3Li + 35Br2 are mixed.
a) LiBr
7.
d) 64Gd
c) period 3 group 4
a) A (crosshatch)
6.
c) 43Tc
b) period 6 group 3
a) 2l + 1
5.
d) 4 A + 2 B ! 4 A4B2
(2 pts) An element that has the valence electron configuration 3s2 3p4 belongs to which period and group?
a) period 3 group 3
4.
c) 4 A + B2 ! 8 A2B
(2 pts) Which element has the ground-state electron configuration [Kr]5s2 4d7
a) 27Co
3.
b) 4 A + B2 ! A4B2
d) I and III
4
D
10.
(2 pts) What is the H-N-H bond angle in NH3 (Lewis Structure
shown)?
a) 90°
11.
b) 109.5°
c) 120°
13.
14.
b) trigonal planar
c) trigonal pyramid
d) bent
(2 pts each) Name the following compounds.
a. SO2
________________________________
b. HgSO4
________________________________
(2 pts each) Write the formula for each of the following compounds.
a. ammonium perchlorate
________________________________
b. arsenic (III) sulfide
________________________________
(3 pts) Which is the smallest ion P-3, S-2, Cl-1? Explain your reasoning.
a) P-3
15.
H N H
d) 180°
(2 pts) What is the shape of a molecule that is an sp3 hybrid with one lone pair of electrons around the central atom?
a) linear
12.
H
b) S-2
c) Cl-1
d) all the same size
(6 pts) What is the formal charge on the oxygen in the resonance form of SOCl2 shown.
O
Cl
16.
(6 pts each) Draw Lewis structures, including any resonance forms, for NO2-1 and XeF2.
17.
(1 pt each) Fill in the blanks for each structure
Cl
N
Cl
S
O
Cl
O C
H
Molecular Shape _______________________
Molecular Shape _______________________
Polar (yes/no)? _______________________
Polar (yes/no)? _______________________
F
F
H
Se H
Xe F
F
18.
Molecular Shape _______________________
Molecular Shape _______________________
Polar (yes/no)? _______________________
Polar (yes/no)? _______________________
(6 pts) Label the following binary compounds as ionic, polar covalent, or purely covalent. Then explain your reasoning.
NO ______________
19.
LiI ______________
N2 ______________
(8 pts) Write the electron configuration for 80Hg. You may start with an inert gas core if you wish.
5
20.
(8 pts) The electron configuration for 44Ru is [Kr] 5s2 4d6. Is +1 expected to be a stable charge for Ru? Explain your reasoning.
21.
(5 pts) Which Lewis Structure below cannot exist as a real molecule? Explain your reasoning.
Br
I
Br
Br
Br
Cl
Br
Br
Br
F
Br
Br
22.
(6 pts) While working in the lab you accidentally drop a 250 mL reagent bottle of 6 M NaOH and it shatters on the floor. You make
a quick check of yourself and find no evidence of splashes or cuts. What should you do next?
23.
(8 pts) An isotopically enriched sample of oxygen is 80.00% 16O (atomic mass 15.943 amu) and 20.00%
17.986 amu). What is the average atomic mass of oxygen in this sample?
Chemistry 120
18
O (atomic mass
Exam 3
Name __________________
November 6, 2005
SHOW YOUR WORK. NO WORK, NO CREDIT
INCLUDE LABELS AND PROPER NUMBER OF SIG FIGS
Up to 75% of the credit for a problem will be given for correctly setting it up, including labels on all numbers.
IONS
Group I metals and NH4+
Nitrates, Acetates, Perchlorates
Fluoride
Chlorides, Bromides, and Iodides
Sulfates
Other anions
Soluble/Insoluble
soluble
soluble
soluble
soluble
soluble
insoluble
6
Exceptions
none
none
Group II
silver, lead, mercury(I)
strontium, barium, lead
Group I and ammonium salts,
Group II sulfides,
barium oxide & hydroxide,
strontium oxide & hydroxide
AX2
AX3
AX2E
AX4
AX3E
AX2E2
linear
AX5
trigonal bipyramid
AX6
trigonal planar
AX4E
see saw
AX5E
bent
AX3E2
T
AX4E2
tetrahedral
AX2E3
linear
AX3E3
trigonal pyramid
AX2E4
bent
Enthalpies of Formation (∆Hf) for Selected Species
C10H22 (l)
-59.67 kJ/mole
HC2H3O2 (l) -484.5 kJ/mole
CO (g)
C3H8 (g)
-105 kJ/mole
H2O (g)
-241.8 kJ/mole
CO2 (aq)
+49.0 kJ/mole
H2O (l)
-285.8 kJ/mole
CO2 (g)
C6H6 (l)
C6H12O6
-1260 kJ/mole
H2O2 (l)
-187.8 kJ/mole
O (g)
CH3OH (l)
-238.7 kJ/mole
NH3 (g)
-46.1 kJ/mole
O2 (g)
NH3 (aq)
-80.3 kJ/mole
O3 (g)
C2H5OH (l) -277.7 kJ/mole
octahedral
square pyramid
square planar
T
linear
-110.5 kJ/mole
-413.8 kJ/mole
-393.5 kJ/mole
+249.2 kJ/mole
0 kJ/mole
+143 kJ/mole
I PLEDGE ON MY HONOR THAT DURING THE EXAM I HAVE NEITHER GIVEN NOR
RECEIVED ASSISTANCE NOR HAVE I SEEN ANY DISHONEST WORK.
Signed __________________________________________________________________________
If you feel you can’t sign this, contact the instructor (e-mail or in person)
1.
(2 pts) What volume of a 0.500 M NaOH solution contains 0.0125 mole of NaOH?
a) 0.00625 L
2.
4.
6.
d) 0.0250 L
b) 3
c) 2
d) none of these
(2 pts) If the percent yield for the following reaction is 65.0%, how many moles of KClO3 are needed to actually collect 6.00
moles of O2?
2 KClO3 ! 2 KCl + 3 O2
a) 6.00 * 0.650 * (3/2) moles KClO3
b) (6.00/0.650) * (3/2) moles KClO3
c) 6.00 * 0.650 * (2/3) moles KClO3
d) (6.00/0.65) * (2/3) moles KClO3
(2 pts) Three different substances, AX2, AY2, and AZ2, were
dissolved in water in separate beakers with the results shown in the
diagram. (Water molecules are omitted for clarity.) Which of the
substances is the strongest electrolyte?
a) AX2
5.
c) 0.006250 L
(2 pts) Strontium phosphate reacts with sulfuric acid to form strontium sulfate and phosphoric acid. What is the coefficient
for sulfuric acid when the equation is balanced using the lowest, whole-numbered coefficients?
a) 1
3.
b) 0.025 L
b) AY2
c) AZ2
d) all the same
AX2
AY2
(2 pts) Predict the products of a reaction between Ba(NO3)2 (aq) and K2SO4 (aq).
a) BaSO3 (s) and KNO2 (aq)
b) BaSO4 (s) and KNO3 (aq)
c) BaSO4 (aq) and KNO3 (aq)
d) Ba(SO4)2 (s) and K2NO3 (aq)
(2 pts) The reaction of HNO3 + KOH ! KNO3 + H2O is best classified as a(n)
a) precipitation reaction
b) acid base reaction
c) redox reaction
7
d) synthesis reaction
AZ2
(2 pts) If the concentration of Na+1 ions (black spheres) in the funnel
is 0.120 M and the volumes in the funnel and flask are the same,
what is the molarity of the I3-1 (grey spheres) in the flask?
(Oppositely charged ions in each container are omitted for clarity).
7.
a) 4.00 M
b) 0.120 M
c) 0.0400 M
d) 0.360 M
(2 pts) What reagent could be used to separate Cl-1 from C2H3O2-1
when added to an aqueous solution containing both?
8.
a) NaI (aq)
9.
b) AgNO3 (aq)
c) CuSO4 (aq)
d) Ba(OH)2 (aq)
(2 pts) Which of the following compounds is insoluble in water?
a) CaCO3
10.
b) NaNO2
c) H2SO3
d) ZnCl2
(2 pts) What is the balanced net ionic equation for the reaction of AgNO3 (aq) with Cu (s).
a) Ag+1 (aq) + Cu (s) ! Ag (s) + Cu+2 (aq)
b) 2 AgNO3 (aq) + Cu (s) ! 2 Ag (s) + Cu(NO3)2 (aq)
c) AgNO3 (aq) + Cu (s) ! Ag (s) + CuNO3 (aq)
d) 2 Ag+1 (aq) + Cu (s) ! 2 Ag (s) + Cu+2 (aq)
11.
(2 pts) What is the change in oxidation number (charge) for the chromium in the following unbalanced reduction half
reaction?
Cr2O7-2 + H+ ! Cr+2 + H2O
a) 6
12.
b) strong bases
b) + 1554 kJ/mole C2H6
b) diagram (3)
d) weak electrolytes
c) + 259 kJ
d) -259 kJ
c) diagram (4)
d) none
(2 pts) Which of the following compounds is a weak base?
a) NH3
16.
c) strong electrolytes
(2 pts) You have a sample of gas in a cylinder with a moveable
piston as shown in diagram (1). The initial pressure, number of
moles, and temperature of the gas are noted on the diagram. Which
diagram (2)-(4) most closely represents the position of the piston
when the pressure and the number of moles of gas are both doubled
while keeping the temperature constant?
a) diagram (2)
15.
d) 8
(2 pts) At constant pressure, the exothermic combustion of 0.1667 mole of C2H6 (g) releases 259 kJ of heat. What is ∆H for
the reaction (below)?
2 C2H6 + 7 O2 ! 4 CO2 + 6 H2O
a) -1554 kJ/mole C2H6
14.
c) 5
(2 pts) HBr, HI, HNO3, NaBr, and KNO3 are all classified as
a) strong acids
13.
b) 4
b) H2SO4
c) Na2O
d) CH3Cl
(2 pts) Which metal is the best heat conductor (specific heat in
parentheses)?
a) Al (0.90 J/g·deg)
b) Cu (0.39 J/g·deg)
c) Pb (0.16 J/g·deg)
8
d) Sn (0.222 J/g·deg)
17.
(2 pts each) Name the following compounds.
________________________________
a. HNO2
b. SnI4
________________________________
c. HF
18.
________________________________
(2 pts each) Write the formula for each of the following compounds.
a. hydrosulfuric acid
________________________________
b. arsenic (V) hydride
________________________________
c. carbonic acid
________________________________
19.
(8 pts) What is the total pressure in a 10.0 L flask which contains 0.288 mol of N2 (g) at 20.0°C?
20.
(9 pts) Balance the following redox reaction that takes place in acidic solution.
ClO4-1
21.
+
NH4+1
!
Cl-1
+
N2
(9 pts) Write and balance the net ionic equation.
HNO3 + K2SO3 ! KNO3 + H2SO3
22.
(6 pts) In lab the class is running a series of reactions that use several potentially hazardous chemicals. Groups are working
on the lab benches and are scattered throughout the lab (typical situation for our lab). Your group has finished the
experiment earlier than those groups around you. Is it OK for your group to remove your safety goggles to work on
calculations at your lab desk while the others finish the lab? Explain your reasoning.
23.
(9 pts) Calculate the ∆H for the reaction below using the ∆Hf values on the front page.
3 C3H8 (g) + 10 O3 (g) ! 9 CO2 (g) + 12 H2O (g)
24.
(8 pts) When 0.0153 mole of KNO3 is dissolved in 100.0 g of H2O, 533.8 J of heat is absorbed from the surroundings. What
is the enthalpy of solution (∆Hsoln) for KNO3?
25.
(7 pts) The ∆H for a particular reaction is 18.3 kJ/mole and the ∆S is 50.0 J/mole·K. Is the reaction spontaneous at 300K?
Explain your reasoning.
9
Chemistry 120
Exam 4
November 29, 2006
SHOW YOUR WORK. NO WORK, NO CREDIT
Name __________________
INCLUDE LABELS AND PROPER NUMBER OF SIG FIGS
Up to 75% of the credit for a problem will be given for correctly setting it up, including labels on all numbers.
IONS
Soluble/Insoluble
Exceptions
soluble
none
Group I metals and NH4+
Nitrates, Acetates, Perchlorates
soluble
none
Fluoride
soluble
Group II
Chlorides, Bromides, and Iodides
soluble
silver, lead, mercury(I)
Sulfates
soluble
strontium, barium, lead
Other anions
insoluble
Group I and ammonium salts,
Group II sulfides,
barium oxide & hydroxide,
strontium oxide & hydroxide
AX2
linear
AX5
trigonal bipyramid
AX6
octahedral
trigonal planar
AX4E
see saw
AX5E
square pyramid
AX3
AX2E
bent
AX3E2
T
AX4E2
square planar
AX4
tetrahedral
AX2E3
linear
AX3E3
T
trigonal pyramid
AX2E4
linear
AX3E
AX2E2
bent
Enthalpies of Formation (∆Hf) for Selected Species
C10H22 (l)
-59.67 kJ/mole
HC2H3O2 (l) -484.5 kJ/mole
CO (g)
-110.5 kJ/mole
-105 kJ/mole
H2O (g)
-241.8 kJ/mole
CO2 (aq) -413.8 kJ/mole
C3H8 (g)
C6H6 (l)
+49.0 kJ/mole
H2O (l)
-285.8 kJ/mole
CO2 (g)
-393.5 kJ/mole
C6H12O6
-1260 kJ/mole
H2O2 (l)
-187.8 kJ/mole
O (g)
+249.2 kJ/mole
-238.7 kJ/mole
NH3 (g)
-46.1 kJ/mole
O2 (g)
0 kJ/mole
CH3OH (l)
C2H5OH (l) -277.7 kJ/mole
NH3 (aq)
-80.3 kJ/mole
O3 (g)
+143 kJ/mole
I PLEDGE ON MY HONOR THAT DURING THE EXAM I HAVE NEITHER GIVEN NOR
RECEIVED ASSISTANCE NOR HAVE I SEEN ANY DISHONEST WORK.
Signed __________________________________________________________________________
If you feel you can’t sign this, contact the instructor (e-mail or in person)
10
1.
(2 pts) Which figure best indicates the direction of the dipole moment in acetone, (CH3)2C=O?
2.
(2 pts) In pure liquid methanthiol, CH3SH, which intermolecular forces are present?
a) Dipole-dipole and ion-dipole forces are present.
b) Dispersion, hydrogen bonding and dipole-dipole forces are present.
c) Only hydrogen bonding forces are present.
d) Dispersion and dipole-dipole forces are present.
3.
(2 pts) Which of the following has the largest dipole moment?
a) KCl
4.
b) H-H
d) CH3F
(2 pts) Which of the following compounds exhibits hydrogen bonding?
a) CH3F
5.
b) H2S
c) H3C-O-CH3
d) CH3CH2NH3
(2 pts) Which compound has the lowest boiling point?
a) CH3CH2OH
6.
7.
c) O=C=O
b) CH3CH2CH3
c) H3C-O-CH3
d) CH3CH2NH3
(2 pts) Which should be least soluble in water?
a)
b)
c)
d)
(2 pts) One reason ionic compounds do not dissolve well in nonpolar solvents is that
a) not all cations and anions have the same magnitude of charge and therefore do not form neutral ion pairs.
b) ion-dipole interactions are too large for effective solvation to occur.
c) ion-solvent interactions are not strong enough to solvate the ions in solution.
d) there are no forces of attraction between ions and nonpolar molecules.
11
8.
(2 pts) Which of the intermolecular forces is the most important contributor to the high surface tension shown by water?
a) dipole-dipole forces
9.
b) ion-dipole forces
c) hydrogen bonding
d) dispersion forces
(2 pts) Molecules of a liquid can pass into the vapor phase only if the
a) liquid has little surface tension.
b) vapor pressure of the liquid is high.
c) temperature of the liquid is near its boiling point.
d) molecules have sufficient kinetic energy to overcome the intermolecular forces in the liquid.
10.
(2 pts) What is the equilibrium constant expression (Ka) for the acid dissociation of nitrous acid HNO2?
a) Ka = ([H3O+1][NO2-1])/([HNO2])
b) Ka = ([H3O+1][NO2-1])/([HNO2][H2O])
c) Ka =([HNO2][H2O])/([H3O+1][NO2-1])
d) Ka = ([HNO2])/([H3O+1][NO2-1])
11.
(2 pts) Picture (1) represents the equilibrium mixture for the endothermic reaction A + B W 2 AB at 298 K. Which picture
represents the equilibrium mixture at 400 K?
a) (2)
12.
b) (3)
c) (4)
d) none of them
(2 pts) In an experiment to study the equilibrium shown below, known amounts of H2, N2, and NH3 were added to a sealed
flask and the mixture allowed to come to equilibrium. At the end of the experiment it was found that the amount of NH3
had increased. Which statement is true about this experiment?
3 H2 (g) + N2 (g) W 2 NH3 (g)
a) Keq = Q
13.
b) Keq > Q
d) More information is needed to make a statement about Keq.
(2 pts) Which compound is acidic?
a) NaC2H3O2
14.
c) Keq < Q
b) NaCl,
c) NH4Cl
d) C2H6
(2 pts) Of these weak acids, which is the strongest?
a) HF with Ka = 3.5 x 10-4
b) HC2H3O2 with Ka = 1.8 x 10-5
c) HC7H5O2 with Ka = 6.5 x 10-5
d) HClO with Ka = 3.5 x 10-8
15.
(2 pts) What is the hydronium ion concentration of an acid rain sample that has a pH of 3.35?
a) 2.24 x 10-11 M
16.
b) 0.525 M
c) 3.35 M
d) 4.47 x 10-4 M
(2 pts) Which one of the following can behave either as a Brønsted-Lowry acid or base in an aqueous solution?
a) H3PO4
b) HI
c) HSO3-1
d) NH3
12
17.
(2 pts) What statement is most consistent for an acid with a pH = 3?
a) It is twice as strong as an acid with a pH of 6.
b) It is half a strong as an acid with a pH = 6
c) It is one thousandth as strong an acid with a pH of 6.
d) It is one thousand times as strong as an acid with a pH = 6.
18.
19.
20.
(3 pts each) Name the following compounds.
a. H3PO2
________________________________
b. NO2
________________________________
(3 pts each) Write the formula for each of the following compounds.
a. potassium dichromate
________________________________
b. bromous acid
________________________________
Consider the equilibrium mixture:
Pb(ClO)2 (s) + 2 H2O (l)
W
Pb+2 (aq) + 2HClO (aq) + 2 OH-1 (aq)
a. (10 pts) Write the equilibrium constant expression for the following reaction
Keq =
b. (9 pts) If a few drops of 0.3 M Pb(NO3)2 were added to 1 mL of the equilibrium mixture in a test tube, would the amount
of precipitate (reactant) increase, decrease, or stay the same? Explain your reasoning.
21.
(5 pts) During a particular lab you are heating a solution with a bunsen burner. Someone working across the desk from you
pushes their book bag out of their road. In a few moments you notice that it has gotten too close to your burner and is
burning brightly. If you are in our lab (GSC 243), where would you find a fire extinguisher?
22.
(10 pts) An aqueous solution is 17.75% sulfuric acid, H2SO4. If the density of the solution is 1.1094 g/mL, what is the
molarity?
23.
(10 pts) What is the pH of a 0.020 M Ba(OH)2 solution?
24.
(10 pts) Calculate the pH for 0.500 M HCN (Ka = 4.9 x 10-10)?
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