Consider the following information about the diprotic acid, ascorbic acid. (H2As for
short, molar mass 176.1)
H2As HAs–+ H+pKa= 4.10 (Ka= 7.9×10-5)
HAs– As2-+ H+pKa= 11.79 (Ka= 1.6×10-12)
The titration curve for disodium ascorbate, Na2As, with standard HCl is shown below:
What is the pH at point I (V1/2 HCl added)?
A) 4.10
B) 7.95
C) 11.79
D) 12.39
E) none of these
The reaction:
2A + B –> C
has the following proposed mechanism:
If step 2 is the rate-determining step, then the rate of formation of C should equal:
A)k[A]
B)k[A]2[B]
C)k[A]2[B]2
D)k[A][B]
E)k[A][B]2
For the reaction, X + Y –> A + B, Gois -1324 kJ. Which one of the following
statements is NOT valid concerning the reaction?
A) The reaction is thermodynamically favorable.
B) The reaction is spontaneous as written.
C) The products are more stable than the reactants.
D) The reaction will proceed rapidly from left to right.
E) Three of these statements are valid.
When comparing Be2and H2:
I.Be2is more stable because it contains both bonding and antibonding valence electrons.
II.H2has a higher bond order than Be2.
III.H2is more stable because it only contains s1selectrons.
IV.H2is more stable because it is diamagnetic, whereas Be2is paramagnetic.
A)I, II
B)III only
C)II, III
D)II, III, IV
E)III, IV
How many of the following will raise the pH of a weak acid HA in aqueous solution?
A) 1
B) 2
C) 3
D) 4
E) 5
Here are some crystal field representations of d electrons in an octahedral complex:
Choose the representation that fits the transition metal atom in the following species:
K4Fe(CN)6
A) representation I
B) representation II
C) representation III
D) representation IV
E) representation V
What is the best answer to report for g/mL?
A)
B)
C)
D)
E)
Which is the stronger acid in each of the following pairs?
I.HClO2or HClO3
II.H2S or H2Se
III.H3AsO4or H2SeO4
A) I. HClO3II. H2S III. H2SeO4
B) I.HClO2II. H2SIII. H2SeO4
C) I. HClO3II. H2SeIII. H3AsO4
D) I. HClO2II. H2SeIII. H3AsO4
E) I. HClO3II. H2SeIII. H2SeO4
Which of the following intermolecular forces exist in all solid substances?
A)Dispersion forces
B)Dipole–dipole forces
C)Covalent bonding
D)Hydrogen bonding
E)Ion–induced dipole forces
Using the following data to calculate Kspfor PbSO4.
A) 4.0 x 10106
B) 2.5 x 10-107
C) 5.9 x 107
D) 1.7 x 10-8
E) None of these is within 5% of the correct answer.
Tetracyanoethylene has the skeleton shown below:
From its Lewis structure determine the following:
How many of the atoms are sp2hybridized?
A)2
B)4
C)6
D)8
E)10
Predict the sign of S° for each of the following processes:
I.2 K(s) + Cl2(g) –> 2 KCl(s)
II.CH4(g) –> C(s) + 2 H2(g)
III.CaCO3(s) –> CaO(s) + CO2(g)
A) negative, negative, positive
B) negative, negative, negative
C) positive, negative, negative
D) negative, positive, positive
E) positive, positive, positive
Which of these solutions 0.1 m NaCl, 0.15 m glucose, 0.1 m CaCl2would have
I. the highest vapor pressure
II. the highest boiling point
A)0.1 m CaCl2, 0.1 m CaCl2
B) 0.15 m glucose, 0.1 m CaCl2
C)0.1 m CaCl2, 0.15 m glucose
D)0.15 m glucose, 0.15 m glucose
E)0.1 m NaCl, 0.1 m CaCl2
Refer to the galvanic cell below (the contents of each half-cell are written beneath each
compartment):
The standard reduction potentials are as follows:
What is the value of Q, the reaction quotient, for this cell reaction?
A) 6.7 x 1040
B) 1.5 x 10-41
C) 1.5 x 10-4
D) 6.7 x 103
E) none of these
Describe the relationship between pentane and 2-methylpentane
A) optical isomers
B) structural isomers
C) geometric isomers
D) not isomers but different compounds
E) same compound
What must be true about DG for this reaction?
A) G = H
B) G = 0
C) G > 0
D) G < 0
E) G = Suniv
When solutions of carbonic acid and aluminum hydroxide react, which of the following
are NOT present in the net ionic equation?
I.hydrogen ion
II.carbonate ion
III.aluminum ion
IV.hydroxide ion
A)I and II
B)I, II, and III
C)I and IV
D)I and III
E)II and III
Write molecular equations for the following reactions:formation of propyl propanoate
Consider the following data:
DH° (kJ)
Ca(s) + 2C(graphite) –> CaC2(s)-62.8
Ca(s) + O2(g) –> CaO(s)-635.5
CaO(s) + H2O(l) –> Ca(OH)2(aq)-653.1
C2H2(g) + O2(g) –> 2CO2(g) + H2O(l)-1300
C(graphite) + O2(g) –> CO2(g)-393.51
Use Hess’ law to find the change in enthalpy at 25°C for the following equation:
CaC2(s) + 2H2O(l) –> Ca(OH)2(aq) + C2H2(g)
CH4(g) + 4Cl2(g) –> CCl4(g) + 4HCl(g), DH = -434 kJ
Based on the above reaction, what energy change occurs when 1.2 moles of methane
(CH4) reacts?
How much heat is liberated at constant pressure when 2.35g of potassium metal reacts
with 5.68mL of liquid iodine monochloride (d = 3.24 g/mL)?
2K(s) + ICl(l) –> KCl(s) + KI(s)DH° = -740.71 kJ/mol
Green light can have a wavelength of 543nm. The energy of a photon of this light is
A general reaction written as A + 2B –> C + 2D is studied and yields the following
data:
Determine the initial rate of C production ( [C]/ t) if [A] = 0.200 M and [B] = 0.500
M.
The half-life for this experiment is
Calculate the number of nitrogen atoms in 240. g of ammonium nitrate.
The calcium atom is much larger than the calcium ion, while the fluorine atom is much
smaller than the fluorine ion. Explain this natural occurrence.
A cation has a larger proton to electron ratio than the corresponding neutral atom, so the
remaining electrons are more closely held. An anion has a smaller proton to electron
ratio than its corresponding neutral atom, so the electrons can not be held as closely.
Consider the graph below to answer the next two questions:
Explain the ionization energy difference between sodium and potassium.
CBrI3