AP CHEM FINAL (MC)
Permanganate and oxalate ions react in an acidified solution according to the balanced equation below. How many moles of CO2(g) are produced when 20. mL of acidified 0.20 M KMnO4 solution is added to 50. mL of 0.10 M Na2C2O4 solution?
0.010 mol
A 360. mg sample of aspirin, C9H8O4, (molar mass of 180. g), is dissolved in enough water to produce 200. mL of solution. What is the molarity of aspirin in a 50. mL sample of this solution?
0.0100 M
A 40.00mL sample of 0.25 M KOH is added to a 60.0mL of 0.25 M KOH is added to 60.0 mL of 0.15 M Ba(OH)2. What is the molar concentration of OH- (aq) in the resulting solution?
0.28 M
How many carbon atoms are contained in 2.8g of C2H4?
1.2x10^23
How many mL of 10.0 M HCl are needed to prepare 500. mL of 2.00 M HCl?
100. mL
A flask contains 0.25 mole of SO2 (g), 0.50 mole of CH4(g) and 0.50 mole of O2(g). The total pressure of the gases in the flask is 800mm Hg. What is the partial pressure of SO2(g) in the flask?
160 mm Hg
In which reaction is a single species both oxidized and reduced?
2 H2O2(l)-->O2(g)+2 H2O(l)
In the reaction represented below, what mass of HF is produced by the reaction of 3.0x10^23 molecules of H2 with excess F2, assuming the reaction moves to completion? H2+F2--> 2 HF
20. g
Based on the periodic trends and the data in the table below, which of the following are the most probable values of the atomic m=radius and the first ionization energy for potassium, respectively?
242 pm, 419 kJ/mol
The students determined that the reaction produced 0.010 mol of Cu(NO3)2. Based on the measurement, what was the percent of Cu by mass in the original 2.00g sample of the mixture?
32%
A student wishes to prepare 2.00 liters of 0.100-molar KIO3 (molecular weight 214). The proper procedure is to weigh out
42.8 gramps of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters
In a one-person spacecraft, an astronaut exhales 880g of CO2(g) (molar mass 44 g/mol) per day. To prevent the buildup of CO2 (g) in the spacecraft, a device containing LiOH(s) (molar mass 24g/mol) is needed to react with all of the CO2(g) produced by an astronaut in one day?
960g
How is the exothermic process represented best classified?
A chemical change because covalent bonds are broken and new covalent bonds are formed.
Of the elements listed, which has the highest electronegativity?
Br
On the basis of strength of intermolecular forces, which of the following elements would be expected to have the highest melting point?
Br2
Which choice represents the reaction between a Bronsted-Lowry acid and Bronsted-Lowry base?
C2H3O2-(aq) + H3O+(aq)--> HC2H3O2(aq)+H2O(l)
Sodium chloride is LEAST soluble in which of the following liquids?
CCl4
Pi bonding occurs in each of the following species EXCEPT
CH4
A 2 L container will hold about 4 g of which of the following gases at 0C and 1 atm?
CO2
Which of the following is a nonpolar molecule that contains polar bonds?
CO2
Of the elements listed, which has the largest atomic radius?
Cs
Of the elements listed, which has the lowest first-ionization energy?
Cs
Which of the following compounds at 25C and 1.0 atm contains an element in a +1 oxidation state?
Cu2O
The London dispersion forces are weakest for which of the following gases under the same conditions of temperature and pressure?
H2
Of the molecules below, which has the largest dipole moment? a) PH3 b) H2O c) CH4 d) C2H4
H2O
The Lewis Diagram for which of the following molecules would have two unshared pairs of electrons on the central atom?
H2S
The liquified hydrogen halides have the normal boiling points given below. The relatively high boiling point of HF can be correctly explained by which of the following?
HF molecules tend to form hydrogen bonds
According to the VSEPR model, the progressive decrease in the bond angles in the series of molecules CH4, NH3 and H2O is best accounted for by?
Increasing number of unshared pairs of electrons
Two pure elements react to form a compound. One element is an alkali metal, X, and the other element is a halogen, Z. Which of the following is the most valid scientific claim that can be made about the compound?
It contains ionic bonds
Which of the following correctly indicated whether the solid represented by the particulate model shown below conducts electricity and explains why or why not?
It does not conduct electricity because its ions cannot move freely within the solid
Each student in a class placed a 2.00g sample of a mixture of Cu and Al in a beaker and placed the beaker in a fume hood. The students slowly poured 15.0 mL of 15.8 M HNO3(aq) into their beakers. The reaction between the copper in the mixture and the HnO3(aq) is represented by the equation below. The students observed that a brown gas was released from the beakers and that the solutions turned blue, indicating the formation of Cu2+(aq). The solutions were then diluted with distilled water to known volumes. Which of the following is true about the reaction?
It is a redox reaction, because Cu(s) is oxidized and the nitrogen atom in NO3- (aq) is reduced.
A compound contains 1.10 mol of K, 0.55 mol of Te, and 1.65 mol of O. What is the simplest formula of this compound?
K2TeO3
A student has a 1g sample of each of the following compounds: NaCl, KBr, and KCL. Which of the following lists in the samples in order of increasing number of moles in the sample?
KBr<KCl<NaCl
A sample of carbonate rock is a mixture of CaCO3 and MgCO3. The rock is analyzed in a laboratory and the results are recorded in the table below. Which columns in the table provided all the information necessary to determine the mole ratio of Ca to Mg in the rock?
Mass of Mg in the sample (g), Mass of Ca in the sample (g), Molar Mass of Mg (g/mol), Molar Mass of Ca (g/mol)
The mass spectrum of a pure element is shown below. Based on the date, the peak at 26 amu represents an isotope of which of the following elements?
Mg with 14 neutrons
According to the information in the table below, a 1.00g sample of which of the following contains the greatest mass of oxygen?
MgO
Which of the following molecules has the shortest bond length?
N2
What are the Bronsted-Lowry bases in the reaction represented below?
NH3(aq) and Cl-(aq)
Which of the following molecules has a pyramidal shape?
NH3(g)
Based on the date in the tables below, which of the following statements provides the best prediction for the boiling point of NaCl?
NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF
Based on the data in the tables below, which of the following statements provides the best prediction for the boiling point of NaCl?
NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in the NaCl than in NaF.
The photoelectron spectra represented below show the energy required to remove a 1s electron from a nitrogen atom and from an oxygen atom. Which of the following statements best accounts for the peak in the upper spectrum being to the right of the peak in the lower spectrum?
Nitrogen atoms have a smaller nuclear charge than oxygen atoms
Of the following single bonds, which is the least polar?
O-F
In the reaction represented below, the number of MnO4- ions that react must be equal to which of the following?
One-fifth the number of Fe^2+ ions that are consumed
In a titration experiment, H2O2(aq) reacts with aqueous MnO4-(aq) as represented by the equations below. The dark purple KMnO4 solution is added from a buret to a colorless, acidified solution of H2O2 (aq) in an Erlenmeyer flask. At the endpoint of the titration, the solution is a pale pink color. Which element is being oxidized during the titration, and what is the element's change in oxidation number?
Oxygen, which changes from -1 to 0
A sample containing atoms of C and F was analyzed using x-ray photoelectron spectroscopy. The portion of the spectrum showing the 1s peaks for atoms of the two elements is shown above. Which of the following correctly identifies the 1s peak for the F atoms and provides an appropriate explanation?
Peak X, because F has a greater nuclear charge than C has
Based on the information represented in the table below and periodic trends, which of the following is the best hypothesis regarding the oxide(s) formed by Rb?
Rb will form Rb2O, Rb2O2, and RbO2
For which of the following molecules are resonance structures necessary to describe the bonding satisfactorily?
SO2
The mass spectrum of element X is presented in the diagram below. Based on the spectrum, which of the following can be concluded about element X?
The atomic mass of X is between 90 and 92
Which of the following can be inferred from the diagram below that shows the dependence of potential energy on the internuclear distance between two atoms?
The atoms form a bond with a bond length of 75 pm
A sample of an ideal gas is cooled from 50.0 C to 25.0 C in a sealed container of constant volume. Which of the following values for the gas will decrease
The average speed of the molecules
Which of the following scientific claims about the bond in the molecular compound HF is most likely to be true?
The bond is highly polar
The elements C and Se have the same electronegativity value, 2.55. Which of the following claims about the compound that forms from C and Se is most likely to be true?
The carbon-selenium bond is nonpolar covalent
The energy required to dissociate an ionic solid into gaseous ions (lattice energy) for the compounds NaF and MgF2 is shown in the table below. On the basis of Coulomb's Law, which of the following best helps to explain the large difference between the lattice energies of NaF and MgF2?
The charge of the Mg cation is larger than that of the Na cation
A 5.0g sample of MgCl2 may contain measurable amounts of other compounds as impurities. Which of the following is (are) needed to determine that the sample is pure MgCl2?
The mass of Mg and the mass pf Cl in the sample
When a sample of oxygen gas in a closed container of constant volume is heated until its absolute temperature is doubled, which of the following is also doubled?
The pressure of the gas
N2 molecules absorb ultraviolet light but not visible light. I2 molecules absorb both visible and ultraviolet light. Which of the following statements explains the observations?
Visible light does not produce transitions between electron energy levels in the N2 molecule but does produce transitions in the I2 molecule.
Based on the ionization energies of element X given in the table below, which of the following is most likely the empirical formula of an oxide of element X?
X2O3
Which of the following diatomic species contains one sigma bond and two pi bonds? a)F2 b) B2 c) N2 d) O2
c) N2
Which of the following diatomic species has a bond order of 2? a)F2 b) B2 c) N2 d) O2
d) O2
The particle-level diagram of a metallic element is shown below. Typically, metals are both malleable and ductile. This best explanation for these properties is that the electrons involved in bonding among metal atoms are...
equally shared and form nondirectional bonds
A student obtains a sample of a pure solid compound. In addition to Avogadro's number, which of the following must the student know in order to determine how many molecules are in the sample?
molar mass of the compound & mass of the sample
The hybridization of the carbon atom in the molecule represented below can be described as??
sp3
For element X represented below, which of the following is the most likely explanation for the large difference between the second and third ionization energies?
the electrons removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were.
How is the geometry of the SO3 molecule best described?
trigonal plannar