AP Chem Midterm
A 0.50 mol sample of He and 0.50 mol of Ne are placed separately in two 10.0 rigid containers at 25 C. Each container has a pinhole opening. Which of the gases, He or Ne, will escape faster through the pinhole and why? A) He will escape faster bc the He atoms are moving at a higher average speed than the Ne atoms. B) Ne will escape faster bc its initial pressure in the container is higher C) Ne will escape faster bc the Ne atoms have a higher average KE than the He atoms. D) Both gases will escape at the same rate bc the atoms of both gases have the same average KE.
A
A mixture containing 0.60 mol Al in contact with 0.75 mol Cl2 is ignited in a closed container according to the rxn below. Assuming complete reaction, which gives the maximum quantity, of AlCl3 produced and the corresponding quantity of unconsumed reactant? 2 Al + 3 Cl2 yields 2 AlCl3 A) 0.50 mol of AlCl3 and 0.10 mol of Al unreacted B) 0.50 mol of AlCl3 and 0.15 mol of Cl2 unreacted C) 0.45 mol of AlCl3 and 0.15 mol of Al unreacted D) 0.45 mol of AlCl3 and 0.15 mol of Cl2 unreacted
A
At 1 mole sample of this gas occupying 1 Liter will have the least density? A) H2 B) O2 C) N2 D) CO2
A
Boiling Point- NaF (1695 C) and MgO (3600 C) Ionic Radium- Na+ (76 pm), Mg2+ (72 pm), F- (133 pm), Cl- (181 pm), O2- (140 pm) Based on the data, which of the following statements provides the best prediction for the boiling point of NaCl? A) NaCl will have a lower boiling point than NaF bc the coulombic attractions are weaker in NaCl than in NaF B) NaCl will have a boiling point in between that of NaF and MgO because the covalent character of the bonds in NaCl is intermediate between that of MgO and NaF C) NaCl will have a higher boiling point than MgO because the ions are spaced farther apart in NaCl D) NaCl will have a higher boiling point than MgO because the energy required to transfer electrons from the anion to the cation is larger in NaCl than in MgO
A
H2 can be produced by adding which of the following to 1 M HCl: I. 1 M NH3 (aq) II. Zn (s) III. NaHCO3 (s) A) II only B) III only C) I and II only D) I, II, and III
A
In the PT, the atomic number increases from 11-17, what happens to the atomic radius? A) decreases only B) remains constant C) increases only D) increases then decreases E) decreases then increases
A
Lattice of positive and negative ions held together by electrostatic forces A) CsCl B) Au C) CO2 D) CH4
A
NH4NO yields N2O + 2 H2O A 0.03 mol sample of NH4NO is placed in 1 L evacuated flask, which is then sealed and heated. The NH4NO decomposes completely according to the balanced equation above. The total pressure in the flask measured at 400 K is closest to which of the following? (use R value- 0.082) A) 3 atm B) 1 atm C) 0.5 atm D) 0.1 atm E) 0.03 atm
A
The size of the H-N-H bond angles of the following species increases in which order? A) NH2- < NH3 < NH4+ B) NH3 < NH2- < NH4+ C) NH3 < NH4+ < NH2- D) NH2- < NH4+ < NH3
A
W + X yields Y + Z Gases W and X react in a closed, rigid vessel to form gases Y and Z according to the equation above. The initial pressure of W is 1.20 atm and that of X is 1.60 atm. No Y or Z is initially present. The experiment is carried out at constant temperature. What is the partial pressure of Z when the partial pressure of W has decreased to 1.00 atm? A) 0.20 atm B) 1.00 atm C) 1.40 atm D) 0.40 atm E) 1.20 atm
A
What element reacts with water to form a strong base? A) Li B) Br C) F D) Ni E) U
A
When 3.0 L of He and 5.0 L of N2 both at 0 C and 1.0 atm, are pumped into an evacuated 4.0 L rigid container, the final pressure in the container at 0 C is A) 2.0 atm B) 4.0 atm C) 6.4 atm D) 16 atm
A
Which atom contains 2 unpaired electrons? A) S B) Ca C) Ga D) Sb E) Br
A
Which has 2 valence electrons in the ground state? A) Magnesium B) Nitrogen C) Sodium D) Fluorine
A
Which is a redox reaction? A) 3 Br2 (aq) + 6 OH- (aq) yields 5 Br- (aq) + BrO3- (aq) + 3 H2O (l) B) S8 (s) + 8 O2 (g) yields 8 SO2 (g) C) Ca2+ (aq) + SO4 2- (aq) yields CaSO4 (s) D) PtCl4 (s) + 2Cl- (aq) yields PtCl6 2- (aq)
A
Which molecule contains pi bonds? A) CO B) CH4 C) HF D) PH3
A
Which of the following compounds is not appreciably soluble in water, but is soluble in diluted HCl? A) Mg(OH)2 B) CuSO4 C) Sr(NO3)2 D) (NH4)2CO3 E) (NH4)2SO4
A
Which of the following gases deviates most from ideal behavior? A) SO2 B) Ne C) CH4 D) N2 E) H2
A
Which of the following has the smallest first ionization energy? A) Lithium B) Carbon C) Nitrogen D) Oxygen E) Fluorine
A
Which of the following represents a process in which a species is oxidized? A) Hg (l) yields Hg2 2+ (aq) B) Fe3+(aq) yields Fe2+(aq) C) NO3- (aq) yields NO2- (aq) D) SO4 2- (aq) yields SO3 2- (aq)
A
2 Al + 6 HCl yields 2 AlCl3 + 3 H2 How many grams of Al (atomic mass= 27 g) are necessary to produce 0.50 mol oh H2 gas at 25 C and 1.00 atm? A) 1.0 g B) 9.0 g C) 14 g D) 27 g E) 56 g
B
At 27 C, 5 identical rigid 2.0 L vessels are filled with N2 and sealed. 4 of the 5 vessels also contain a 0.050 mol sample of NaHCO3, NaBr, Cu, I2 as shown above. The volume taken up by the solids is negligible and the initial pressure of N2 in each vessel is 720 mmHg. All 4 are heated to 127 C and allowed to reach a constant pressure. At 127 C the entire sample of I2 is observed to have vaporized. How does the mass of the vessel 5 at 127 C compare to 27 C? A) The mass is less, since I2 is in the vapor phase B) The mass is the same, since the number of each type of atom in the vessel is constant. C) The mass is greater, since the I2 will react with N2 to from NI3, which has a greater molar mass. D) The mass is greater, since the pressure is greater and the particles have a higher average KE.
B
At constant temperature, the behavior of a sample of a real gas more closely approximates that of an ideal gas as its volume is increased because the A) collisions with the walls of the container become less frequent B)average distance between molecules becomes greater C) molecules have expanded D) average molecular speed decreases E) average molecular KE decreases
B
Closely packed lattice with delocalized electrons throughout A) CsCl B) Au C) CO2 D) CH4
B
Cr2O7 2- + HNO2 + H+ yields Cr 3+ + NO3- + H2O coefficient for H2O when balanced A) 3 B) 4 C) 5 D) 6 E) 8
B
In liquid form this molecules of this gas are paramagnetic according to the Molecular Orbital Theory? A) H2 B) O2 C) N2 D) CO2
B
The half-life of 55 Cr is about 2.0 hrs. The delivery of a pure sample of this isotope from the reactor to a certain laboratory requires 12 hours. About what mass of such material should be skipped in order that 1.0 mg of 55 Cr is delivered to the laboratory? A) 130 mg B) 64 mg C) 32 mg D) 11 mg E) 1.0 mg
B
There is a large jump between IE 3 and IE 4. Which of the following correctly identifies the element in the second period? A) B, because it has 5 core electrons B) B, because it has 3 valence electrons C) N, because it has 5 valence electrons D) N, because it has 3 electrons in the p sublevel
B
What mass of Au is produced when 0.0500 mol of Au2S3 is reduced completely with excess H2? A) 9.85 B) 19.7 C) 24.5 D) 39.4 E) 48.9
B
What minimum value of 0.200 M Na2CO3 is needed to precipitate all the Sr2+ from 25.0 mL of 0.100 M Sr(NO3)2? A) 6.25 mL B) 12.5 mL C) 25 mL D) 50 mL
B
When C10H12O4S + O2 yields CO2 + SO2 + H20 is balanced, what is the coefficient for O2? A) 6 B) 12 C) 28 D) 7 E) 14
B
When hafnium metal is heated in an atmosphere of Cl gas, the product of the rxn is found to contain 62.2% Hf by mass and 37.4% Cl by mass. What is the empirical formula for this compound? A) HfCl B) HfCl3 C) Hf2Cl3 D) HfCl2 E) HfCl4
B
Which group of ions do not usually form precipitates? A) Hg2 2+, Ag+, Pb2+, Ba2+ B) NH4+, K+, Na+, NO3- C) PO4 3-, OH-, S2-, CO3 2- D) SO4 2-, Cl-, Br-, I-
B
Which has a very large 6th ionization energy? A) Magnesium B) Nitrogen C) Sodium D) Fluorine
B
Which is a combination reaction? A) 3 Br2 (aq) + 6 OH- (aq) yields 5 Br- (aq) + BrO3- (aq) + 3 H2O (l) B) S8 (s) + 8 O2 (g) yields 8 SO2 (g) C) Ca2+ (aq) + SO4 2- (aq) yields CaSO4 (s) D) PtCl4 (s) + 2Cl- (aq) yields PtCl6 2- (aq)
B
Which of the following is balanced net ionic equation for the reaction between Li and water? A) 2 Li (s) + 2 H+ (aq) + 2 OH- (aq) yields 2 Li+ (aq) + 2 OH- (aq) + H2 (g) B) 2 Li (s) + 2 H2O (l) yields 2 Li+ (aq) + 2 OH- (aq) + H2 (g) C) 2 Li (s) + 2 H2O (l) yields 2 LiOH (aq) + H2 (g) D) 2 Li (s) + 2 H2O (l) yields 2 LiH (aq) + H2 (g)
B
Which of the following molecules has the largest dipole moment? A) CO2 B) H2O C) CH4 D) C2H4 E) PH3
B
Which of the following molecules is nonpolar but has polar covalent bonds? A) H2O2 B) CF4 C) H2O D) CH2Cl2
B
Which of the following solids is purple in an aqueous solution? A) CuO B) KMnO4 C) KCl D) FeCl3
B
A rigid metal tank contains oxygen gas. Which of the following applies to the gas in the tank when additional oxygen is added at constant temperature? A) The volume of the gas decreases. B) The pressure of the gas decreases. C) The average speed of the gas molecules remains the same. D) The total number of gas molecules remains the same. E) The average distance between the gas molecules increases.
C
All of the following statements about the nitrogen family of elements are true except: A) it contains both nonmetals and metals B) the electronic configuration of the valence shell of the atoms is ns2np3 C) The only oxidation states exhibited by its members of this family are -3, 0, 3, 5 D) The atomic radii increase with increasing atomic number E) The boiling point increases with increasing atomic number
C
At approximately what temperature will have 40 g of argon gas at 1.0 atm occupy a volume of 22.4 L? A) 600 K B) 550 K C) 270 K D) 140 K
C
First IE= 580 kJ/mol Second IE= 1815 kJ/mol Third IE= 2740 kJ/mol Fourth IE= 11600 kJ/mol Fifth IE= 14800 kJ/mol Which of the following elements is most likely represented from this information? A) Na B) Mg C) Al D) P E) Si
C
How many mL of 0.40 M FeBr3 solution would be necessary to precipitate all of the Ag+ form 90 mL of a 0.40 M AgNO3 solution? A) 10 mL B) 20 mL C) 30 mL D) 60 mL
C
If a reaction causes an ion in solution to precipitate in elemental form, this reaction is best described as: A) Decomposition B) Double Displacement C) Redox D) Acid-Base
C
In the ground state, which of the following only has 1 electron in each of the 2p orbitals? A) Lithium B) Carbon C) Nitrogen D) Oxygen E) Fluorine
C
Li3N + H2O yields Li+ + OH- + NH3 When the above equation is balanced and all the coefficients are reduced to the lowest whole-number terms, the coefficient for OH- is: A) 1 B) 2 C) 3 D) 4 E) 6
C
On a mountain top, it is observed that water boils at 90 C, not at 100 C, as at sea level. This phenomenon occurs because on the mountain top the A) Equilibrium water vapor pressure is higher due to the higher atmospheric pressure B) Equilibrium water vapor pressure is lower due to the higher atmospheric pressure C) Equilibrium water vapor pressure equals the atmospheric pressure at a lower temperature D) Water molecules have a higher average KE due to the lower atmospheric pressure E) Water contains a greater conc of dissolved gas
C
Strong multiple covalent bonds (including pi bonds) with weak IMF's A) CsCl B) Au C) CO2 D) CH4
C
The energy required to convert a ground-state atom in the gas phase to a gaseous ion is A) activation energy B) free energy C) ionization energy D) kinetic energy E) lattice energy
C
The hybridization of the C-atoms in the molecule, C2H6, can be represented as: A) sp B) sp2 C) sp3 D) dsp2 E) d2sp
C
The lattice energy of a salt is related to the energy required to separate ions. For which of the following pairs of ions is the energy that is required to separate the ions largest? A) Na+ (g) and Cl- (g) B) Cs+ (g) and Br- (g) C) Mg2+ (g) and O2- (g) D) Ca2+ (g) and O2- (g)
C
Types of hybridization exhibited by the C-atoms in propyne, CH3CCH, including which of the following? I- sp II- sp2 III- sp3 A) I only B) III only C) I and III only D) II and III only
C
What reaction involves neither oxidation or reduction? A) Ignition of iron in powdered sulfur B) Decomposition of potassium chlorate C) Dissolving calcium carbonate in hydrochloric acid D) Catalytic decomposition (Manganese dioxide as a catalyst) of hydrogen peroxide
C
Which atom has only one electron in the highest occupied energy sublevel? A) S B) Ca C) Ga D) Sb E) Br
C
Which equation best represents the ionization behavior of concentrated ammonia in an acid base reaction? A) NH3 yields N3- + 3 H+ B) NH3 yields H+ + NH2- C) NH3 + H2O yields NH4+ + OH- D) NH3 + H2O yields NH2- + H3O+
C
Which has the largest atomic radius? A) Magnesium B) Nitrogen C) Sodium D) Fluorine
C
Which is a double displacement reaction? A) 3 Br2 (aq) + 6 OH- (aq) yields 5 Br- (aq) + BrO3- (aq) + 3 H2O (l) B) S8 (s) + 8 O2 (g) yields 8 SO2 (g) C) Ca2+ (aq) + SO4 2- (aq) yields CaSO4 (s) D) PtCl4 (s) + 2Cl- (aq) yields PtCl6 2- (aq)
C
Which is the most plentiful gas? A) H2 B) O2 C) N2 D) CO2
C
Which molecule has the highest dipole moment? A) CO B) CH4 C) HF D) PH3
C
Which of the following best explains why the normal boiling point of CCl4 (350 K) is higher than the normal boiling point of CF4 (145 K)? A) the C-Cl bonds in CCl4 are less polar than the C-F bonds in CF4 B) The C-Cl bonds in CCl4 are weaker than the C-F bonds in CF4 C) The electron cloud of the CCl4 molecule is more polarizable than that of CF4 molecule D) The mass of the CCl4 molecule is greater than that of the CF4 molecule
C
Which of the following equations represents the net reaction that occurs when gaseous HF acid with solid SiO2 A) 2 H+ + 2 F- + SiO2 yields SiOF2 + H20 B)4 F- + SiO2 yields SiF4 + O2 2- C) 4 HF + SiO2 yields SiF4 + 2 H20 D) 4 HF + SiO2 yields Si + 2 F2 + 2 H2O E) 2 H2F + Si2O2 yields 2 SiF + 2 H2O
C
Which of the following is a gas in its standard state? A) Li B) Br C) F D) Ni E) U
C
Which of the following is true of all alkali metals? A) they have oxides that act as acid anhydrides B) They form covalent bonds with oxygen C) They are generally found in nature only in compounds D) They have relatively large first IE
C
Which of the solids is very white and soluble in water? A) CuO B) KMnO4 C) KCl D) FeCl3
C
235 U + 1 n yields 141 Cs + 3 1 n + X 92 0 55 0 Neutron bombardment of uranium can induce the reaction represented above. Nuclide X is which of the following. A) 92 Br B) 94 Br C) 91 Rb D) 92 Rb E) 94 Rb 35 35 37 37 37
D
A certain crystalline substance that has a low melting point does not conduct electricity in solution or when melted. This substance is likely to be: A) network solid B) metallic solid C) ionic solid D) molecular solid
D
A sealed vessel contains 0.200 mol of O2 gas, 0.100 mol of N2 gas, and 0.200 mol of Ar gas. The total pressure 5.00 atm. What is the partial pressure of the Ar gas? A) .200 atm B) .500 atm C) 1.00 atm D) 2.00 atm E) 5.00 atm
D
According to the VSEPR model, the progressive decrease in the bond angles in the series of molecules CH4, NH3, H2O is best accounted for by the A) increasing strength of bonds B) decreasing size of central atom C) increasing electronegativity on central atom D) increasing number of unshared pairs of electrons E) decreasing repulsion between H atoms
D
At a given temperature, this gas will have the lowest rate of effusion? A) H2 B) O2 C) N2 D) CO2
D
Equal numbers of moles of He, Ar, and Ne are placed in a glass vessel at room temperature. If the vessel has a pinhole - sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused? A) P He < P Ar < P Ne B) P Ne < P Ar < P He C) P Ar < P He < P Ne D) P He < P Ne < P Ar E) P He = P Ar < P Ne
D
If 87.5% of a sample of pure 131 I decays in 24 days, what is the half life of 131 I? A) 21 days B) 14 days C) 12 days D) 8 days E) 6 days
D
In which of the following processes are the covalent bonds broken? A) I2 (s) yields I2 (g) B) CO2 (s) yields CO2 (g) C) NaCl (s) yields NaCl (l) D) C (diamond) yields C (gas) E) Fe (s) yields Fe (l)
D
M+ is an unknown metal cation with a 1+ charge. A student dissolves "M" in enough water to make 100.0 mL of solution. The student then mixes the solution with excess AgNO3 solution, causing AgCl to precipitate. The student collects the precipitate by filtration, dries it, and records the following data: The molar mass of AgCl is (143 g/mol). Mass of unknown chloride, MCl (0.74 g) Mass of Filter Paper (0.80 g) Mass of Filter Paper plus AgCl precipitate (2.23 g) What is the identity of the metal chloride? A) NaCl B) LiCl C) CuCl D) KCl
D
Strong single covalent bonds with weak IMF's A) CsCl B) Au C) CO2 D) CH4
D
The molecules of this nonpolar gas contain polar bonds. A) H2 B) O2 C) N2 D) CO2
D
The safest and most effective emergency procedure to treat an acid splash on skin is to do which of the following immediately? A) Dry the affected area with paper towels B) Sprinkle the affected area with Na2SO4 C) Flush the affected area with water and then dilute NaOH solution D) Flush the affected area with water then with NaHCO3 solution E) Flush the affected area with water then with dilute vinegar solution
D
When NaCl is vaporized in a flame, what color is the flame? A) blue B) green C) white D) yellow E) violet
D
Which gas will deviate most? A) Ne B) Ar C) Kr D) Xe
D
Which has the largest dipole moment? A) CO B) CO2 C) O2 D) HF E) F2
D
Which molecule has trigonal pyramidal geometry? A) CO B) CH4 C) HF D) PH3
D
Which of the following molecules only has one double bond? A) CO2 B) H2O C) CH4 D) C2H4 E) PH3
D
Which of the following represents a process in which a species is reduced? A) Ca (s) yields Ca2+ (aq) B) Hg (l) yields Hg2 2+ (aq) C) Fe 2+ (aq) yields Fe3+ (aq) D) NO3- (aq) yields NO (g) E) SO3 2- (aq) yields SO4 2-
D
Which reaction produces a coordination complex? A) 3 Br2 (aq) + 6 OH- (aq) yields 5 Br- (aq) + BrO3- (aq) + 3 H2O (l) B) S8 (s) + 8 O2 (g) yields 8 SO2 (g) C) Ca2+ (aq) + SO4 2- (aq) yields CaSO4 (s) D) PtCl4 (s) + 2Cl- (aq) yields PtCl6 2- (aq)
D
Which types of hybridization are exhibited by the C-atoms in propene, CH3CHCH2? I= sp II= sp2 III= sp3 A) I only B) III only C) I and II only D) II and III only E) I, II, III
D
A hot air balloon rises. Which of the following is the best explanation for this observation? A) The pressure on the walls of the balloon increases with increasing temperature. B) The difference in temperature between the air inside and outside the balloon produces convection currents. C) The cooler air outside the balloon pushes in on the walls of the balloon. D) The rate of diffusion of cooler air is less than that of warmer air. E) The air density inside the balloon is less than that of the surrounding air.
E
HI + KMnO4 + H2SO4 yields I2 + MnSO4 + K2SO4 + H2O According to the above equation (needs to be balanced), how many moles of HI would be necessary to produce 2.5 moles of I2, starting with 4.0 moles of KMnO4 and 3.0 moles of H2SO4? A) 20 B) 8 C) 2.5 D) 10 E) 5
E
Nonane- Molecular Formula (C9H20), Molar Mass (128), Boiling Point (151) 2,3,4-trifluoropentane- Molecular Formula (C9H5F3), Molar Mass (126), Boiling Point (89) Both molecules have almost identical molar masses, but nonane has a significantly higher boiling point. Which of the following statements best explains this? A) The C-F bond is easier to break than the C-H bond. B) The C-F bond is more polar than the C-H bond C) The carbon chains are farther apart in a sample of nonane they are in 2,3,4-trifluoropentane. D) The carbon chains are more complex in nonane than they are in 2,3,4-trifluoropentane.
E
What formula unit would be expected for the binary compound of Al and P? A) Al3P3 B) AlP3 C) Al3P D) Al2P3 E) AlP
E
Which molecule has a trigonal pyramidal geometry? A) CO2 B) H2O C) CH4 D) C2H4 E) PH3
E
Which of the following has the smallest atomic radius? A) Lithium B) Carbon C) Nitrogen D) Oxygen E) Fluorine
E
Which of the following is a correct interpretation for the results of Rutherford's gold foil experiment in which atoms were bombarded with alpha particles? A) Atoms have equal numbers of positive and negative charges B) Neutrons are at the center of an atom C) Electrons in atoms are arranged in shells D) Neutrons and protons in atoms have nearly equal mass E) The positive charge of an atom is concentrated in a small region
E
Which of the following molecules is not planar? A) CO3 2- B) NO3- C) ClF3 D) BF3 E) PCl3
E
