AP Chemistry Midterm
How many grams of glucose (F.W. = 180.156) are present in 500. mL of a 0.50 M glucose solution?
45g
Which of the following represents the net-ionic equation for the reaction that occurs when solutions of acetic acid and potassium hydroxide are mixed?
CH3COOH(aq) + OH-(aq) goes to H2O(l) CH3COO-(aq)
I2(g) + 3Cl2(g) goes to 2ICl3(g) delta H=? I-I 150 Cl-Cl 240 I-Cl 210 A. -390 kJ B. 180 kJ C. +180 kJ D. +390 kJ
A. -390 kJ
Three different Lewis structures for the cyanate ion (NCO-) are shown above. Which structure, if any, is the most favorable (or dominant)? A. #1, because the C-N bond length is nearly equal to the C-O bond length. B. #2, because the most electronegative atom carries the negative formal charge C. #3, because the most electronegative atom is part of a strong triple bond D. All three Lewis structures for the cyanate ion are equally favorable
B. #2, because the most electronegative atom carries the negative formal charge
N2(g) + 3H2(g) goes to 2NH3(g) delta H=-92.4 KJ The synthesis of ammonia is illustrated by the thermochemical equation shown above. Which of the following calculations is set up correctly to determine the mass of ammonia produced when 875 J of heat is released in this reaction? A. (875)(92.4)(17.034)/(1000)(2) B. (875)(2)(17.034)/(1000)(92.4) C. (875)(1000)(92.4)(17.034)/(2) D. (875)(1000)(2)(17.034)/(92.4)
B. (875)(2)(17.034)/(1000)(92.4)
Which of the following represents the ground state electron configuration and an excited state electron configuration for the same element? A. ground state: 1s2 2s2 2p1 excited state: 1s2 2s2 2d1 B. ground state: 1s2 2s2 2p6 excited state: 1s2 2s2 2p5 3s1 C. ground state: 1s2 2s2 2p5 excited state: 1s2 2s2 2p6 D. ground state: 1s2 2s2 2p6 3s2 excited state: 1s2 2s2 2p5 3s3
B. ground state: 1s2 2s2 2p6 excited state: 1s2 2s2 2p5 3s1
Which of the following properties tends to decrease as you move from top to bottom down Group 14? A. atomic radius B. ionization energy C. metallic character D. reactivity with oxygen
B. ionization energy
In a certain experiment, 200 J of work is done by the surroundings on the system as a gas is compressed. In addition, 500 J of heat is transferred from the system to the surroundings. Which of the following has correctly identified the signs of q, w, and delta E for the system? A. q- w+ delta E+ B. q- w+ delta E- C. q+ w- delta E+ D. q+ w- delta E-
B. q- w+ delta E-
There are eight elements located in Period 3 of the periodic table. How many of these elements have a ground state electron configuration that contains exactly two unpaired electrons? A. one B. two C. three D. four
B. two
Which of the following bonds has the largest dipole moment? A. C-N B. P-S C. As-F D. Se-Br`
C. As-F
Two types of electromagnetic radiation, X and Y, are represented in the data table above. Which of the following are the most probable values for wavelength and energy associated with Y? A. 1 x 10-20m, 2 x 10-5 J B. 1 x 10-20m, 2 x 10-19 J C. 1 x 10-6m, 2x 10-5 J D. 1 x 10-6m, 2 x 10-19 J
D. 1 x 10-6m, 2 x 10-19 J
H2(g) + 1/2O2(g) goes to H2O(l) delta H=A 2Na(s) + 1/2O2(g) goes to Na2O(s) delta H=B Na(s) + 1/2O2(g) + 1/2H2(g) goes to NaOH(s) delta H=C Based on the information above, what is the standard enthalpy change for the following reaction? Na2O(s) + H2O(l) goes to 2NaOH(s) delta H=? A. A + B - C B. A + B - 2C C. C - A - B D. 2C - A - B
D. 2C - A - B
Which of the following molecules has a Lewis structure that is identical to nitrogen triiodide? A. Sulfur trioxide B. Boron trichloride C. Chlorine trifluoride D. Arsenic tribromide
D. Arsenic tribromide
Which of the following processes would release the largest quantity of energy? A. KBr(s) goes to K+(g) + Br-(g) B. MgO(s) goes to Mg 2+(g) + O 2-(g) C. K+(g) + Br-(g) goes to KBr(s) D. Mg 2+(g) + O 2-(g) goes to MgO(s)
D. Mg 2+(g) + O 2-(g) goes to MgO(s)
Which of the following lists is arranged in order of increasing bond angle (smallest to largest) A. NF3, CF4, BF3 B. NF3, BF3, CF4 C. CF4, NF3, BF3 D. CF4, BF3, NF3
NF3, CF4, BF3
Which of the following solutes does the diagram best represent?
calcium chloride
Which of the following would result in the formation of a precipitate when aqueous solutions of each substance are mixed together?
sodium iodide and lead(II) nitrate
Which of the following calculations is set up correctly to determine the mass percentage of iodide in the KI tablet?
(0.200)(2)(126.9)/(461.0)(0.500) x 100
Under which of the following situations will the sign of delta E always be positive? A. heat is absorbed by the system and work is done on the system B. heat is absorbed by the system and work is done on the surroundings C. heat is released by the system and work is done on the system D. heat is released by the system and work is done on the surroundings
A. heat is absorbed by the system and work is done on the system.
The figure above represents three sealed 1.0 L vessels, each containing a different inert gas at 298 K. The pressure of Ar in the first vessel is 2.0 atm. The ratio of numbers of Ar, Ne, and He atoms in the vessels is 2:1:6, respectively. After all the gases are combined in a previously evacuated 2.0 L vessel, what is the total pressure of the gases at 298 K? A. 3.0 atm B. 4.5 atm C. 9.0 atm D. 1.8 atm
B. 4.5 atm
Based on the information in the table above, what is the most likely identity of this element? A. Mg B. Al C. Si D. P
B. Al
The first ionization energy of an element required to remove an electron from a gaseous atom of the element (X(g) goes to X+(g) + e-). The values of the first ionization energies for the third-row elements are shown in the graph above. On the basis of the information given, which of the following reactions is exothermic? A. Cl(g) + Mg+(g) goes to Cl+(g) + Mg(g) B. Al(g) + Mg+(g) goes to Al+(g) + Mg(g) C. P(g) + Mg+(g) goes to P+(g) + Mg(g) D. S(g) + Mg+(g) goes to S+(g) + Mg(g)
B. Al(g) + Mg+(g) goes to Al+(g) + Mg(g)
The first five ionization energies of a second-period element are listed in the table above. Which of the following correctly identifies the element and best explains the data in the table? 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. B, because it has 3 valence electrons
Based on the trends in chemical reactivity for the alkali metals and the halogens, which of the following reactions should NOT occur? A. I2 + 2KCl goes to 2KI + Cl2 B. F2 + 2NaBr goes to 2NaF + Br2 C. 2K + 2H2O goes to 2KOH + H2 D. Na + H2 goes to 2NaH
B. F2 + 2NaBr goes to 2NaF + Br2
Which of the following choices represents the correct estimates of the bond angles in methane and water? A. H-C-H in CH4: 90 H-O-H in H20: 180 B. H-C-H in CH4: 109.5 H-O-H in H2O: 105 C. H-C-H in CH4: 109.5 H-O-H in H2O: 109.5 D. H-C-H in CH4: 109.5 H-O-H in H2O: 115
B. H-C-H in CH4: 109.5 H-O-H in H2O: 105
Mg 2+(aq) + SO4 2-(aq) goes to MgSO4(s) delta H=+96KJ Use the information given in the thermochemical equation shown above to help you choose the best answer to the following question. What will happen when solid MgSO4 is dissolved completely in water at 25 degrees Celsius? A. Heat will be absorbed by the system and the temperature of the water will increase. B. Heat will be released by the system and the temperature of the water will increase C. Heat will be absorbed by the system and the temperature of the water will decrease D. Heat will be released by the system and the temperature of the water will decrease
B. Heat will be released by the system and the temperature of the water will increase
A pure sample of XCl3 exists as a colorless liquid and has a boiling point of 76 degrees Celsius. Which of the following choices represents a possible identity of element X and the type of bonding present in XCl3? A. Identity: Phosphorus bonding: Ionic B. Identity: Phosphorus bonding: Covalent C. Identity: Nickel bonding: Ionic D. Identity: Nickel bonding: Covalent
B. Identity: Phosphorus bonding: Covalent
Which of the following statements most accurately describes boron trifluoride? A. It is a nonpolar substance that contains nonpolar bonds B. It is a nonpolar substance that contains polar bonds C. It is a polar substance that contains nonpolar bonds D. It is a polar substance that contains polar bonds
B. It is a nonpolar substance that contains polar bonds
Which of the following could be the identity of a while crystalline solid that exhibits the following properties? It melts at 320 degrees Celsius It does not conduct electricity as a solid It conducts electricity in aqueous solution A. C6H12O6(s) B. NaOH(s) C. SiO2(s) D. Cu(s)
B. NaOH(s)
Which of the following has a bent molecular geometry with a bond angle of approximately 120 degrees? A. H2O B. O3 C. BF3 D. CH4
B. O3
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? A. Peak X, because F has a smaller first ionization energy than C has. B. Peak X, because F has a greater nuclear charge than C has C. Peak Y, because F is more electronegative than C is. D. Peak Y, because F has a smaller atomic radius than C has.
B. Peak X, because F has a greater nuclear charge than C has
The contents of the closed box in each of the diagrams above represent a system, and the arrows show the changes of the system during some process. The lengths of the arrows represent the relative magnitudes of q and w. Which of the following statements is true? A. Process 1 represents an endothermic process B. Process 2 represents an endothermic process C. In Process 3, delta E < 0. D. In Process 4, work is being done by the surroundings on the system.
B. Process 2 represents an endothermic process.
On the basis of the information above, which of the following arranges the binary compounds in order o increasing bond polarity? A. CH4 < SiCl4 < SF4 B. CH4 < SF4 < SiCl4 C. SF4 < CH4 < SiCl4 D. SiCl4 < SF4 < CH4
A. CH4 < SiCl4 < SF4
Which of the following has the bonds arranged in order of decreasing polarity? A. H-F > N-F > F-F B. H-I > H-Br > H-F C. O-N > O-S > O-Te D. Sb-I > Sb-Te > Sb-Cl
A. H-F > N-F > F-F
Which of the following series is listed in order of increasing radius? A. K+ K Rb B. Ca 2+ Ca Mg C. O 2- O S D. P 3- P N
A. K+ K Rb
Which of the following statements is most closely associated with the photoelectric effect? A. Light shining on a clean metal surface causes the surface to emit electrons B. Energy is emitted by the electrons as they travel from an higher energy state toward a lower energy state. C. Electrons exist only in certain discrete energy levels, which are described by quantum numbers. D. The solutions to Schrodinger's equation for the hydrogen atom yields a set of wave functions called orbitals.
A. Light shining on a clean metal surface causes the surface to emit electrons
2Na2O2(s) + S(s) + H2O(l) goes to 4NaOH(aq) + SO2(aq) delta H=-600 KJ/mol In a certain experiment, 7.8 g Na2O2(s) is mixed with 3.2 g S(s) along with excess water. Which of the following identifies the limiting reactant and the heat released, q, for this experiment? A. Limiting reactant: Na2O2 q: 30 KJ B. Limiting reactant: Na2O2 q: 60 KJ C. Limiting reactant: S q: 30 KJ D. Limiting reactant: S q: 60 KJ
A. Limiting reactant: Na2O2 q: 30 KJ
Based on this information, which of the following substances is most likely to represent the identity of Compound X?
Barium Chloride
On the basis of molecular structure and bond polarity, which of the following compounds is most likely to have the greatest solubility in water? A. CH4 B. CCl4 C.NH3 D. PH3
C. NH3
CH4(g) + Cl(g) goes to CH3(g) + HCl(g) delta H=-14 kJ/mol NH3(g) + Cl(g) goes to NH2(g) + HCl(g) delta H=-36 kJ/mol H2O(g) + Cl(g) goes to OH(g) + HCl(g) delta H=+40 kJ/mol Based on the data above, what can be concluded regarding the strength of the C-H, N-H, and O-H bonds in the molecules shown? A. The C-H bond is the strongest. B. The N-H bond is the strongest C. The O-H bond is the strongest D. Nothing can be concluded without knowing the strength of the H-Cl bond
C. The O-H bond is the strongest
The volume of a sample of air in a cylinder with a movable piston is 2.0 L at a pressure P1, as shown in the diagram above. The volume is increased to 5.0 L as the temperature is held constant. The pressure of the air in the cylinder is now P2. What effect do the volume and pressure changes have on the average kinetic energy of the molecules in the sample? A. The average kinetic energy increases B. The average kinetic energy decreases C. The average kinetic energy stays the same D. It cannot be determined how the kinetic energy is affected without knowing P1 and P2
C. The average kinetic energy stays the same
X(g) goes to X+(g) + e- IE=740 kJ/mol X+(g) goes to X 2+(g) + e- IE=1450 kJ/mol X 2+(g) goes to X 3+(g) + e- IE=7730 kJ/mol For the element X represented above, which of the following is the most likely explanation for the large difference between the second third ionization energies? A. The effective nuclear charge decreases with successive ionizations B. The shielding of outer electrons increases with successive ionizations C. The electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were D. The ionic radius increases with successive ionizations
C. The electron removed during the third ionization is, on average, much closer to the nucleus than the first two electrons removed were
The diagram above represents the photoelectron spectrum for beryllium. Which of the following statements is correct Peak A and Peak B? A. The electrons represented by Peak A require more energy to remove because they are located in a full s orbital. B. The electrons represented by Peak B require more energy to remove because they are located in a full s orbital. C. The electrons represented by Peak A require more energy to remove because they are closer to he nucleus. D. The electrons represented by Peak B require more energy to remove because they are closer to the nucleus.
C. The electrons represented by Peak A require more energy to remove because they are closer to he nucleus.
CO(g) + 2H2(g) goes to CH3OH(g) delta H < 0 The sythesis of CH3OH(g) from CO(g) and H2(g) is represented by the equation above. The value of K for the reaction at 483 K is 145. Which of the following statements is true about bond energies in this reaction? A. The energy absorbed as the bonds in the reactants are broken is greater than the energy released as the bonds in the product are formed B. The energy released as the bond in the reactants are broken is greater than the energy absorbed in the product formed. C. The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed D. The energy released as the bonds in the reactants are broken is less than the energy absorbed as the bonds in the products are formed.
C. The energy absorbed as the bonds in the reactants are broken is less than the energy released as the bonds in the product are formed
The table above shows the first ionization energy and atomic radius of several elements. Which of the following best helps to explain the deviation of the first ionization of oxygen from the overall trend? A. The atomic radius of oxygen is greater than the atomic radius of fluorine B. The atomic radius of oxygen is less than the atomic radius of nitrogen C. There is repulsion between paired electrons in oxygen's 2p orbitals D. There is attraction between paired electrons in oxygen's 2p orbitals
C. There is repulsion between paired electrons in oxygen's 2p orbitals
Based on the ionization energies of element X given in the table above, which of the following is most likely the empirical formula of an oxide element X? A. XO2 B. X2O C. X2O3 D. X2O5
C. X2O5
The ionization energies of an unknown element, X, are listed in the table above. Which of the following is the most likely empirical formula of a compound formed from element X and phosphorus, P? A. XP B. X3P C. X3P2 D. X3P4
C. X3P2
A 1.0 L sample of a pure gas is found to have a lower pressure than predicted by the ideal gas law. The best explanation for the observation is that the molecules of the gas. A. have a combined volume that is too large to be considered negligible when compared to the volume of the container B. have a low molecular mass and therefore do not strike the container walls with as much force as expected C. are attracted to each other and do not exert as much force on the container walls as they would if they had no mutual attractions D. are attracted to the sides of the container and strike the container walls with more force than expected
C. are attracted to each other and do not exert as much force on the container walls as they would if they had no mutual attractions
Zn(s) is used to reduce other compounds in chemical reactions. If a chemist needs a substance that is more effective in its reducing ability, which of the following species would be the best choice? A. Na B. H+ C. K+ D. Cl-
A. Na
Based on the data in the tables above, 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 because the coulombic attractions are weaker in NaCl than in NaF. B. NaCl will have a boiling point 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. NaCl will have a lower boiling point than NaF because the coulombic attractions are weaker in NaCl than in NaF.
Which of the following series is listed in order of increasing O-O bond length (from shortest O-O bond to longest O-O bond)? A. O2, O3, H2O2 B. O2, H2O2, O3 C. O3, O2, H2O2 D. O3, H2O2, O2
A. O2, O3, H2O2
The potential energy of a system of two atoms as a function of their internuclear distannce is shown in the diagram above. Which of the following is true regarding the forces between the atoms when their internuclear distance is x? A. The attractive and repulsive forces are balanced, so the atoms will maintain an average internuclear distance x. B. There is a net repulsive force pushing the atoms apart, so the atoms will move farther apart C. There is a net attractive pulling the atoms together, so the atoms will move closer together D. It cannot be determined whether the forces between atoms are balanced, attractive, or repulsive, because the diagram shows only the potential energy
A. The attractive and repulsive forces are balanced, so the atoms will maintain an average internuclear distance x.
CH3OH(g) goes to CO(g) + 2H2(g) delta H=+91 kJ/mol The reaction represented above goes essentially to completion. The reaction takes place in a rigrid, insulated vessel that is initially at 600 K. Which of the following statements about the bonds in the reactants and products is most accurate? A. The sum of the bond enthalpies of the bonds in the reactant is greater than the sum of the bond enthalpies of the bonds in the products. B. The sum of the bond enthalpies of the bonds in the reactant is less than the sum of the bond enthalpies of the bonds in the products. C. The length of the bond between carbon and oxygen in CH3OH is shorter than the length of the bond between carbon and oxygen in CO. D. All of the bonds in the reactant and products are polar.
A. The sum of the bond enthalpies of the bonds in the reactant is greater than the sum of the bond enthalpies of the bonds in the products.
A balloon filled with 0.25 mol of He(g) at 273 K and 1 atm is allowed to rise through the atmosphere. Which of the following explains what happens to the volume of the balloon as it rises from ground level to an altitude where the air temperature is 220 K and the air pressure is 0.1 atm? A. The volume will increase because the decrease in air pressure will have a greater effect than the decrease in temperature B. The volume will remain unchanged because of the counteracting effects of the decrease in temperature and the decrease in air pressure C. The volume will decrease because the decrease in temperature will have a great effect than the decrease in air pressure D. It cannot be determined whether the volume of the balloon will increase, decrease, or remain the same without knowing the initial volume of the balloon
A. The volume will increase because the decrease in air pressure will have a greater effect than the decrease in temperature
delta Hf for CO2(g) = X kJ/mol and delta Hf for H2O(l) = Y kJ/mol The value of delta H for the combustion of methane gas is equal to -890 kJ as shown above. The standard enthalpy of formation for CO2(g) is equal to X kilojoules per mole. The standard enthalpy of formation for H2O(l) is equal to Y kilojoules per mole. In terms of X and Y, the standard enthalpy of formation for methane gas is equal to A. X + 2Y + 890 B. X + 2Y - 890 C. X + Y + 890 D. X + Y - 890
A. X + 2Y + 890
The potential energy as a function of internuclear distance for three diatomic molecules, X2, Y2, and Z2, is shown in the graph above. Based on the data in the graph, which of the following correctly identifies the diatomic molecules, X2, Y2, and Z2? A. X2: H2 Y2: N2 Z2: O2 B. X2: H2 Y2: O2 Z2: N2 C. X2: N2 Y2: O2 Z2: H2 D. X2: O2 Y2: H2 Z2: N2
A. X2: H2 Y2: N2 Z2: O2
C2H2(g) + Cl2(g) goes to C2H2Cl2(g) When Reaction 3 occurs, does the hybridization of the carbon atoms change? A. Yes; it changes from sp to sp2 B. Yes; it changes from sp to sp3 C. Yes; it changes from sp2 to sp3 D. No; it does not change
A. Yes; it changes from sp to sp2
When electrons are removed from an atom to form a cation, they are always removed first from the occupied orbitals having the largest principal quantum number (n). Which of the following represents the ground state electron configuration for the Co 2+ ion? A. [Ar] 3d7 B. [Ar] 3d5 4s2 C. [Ar] 3d6 4s1 D. [Ar] 3d7 4s1
A. [Ar] 3d7
Which of the following is the reason that ionization energy generally increases from left to right across the first period of the periodic table? A. As the atomic number increases, the electrons are harder to remove B. Ionization energy increases as the atomic number increases C. As the atomic number increases, more electrons are added to the atoms, thus increasing electron-electron repulsion D. As the atomic number increases, more protons in the nucleus cause an increase in the effective nuclear charge, making it harder to remove the electrons
D. As the atomic number increases, more protons in the nucleus cause an increase in the effective nuclear charge, making it harder to remove the electrons
A vessel contains Ar(g) at a high pressure. Which of the following statements best helps to explain why the measured pressure is significantly greater than the pressure calculated using the ideal gas law? A. the molar mass of Ar is relatively large B. a significant number of Ar2 molecules form C. the attractive forces among Ar atoms cause them to collide with the walls of the container with less force D. The combined volume of the Ar atoms is too large to be negligible compared with the total volume of the container
D. The combined volume of the Ar atoms is too large to be negligible compared with the total volume of the container
The BF3 molecule is nonpolar, whereas the NF3 molecule is polar. Which of the following statements accounts for the difference in polarity of the two molecules? A. In NH3, each F is joined to N with multiple bonds, whereas in BF3, each F is joined to B with single bonds B. N-F bonds are polar, whereas B-F bonds are nonpolar C. NF3 is an ionic compound, whereas BF3 is a molecular compound D. Unlike BF3, NF3 has nonpolar geometry due to an unshared pair of electrons on the N atom.
D. Unlike BF3, NF3 has nonpolar geometry due to an unshared pair of electrons on the N atom.
Lewis electron-dot diagrams for CO2 and SO2 are given above. The molecular geometry and polarity of the two substances are A. the same because the molecular formulas are similar B. the same because C and S have similar electronegativity values C. different because the lone pair of electrons on the S atom make it the negative end of a dipole D. different because S has a greater number of electron domains (regions of electron density) surrounding it than C has
D. different because S has a greater number of electron domains (regions of electron density) surrounding it than C has
The hybridization of the carbon atoms in acetone, (CH3)2CO, is best described as A. sp2 for all three carbon atoms B. sp3 for all three carbon atoms C. either sp or sp2 D. either sp2 or sp3
D. either sp2 or sp3
Which diagram best represents the shape of BrF5? A. square planar B. octahedral C. trigonal bipyramidal D. square pyramidal
D. square pyramidal
The ideal gas law best describes the properties of which of the following gases at 0 degrees Celsius and 1 atm? A. PH3 B. HBr C. SO2 D. N2
D. N2
The photonelectron sprecta above 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? A. Nitrogen atoms have a half-filled p subshell. B. There are more electron-electron repulsions in oxygen atoms than in nitrogen atoms. C. Electrons in the p subshell of oxygen atoms provide more shielding than electrons in the p subshell of nitrogen atoms. D. Nitrogen atoms have a smaller nuclear charge than oxygen atoms.
D. Nitrogen atoms have a smaller nuclear charge than oxygen atoms.
Based on the information above and periodic trends, which of the following is the best hypothesis regarding the oxide(s) formed by Rb? A. Rb will form only Rb2O B. Rb will form only RbO2 C. Rb will form only Rb2O and Rb2O2 D. Rb will form Rb2O, Rb2O2, and RbO2
D. Rb will form Rb2O, Rb2O2, and RbO2
Based on periodic trends and the data in the table above, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively? A. 242 pm, 633 kJ/mol B. 242 pm, 419 kJ/mol C. 120 om, 633 kJ/mol D. 120 pm, 419 kJ/mol
B. 242 pm, 419 kJ/mol
A 100 g sample of a metal was heated to 100 degrees Celsius and then quickly transferred to an insulated container holding 100 g of water at 22 degrees Celsius. The final temperature of the water (and the metal) was equal to 35 degrees Celsius. Which of the following can be concluded? A. The metal temperature changed more than the water temperature did; therefore the amount of heat lost by the metal is greater than the amount of heat gained by the water. B. The metal temperature changed more than the water temperature did, but the amount of heat lost by the metal is equal to the amount of heat gained by the water. C. The metal temperature changed more than the water temperature did; therefore the specific heat of the metal is greater than the specific heat of the water D. The metal temperature changed more than the water temperature did, but the specific heat of the metal is equal to the specific heat of the water
B. The metal temperature changed more than the water temperature did, but the amount of heat lost by the metal is equal to the amount of heat gained by the water.
Based on periodic trends and the data in the table above, which of the following are the most probable values of the atomic radius and the first ionization energy for potassium, respectively? A. 144 pm, 419 kJ/mol B. 144 pm, 633 kJ/mol C. 196 om, 419 kJ/mol D. 196 pm, 633 kJ/mol
C. 196 pm, 419 kJ/mol
When 4.0 L of He(g), 6.0 L of N2(g), and 10. L of Ar(g), all at 0 degrees Celsius and 1.0 atm, are pumped into an evacuated 8.0 L rigid container, the final pressure in the container at 0 degrees Celcius is A. 0.5 atm B. 1.0 atm C. 2.5 atm D. 4.0 atm
C. 2.5 atm
In an insulated cup of negligible heat capacity, 50. g of water at 40. degrees Celsius is mixed with 30. g of water at 20. degrees Celsius. The final temperature of the mixture is closest to A. 27 degrees Celsius B. 30 degrees Celsius C. 33 degrees Celsius D. 38 degrees Celsius
C. 33 degrees Celsius
A certain substance is dissolved in water, forming a basic (pH > 7) solution. With respect to the possible identity of the substance and its reaction with water, which of the following choices is most likely to be correct? A. Identity: CO2 Reaction: CO2 + H2O goes to H2CO3 B. Identity: SO2 Reaction: SO2 + H2O goes to HSO2+ + OH- C. Identity: CaO Reaction: CaO + H2O goes to Ca(OH)2 D. Identity: BaO Reaction: BaO + H2O goes to Ba + H2O2
C. Identity: CaO Reaction: CaO + H2O goes to Ca(OH)2
Under which of the following conditions of temperature and pressure will H2 gas be expected to behave most like an ideal gas? A. 50 K and 0.10 atm B. 50 K and 5.0 atm C. 500K and 0.10 atm D. 500 K and 50 atm
C. 500K and 0.10 atm
Which of the following correctly identifies which has the higher first-ionization energy, Cl or Ar, and supplies the best justification? A. Cl, because of its higher electronegativity B. Cl, because of its higher electron affinity C. Ar, because of its completely filled valence shell D. Ar, because of its higher effective nuclear charge
C. Ar, because of its completely filled valence shell
Which of the following molecules contains exactly three sigma bonds and two pi bonds? A. HCN B. HCO2H C. C2H2 D. C2H4
C. C2H2
The compound CCl4 is nonflammable and was once commonly used in fire extinguishers. On the basis of the periodic properties, which of the following compounds can most likely be used as a fire-resistant chemical? A. BCl3 B. CH4 C. CBr4 D. PbCl2
C. CBr4
The complete photoelectron spectra of neutral atoms of two unknown elements, X and Y, are shown above. Which of the following can be inferred from the data? A. Element X has a greater electronegativity than element Y does. B. Element X has a greater ionization energy than element Y does. C. Element Y has a greater nuclear charge than element X does. D.The isotopes of element Y are approximately equal in abundance, but those of element X are not.
C. Element Y has a greater nuclear charge than element X does.
Which of the following choices most accurately describes both the molecular geometry and the polarity for both CO2 and SO2? A. CO2: linear and polar; SO2: bent and nonpolar B. CO2: linear and nonpolar; SO2: linear and polar C. CO2: linear and nonpolar; SO2: linear and nonpolar D. CO2: linear and nonpolar; SO2: bent and polar
D. CO2: linear and nonpolar; SO2: bent and polar
The photoelectron spectra of the 1s electrons of two isoelectronic species, Ca 2+ and Ar, are shown above. Which of the following correctly identifies the species associated with peak X and provides a valid justification? A. Ar, because it has completely filled energy levels B. Ar, because its radius is smaller than the radius of Ca 2+ C. Ca 2+, because its nuclear mass is greater than that of Ar. D. Ca 2+, because its nucleus has two more protons than the nucleus of Ar has
D. Ca 2+, because its nucleus has two more protons than the nucleus of Ar has