Data Interpretation - 5 STEPS TO A 5: 500 AP Chemistry Questions to Know by Test Day! (2012)

5 STEPS TO A 5: 500 AP Chemistry Questions to Know by Test Day! (2012)

Chapter 14. Data Interpretation (Questions 445–500)

Question 445 refers to the following situation.

A small sample of astatine was purified from an astatine containing ore in the lab. The pure astatine was stored at 25°C overnight. The next day, the sample was reanalyzed and found to have a significant quantity of bismuth. The sample was shipped to another lab for independent analysis, where the sample, six days after shipping, was found to have almost no astatine, a large quantity of bismuth, and a small quantity of lead.

445. Which of the following best accounts for the differences in analyses of the sample?

(A) The sample was not properly purified.

(B) The original sample was contaminated and some astatine was lost with each analysis.

(C) The astatine transmuted to bismuth, which transmuted to lead over the time course of analyses.

(D) The astatine sample was contaminated with bismuth during the first analysis and then the sample was further contaminated with bismuth and lead during the second analysis.

(E) The pure astatine sample was contaminated during the first analysis, but the analyses by the independent lab were mixed up with those of an unrelated sample from a completely different source.

Questions 446 and 447 refer to the following choices and the data table below.

A student forgot to label the flasks of 1.0-M concentrations of the following solutions:

(A) Fe3+(aq)

(B) Silver nitrate

(C) Barium chloride

(D) Mercury (I) nitrate

(E) Copper (II) nitrate

To identify each compound, the student mixed equal volumes of the 1.0-M solutions above, listed A–E, with a concentrated solution of NH3(aq). Each of the compounds was numbered 1–5.

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446. Compound 3

447. Compound 5

448. A student adds aqueous NH3 to a solution of Ni2+ ions and a precipitate forms. When the student adds excess NH3, the precipitate dissolves and produces a deep blue solution. Which of the following best explains why the precipitate dissolved in excess NH3?

(A) NH3 is a strong base at high concentrations.

(B) NH3 only acts as a base at low concentrations.

(C) Ni2+ forms a soluble, complex ion with NH3.

(D) Ni2+ solubility increases with increased pH.

(E) Ni2+ gets reduced by the excess NH3, forming soluble Ni atoms.

449. In the laboratory, which of the following can produce a gas when added to 1 M HCl?

I. Zn(s)

II. NaHCO3(s)

III. 1 M NH3(aq)

(A) I only

(B) III only

(C) I and II only

(D) I and III only

(E) I, II, and III

450. A solid, white crystalline substance is added to water to produce a basic solution. When a strong acid is added to the solution, a gas is liberated. Based on this information, the solid could be:

(A) NaCl

(B) NaOH

(C) NaNO3

(D) Na2CO3

(E) Na2SO4

Questions 451–453 refer to the following experiment.

An experiment analyzed the ratios in which iron and oxygen combine to form different compounds. The following data were obtained.

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451. This experiment best demonstrates which of the following chemical principles?

(A) Conservation of mass

(B) Conservation of energy

(C) The law of definite proportions

(D) The law of multiple proportions

(E) The law of stoichiometry

452. If no other information was available, which of the following could be determined from the data collected?

(A) Empirical formula

(B) Equilibrium constant

(C) Reaction order

(D) Enthalpy of formation

(E) Density

453. The compounds that were formed during the experiment were

I. FeO

II. FeO2

III. Fe2O

IV. Fe2O3

V. Fe3O4

(A) I, II, and IV

(B) I, III, and IV

(C) I, III, and V

(D) II, III, and V

(E) III, IV, and V

Questions 454–456 refer to the following experiment.

A student weighed 13 grams of blue CoCl2 and placed it on a watch glass at room temperature. Within a few minutes, she observed that the compound turned purple. When she re-weighed the sample, it weighed 17 grams. Several minutes later, it turned red. When she weighed the sample a third time, it weighed 24 grams.

454. The CoCl2 compound can be described as all of the following except:

(A) Deliquescent

(B) Hygroscopic

(C) Desiccant

(D) Efflorescent

(E) Hydrophilic

455. The correct formulas of the purple and red hydrates the student observed are:

(A) CoCl2.1 H2O and CoCl2.3 H2O

(B) CoCl2.2 H2O and CoCl2.6 H2O

(C) CoCl2.4 H2O and CoCl2.7 H2O

(D) CoCl2.4 H2O and CoCl2.11 H2O

(E) CoCl2.17 H2O and CoCl2.24 H2O

456. Ionic compounds that undergo a significant color change when hydrated have which of the following properties?

(A) They contain a metal and a nonmetal.

(B) They contain a transition metal.

(C) They form only one kind of hydrate.

(D) They are more efflorescent than deliquescent.

(E) They contain polyatomic ions.

Questions 457 and 458 refer to the following experiment.

A student performed an experiment at 760 torr. He obtained a sample of an unknown, volatile liquid. He placed it in a 2.00-L Erlenmeyer flask and covered it with a lid containing a tiny pinhole. The student placed the flask in boiling water of 100°C until all the air in the flask escaped through the pinhole and all of the liquid was vaporized. He then immersed the flask in cold water to condense the gas. He dried the flask and determined the mass of the condensed vapor.

457. The mass of the condensed vapor was 3.0 grams. What is the molar mass of the liquid?

(A) 30 g mol−1

(B) 46 g mol−1

(C) 62 g mol−1

(D) 128 g mol−1

(E) 190 g mol−1

458. All of the following could result in the stated deviation from the actual molar mass except:

(A) The student left some of the unknown substance in the liquid phase before immersing in the cold water, increasing the observed molar mass.

(B) The container’s lid was not securely attached to the flask, decreasing the observed molar mass.

(C) The substance had not actually heated up to 100°C in the water bath as the student had thought, decreasing the observed molar mass.

(D) The student did not properly dry the flask before adding the unknown, increasing the observed molar mass.

(E) The student allowed some of the vapor to escape, decreasing the observed molar mass.

459. A student added 10 grams of an unknown, nonvolatile solute to 50 grams of water. At 760 torr, the solution boiled at 102°C. If the solute was known to be an ionic compound with a van’t Hoff dissociation factor of 2, the molar mass of the solute is closest to:

(A) 72 g mol−1

(B) 101 g mol−1

(C) 204 g mol−1

(D) 372 g mol−1

(E) 500 g mol−1

Questions 460–464 refer to the following graph.

The data below were obtained in the determination of the freezing point of a solution of naphthalene in para-dichlorobenzene. (Assume the compounds do not dissociate in the solution.)

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460. What is the freezing point of pure naphthalene (°C)?

(A) 90

(B) 85

(C) 80

(D) 70

(E) 65

461. The freezing point (°C) of the naphthalene-para-dichlorobenzene solution is closest to:

(A) 80

(B) 75

(C) 70

(D) 65

(E) <65

462. The molality of naphthalene is closest to which of the following? (The freezing point depression constant for para-dichlorobenzene is 7.1°C m−1.)

(A) 0.71

(B) 1.4

(C) 2.8

(D) 3.6

(E) 7.1

463. A solution is prepared by dissolving 20.0 g of a nondissociating solute in 100 g of a pure solvent with a Kf = 5.0°C m−1 and a freezing point of −25°C. The freezing point of the solution is −37.5°C. The molar mass of the solute is closest to:

(A) 63 g mol−1

(B) 80 g mol−1

(C) 108 g mol−1

(D) 120 g mol−1

(E) 180 g mol−1

464. Electromagenetic radiation in the form of X-rays can be passed through a crystal of a pure substance producing a diffraction pattern that can be captured on photographic paper and analyzed to determine molecular structure. Radiation of X-ray wavelength is used in this procedure because

(A) X-ray wavelengths are small enough to pass through the crystal.

(B) X-rays wavelengths are significantly greater than the size of the atoms so they can easily be reflected off the surface.

(C) diffraction patterns emerge from crystals only when the wavelength of the radiation is comparable in size to the distance between the atoms.

(D) the energy of X-rays is high enough to break the crystal apart and scatter the atoms into a pattern on the photographic paper.

(E) the energy of X-rays is large enough to ionize the crystal but not to break apart the bonds between atoms.

465. A student determined the percentage of water in a hydrate to be 26 percent by weighing the sample, heating it until dry, and then reweighing it. The accepted value for the percentage of water in the hydrate is 45 percent. Which of the following is the best explanation for the difference between measured and accepted values?

(A) The student had a high-percent error.

(B) The student started with a mass of sample that was too low to accurately weigh.

(C) Overheating of the sample caused some of the solid to spatter out of the crucible.

(D) Overheating of the sample caused the dry sample to decompose into a gas.

(E) The dehydrated sample absorbed moisture from the atmosphere between drying and reweighing.

466. In a laboratory, H2 gas can be produced by adding which of the following to a 1-M HCl solution?

I. Mg(s)

II. Zn(NO3)2(s)

III. Na2CO3(s)

(A) I only

(B) II only

(C) III only

(D) I and II only

(E) II and III only

Questions 467 and 468 refer to the answer choice listed in the table below and the following titration curve.

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467. Which of the above indicators is the most appropriate choice for this titration?

468. Which of the above indicators would transition in the buffer region of the curve?

Question 469 refers to the following analysis.

A colorless solution was aliquoted into 3 test tubes. The following tests were performed:

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469. Which of the following ions could be present in the solution at a 0.15-M concentration?

(A) CO32–

(B) Na+

(C) Ca2+

(D) Ni2+

(E) Ba2+

Questions 470–472 to refer to the following experimental procedure.

In a laboratory experiment, H2 gas is produced by the following reaction:

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The H2 gas is collected over water in a gas-collection tube (eudiometer). The atmospheric pressure in the laboratory is 770 torr and the temperature of the lab and the water used in the experiment is 22°C. The vapor pressure of water is 19.8 torr at 22°C.

470. Before measuring the volume of gas collected in the tube, which of the following is a necessary step in correctly determining the total gas pressure inside the tube?

(A) Increase the temperature of the water to 25°C.

(B) Wait for the atmospheric pressure in the lab to reach 760 torr.

(C) Let air into the tube to break the vacuum.

(D) Adjust the tube so that the water level inside the tube is the same as the water level outside the tube.

(E) Lift the tube until the lip is just barely immersed in the water.

471. Which of the following gases should not be collected using this technique?

I. HCl

II. NH3

III. CO2

(A) I only

(B) II only

(C) III only

(D) I and II only

(E) II and III only

472. The partial pressure of hydrogen gas in the tube is closest to:

(A) 730 torr

(B) 750 torr

(C) 760 torr

(D) 770 torr

(E) The partial pressure cannot be determined without knowing the volume of gas collected

Questions 473–475 refer to the following experiment.

A student designed a procedure to determine the heat of fusion of ice. She constructed a calorimeter using a polystyrene cup and a thermometer. She weighed the cup, filled it with 150 mL of warm water, then weighed the cup and water together. The temperature of the water was measured, and then ice taken from an ice bath temporarily stored in a –20°C freezer was added to the cup. The cup with water and ice was weighed. The student then covered the cup with a polystyrene lid with two small openings. In one opening, she inserted a thermometer and in the other, she inserted a stirring rod to gently stir the contents of the cup until all the ice was melted. The lowest temperature reached by the water in the cup was recorded.

473. The purpose of weighing the cup and its contents the third (last) time was to

(A) determine the mass of water that was added.

(B) determine the mass of ice that was added.

(C) determine the mass of ice and water that were added.

(D) determine the mass of the calorimeter and thermometer.

(E) determine the mass of water that evaporated while the lid was off the cup.

474. Suppose a significant amount of water from the ice bath adhered to the ice cubes that the student added to the calorimeter. How would this affect the value of the heat of fusion of ice is calculated?

(A) There would be no effect because the water from the bath would be at the same temperature as the ice cubes.

(B) The calculated value would be too large because less warm water needed to be cooled.

(C) The calculated value would be too large because more cold water needed to be heated.

(D) The calculated value would be too small because more cold water needed to be heated.

(E) The calculated value would be too small because less ice melted than was weighed.

The student’s final data is recorded below.

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475. Which of the following pieces of information is necessary to calculate the heat of fusion of ice from this data?

I. The specific heat of water

II. The specific heat of ice

III. The thermal conductivity of water

IV. The thermal expansion coefficient of ice

(A) I only

(B) II only

(C) I and II only

(D) I and III only

(E) I, II, and IV only

476. What mass of KOH (molar mass 56 g mol−1) is required to make 250 mL of a 0.400 M KOH solution?

(A) 1.00 g

(B) 5.60 g

(C) 8.96 g

(D) 14.0 g

(E) 22.4 g

477. A steady electric current is passed through molten NaCl for exactly 2 hours producing 230 g of Na metal. The same current is passed through molten FeCl3 for exactly 2 hours. The mass of Fe metal expected to be produced is closest to:

(A) 56 g

(B) 112 g

(C) 168 g

(D) 186 g

(E) 224 g

478. When 100 mL of 2 M Pb(NO3)2 is mixed with 100 mL of 3 M NaCl in a beaker, a white precipitate forms. Which of the following is true of the concentration of ions remaining in solution?

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479. Which of the following would be a qualitative test for a solution of Ba2+, Fe3+, and Zn2+ ions that would separate Ba2+ from the other ions at room temperature?

I. Adding dilute HCl

II. Adding dilute NaOH

III. Adding dilute Li2SO4

(A) I only

(B) II only

(C) III only

(D) II and III only

(E) I, II, and III

A discharge tube filled with only hydrogen gas was electrified. The gas gave off blue light, which was polarized and then passed through a prism. Four narrow, colored bands were observed on a screen behind the prism. The energy of a photon is given by the equation E = hν, where h = 6.63 × 10−34 J.s and v = the frequency.

The following data were collected during the experiment.

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480. Which of the following best explains why hydrogen gas emitted light when electrified?

(A) For energy to be conserved in an atom, photons are emitted when an electron drops to ground state after being excited.

(B) Electrons absorbed photons of electricity that provided the energy needed for them to be ejected.

(C) The ionized gases produced by the electric current emit photons.

(D) The electricity caused the gas particles to collide with great kinetic energy, producing photons.

(E) The electrons turned into photons when subjected to an electric field.

481. Wave-like properties of light include which of the following?

I. Interference

II. Polarization

III. The photoelectric effect

(A) I only

(B) II only

(C) III only

(D) I and II only

(E) II and III only

482. In another famous experiment, a metal plate was bombarded with photons of different frequencies. At frequencies above 4.4 × 1014 sec−1, electrons were ejected from the metal, hence ionizing it. Which of the following is closest to the ionization energy of the metal in Joules?

(A) 1.5 × 10−48

(B) 6.6 × 10−34

(C) 4.4 × 10−20

(D) 2.9 × 10−19

(E) 3.0 × 10−14

483. A photon of red light is produced by an atom. Which of the following expressions accurately calculates its energy?

(A) (4.6 × 1014) (656)

(B) (4.6 × 1014) (6.63 × 10−34)

(C) (4.6 × 1014) (3 × 108)

(D) (656) (6.63 × 10−34)

(E) (656) (6.63 × 10−34)

484. All of the following are true statements regarding atomic spectra except:

(A) Line spectra are typical of electrified gases and continuous spectra are produced from the glow of hot objects.

(B) The electron configuration of the atom determines the type of spectra that will be emitted.

(C) The number of lines in the spectra is directly proportional to the number of electrons in the atom.

(D) Photons with lower wavelengths than those of visible light can be can be emitted by atoms.

(E) The lines produced in atomic spectra support the quantum mechanical model of that atom that says there are achievable energy states.

485. Which of the following is true regarding the polarization of the blue light in the experiment?

(A) Monochromatic light (one color) must be polarized in order to pass it through a prism.

(B) The polarizer focuses the light so it hits the prism in a more intense band.

(C) Polarization filters waves of light so that only waves oriented in the same plane emerge from the polarizer.

(D) The polarizer is a weak prism that partially separates the different wavelengths of light so that the prism can separate them more effectively.

(E) The polarizer absorbs wavelengths of light that are not in the visible range to prevent them from entering the prism.

Questions 486–488 refer to the following experiment.

A beam of gaseous hydrogen atoms is emitted from a hot furnace and passed through a magnetic field onto a detector screen. The interaction of the electron of the hydrogen atom and the magnetic field causes the hydrogen atom to be deflected from a straight line path. A tiny, permanent spot develops where an atom strikes the screen.

486. If the spin of the electron in a hydrogen atom (only 1 electron) was completely random, which of the following patterns would be observed on the screen?

(A) One very small, focused spot in the middle of the screen

(B) A very dark spot in the center of the screen that becomes more diffused as the radius increases

(C) No discrete spots would be observed

(D) Two spots of equal intensity

(E) A line in the shape of a wave

487. Which of the following observations was the experiment designed to further study?

(A) The energy of atoms is quantized.

(B) Electrons have both wave- and particle-like properties.

(C) It is impossible to know both the position and momentum of an electron with certainty.

(D) Electrons have a charge equal in magnitude but opposite in charge to protons, but their mass is 1/1,800 that of a proton.

(E) Emission spectra lines of hydrogen and sodium can be split when a magnetic field is applied.

488. The data produced in this experiment verify which of the following concepts of the atom?

(A) Electron energies are quantized.

(B) Electron spin is either +½ or −½.

(C) Electrons occupy orbits around the nucleus.

(D) Electrons have properties of both waves and particles.

(E) The more that is known about an electron’s position, the less can be known of its momentum (or velocity).

489. Particle-like properties of light include which of the following?

I. Interference

II. Polarization

III. The photoelectric effect

(A) I only

(B) II only

(C) III only

(D) I and II only

(E) II and III only

Questions 490–493 refer to the following experiment.

A cathode ray strikes a detector in a straight line, but when a magnetic or electric field is applied, the path of the ray is deflected.

490. Accurate interpretations of this observation include:

I. Cathode ray particles are charged.

II. Cathode rays have both wave- and particle-like properties.

III. Cathode rays are composed of electrons.

(A) I only

(B) II only

(C) III only

(D) I and II only

(E) I and III only

491. The experiment revealed a charge-to-mass ratio of −1.76 × 108 C g−1. The charge of an individual electron is −1.602 × 10−19 C. Which of the following correctly expresses the mass of an individual electron?

(A) (−1.602 × 10−19) (−1.76 × 108)

(B) (−1.602 × 10−19) (−1.76 × 108)−1

(C) (−1.76 × 108) (−1.602 × 10−19)−1

(D) (−1.602 × 10−19) (−1.76 × 108)−1(6.02 × 1023)

(E) (−1.602 × 10−19) (−1.76 × 108) (6.02 × 1023)

492. Which of the following particles would not be deflected when passed through an electric field?

(A) α (alpha) particle

(B) β (beta) particle

(C) Proton

(D) Neutron

(E) Positron

Questions 493–498 refer to the following data collected at 20°C.

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493. The liquid with the steepest meniscus in a glass tube of small diameter

494. The liquid with the greatest resistance to flow

495. The liquid with the greatest intermolecular forces of attraction

496. Which pair of liquids listed below is miscible?

(A) Benzene and water

(B) Water and olive oil

(C) Castor oil and glycerol

(D) Benzene and glycerol

(E) Water and glycerol

497. The expected surface tension (in N/m) of castor oil is approximately:

(A) <0.02

(B) Between 0.020 and 0.032

(C) Between 0.033 and 0.064

(D) Between 0.065 and 0.073

(E) >0.074

498. Viscosity and surface tension decrease with increasing temperature. This is most accurately explained by the fact that

(A) liquids expand when heated, increasing the distance between the molecules.

(B) both viscosity and surface tension are primarily determined by the intermolecular forces of attraction between the molecules in the liquid.

(C) density decreases with increasing temperature, allowing the molecules to flow more freely past each other.

(D) increasing temperature increases reaction rates.

(E) increasing temperature increases the Keq of the equilibrium state of both the viscosity and surface tension.

Questions 499 and 500 refer to the following answer choices:

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499. A weak acid

500. The best electrolyte