AP Chem Final

The oxidation state that is common to aqueous ions of Fe, Mn, and Zn is

+2

C2H4(g) + 3 O2(g) 2 CO2(g) + 2 H2O(g) For the reaction of ethylene represented above, H is -1,323 kJ. What is the value of H if the combustion produced liquid water H2O(l) ? (H for the phase change H2O(g) H2O(l) is -44 kJ mol-1.)

-1,411 kJ

2 KClO3(s) 2 KCl(s) + 3 O2(g) According to the equation above, how many moles of potassium chlorate, KClO3, must be decomposed to generate 1.0 L of O2 gas at standard temperature and pressure?

(2/3)(1/22.4) mol

The boiling points of the elements helium, neon, argon, krypton, and xenon increase in that order. Which of the following statements accounts for this increase?

The London (dispersion) forces increase.

A hot-air balloon rises. Which of the following is the best explanation for this observation?

The air density inside the balloon is less than that of the surrounding air.

Which of the following best describes what happens to the substance between t4 and t5?

The molecules are leaving the liquid phase.

At standard temperature and pressure, a 0.50 mol sample of H2 gas and a separate 1.0 mol sample of O2 gas have the same

average molecular kinetic energy

All of the halogens in their elemental form at 25oC and 1 atm are

diatomic molecules

The diagram above represents H2(g) and N2(g) in a closed container. Which of the following diagrams would represent the results if the reaction shown below were to proceed as far as possible? N2(g) + 3 H2(g) --> 2 NH3(g)

just pick the picture that has 2NH3 and 2H2

The volume of distilled water that should be added to 10.0 mL of 6.00 M HCl(aq) in order to prepare a 0.500 M HCl(aq) solution is approximately

110. mL

___C10H12O4S (s) + ___O2 (g) ___CO2 (g) + ___SO2 (g) + ___H2O (g) When the equation above is balanced and all coefficients are reduced to their lowest whole-number terms, the coefficient for O2 (g) is

12

CS2(l) + 3 O2(g) CO2(g) + 2 SO2(g) What volume of O2(g) is required to resact with excess CS2(l) to produce 4.0 L of CO2(g)? (Assume all gases are measured at 0oC and 1 atm.)

12 L

Which of the following pieces of laboratory glassware should be used to most accurately measure out a 25.00 mL sample of a solution

25 mL pipet

The atomic mass of copper is 63.55. Given that there are only two naturally occurring isotopes of copper, 63Cu and 65Cu, the natural abundance of the 65Cu isotope must be approximately

25%

How many milliliters of 11.6-molar HCl must be diluted to obtain 1.0 L of 3.0-molar HCl?

260 mL

The weight of H2SO4 (molecular weight 98.1) in 50.0 milliliters of a 6.00-molar solution is

29.4 g

Can be used to predict that a gaseous carbon atom in its ground state is paramagnetic

Hund's rule (principle of maximum multiplicity)

Which of the following describes the changes in forces of attraction that occur as H2O changes phase from a liquid to a vapor?

Hydrogen bonds between H2O molecules are broken.

In which of the following species does sulfur have the same oxidation number as it does in H2SO4?

SO2Cl2

Which of the following elements combines with oxygen to form a covalent network solid?

Si

Of the following pure substances, which has the highest melting point?

SiO2

Which of the following ions has the same number of electrons as Br?

Sr2+

Carbon dioxide, CO2(s)

Strong multiple covalent bonds (including p-bonds) with weak intermolecular forces

Methane, CH4 (s)

Strong single covalent bonds with weak intermolecular forces

The atom that contains exactly two unpaired electrons

S

For which of the following molecules are resonance structures necessary to describe the bonding satisfactorily?

SO2

Which of the following gases deviates most from ideal behavior?

SO2

A sample of 9.00 grams of aluminum metal is added to an excess of hydrochloric acid. The volume of hydrogen gas produced at standard temperature and pressure is

11.2 liters

Based on the information above, what is the standard enthalpy change for the following reaction? Na2O(s) + H2O(l) 2 NaOH(s)

-150 kJ

I2(g) + 3 Cl2(g) 2 ICl3 (g) According to the data in the table below, what is the value of H° for the reaction above?

-382 kJ

3 C2H2(g) C6H6(g) What is the standard enthalpy change, Ho, for the reaction represented above? Hof of C2H2(g) is 230 kJ mol-1; Hof of C6H6(g) is 83 kJ mol-1.)

-607 kJ

CH4(g) + 2 O2(g) CO2(g) + 2 H2O(l); H = - 889.1 kJ Hf° H2O(l) = - 285.8 kJ / mole Hf° CO2(g) = - 393.3 kJ / mole What is the standard heat of formation of methane, Hf° CH4(g), as calculated from the data above?

-75.8 kJ/mol

2 H2O(l) + 4 MnO4-(aq) + 3 ClO2-(aq) 4 MnO2(s) + 3 ClO4-(aq) + 4 OH-(aq) According to the balanced equation above, how many moles of ClO2-(aq) are needed to react completely with 20. mL of 0.20 M KMnO4 solution?

0.0030 mol

A 360. mg sample of aspirin, C9H8O4, (molar mass 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

3 Ag(s) + 4 HNO3 3 AgNO3 + NO(g) + 2 H2O The reaction of silver metal and dilute nitric acid proceeds according to the equation above. If 0.10 mole of powdered silver is added to 10. milliliters of 6.0-molar nitric acid, the number of moles of NO gas that can be formed is

0.015 mol

What is the final concentration of barium ions, [Ba2+], in solution when 100. mL of 0.10 M BaCl2(aq) is mixed with 100. mL of 0.050 M H2SO4(aq)?What is the final concentration of barium ions, [Ba2+], in solution when 100. mL of 0.10 M BaCl2(aq) is mixed with 100. mL of 0.050 M H2SO4(aq)?

0.025 M

The alkenes are compounds of carbon and hydrogen with the general formula CnH2n. If 0.561 gram of any alkene is burned in excess oxygen, what number of moles of H2O is formed?

0.0400 mol

How many moles of solid Ba(NO3)2 should be added to 300. milliliters of 0.20-molar Fe(NO3)3 to increase the concentration of the NO3¯ ion to 1.0-molar? (Assume that the volume of the solution remains constant.)

0.060 mol

A solution is prepared by adding 16 g of CH3OH (molar mass 32 g) to 90. g of H2O (molar mass 18 g). The mole fraction of CH3OH in this solution is closest to which of the following?

0.1

Which of the following aqueous solutions has the highest boiling point?

0.10 M potassium sulfate, K2SO4

5 Fe2+ + MnO4¯ + 8 H+ 5 Fe3+ + Mn2+ + 4 H2O In a titration experiment based on the equation above, 25.0 milliliters of an acidified Fe2+ solution requires 14.0 milliliters of standard 0.050-molar MnO4¯ solution to reach the equivalence point. The concentration of Fe2+ in the original solution is

0.14 M

A 20.0-milliliter sample of 0.200-molar K2CO3 solution is added to 30.0 milliliters of 0.400-molar Ba(NO3)2 solution. Barium carbonate precipitates. The concentration of barium ion, Ba2+, in solution after reaction is

0.160 M

If 200. mL of 0.60 M MgCl2(aq) is added to 400. mL of distilled water, what is the concentration of Mg2+(aq) in the resulting solution? (Assume volumes are additive.)

0.20 M

W(g) + X(g) Y(g) + Z(g) Gases W and X react in a closed, rigid vessel to form gases Y and Z according to the equation above. The intial pressure of W(g) is 1.20 atm and that of X(g) is 1.60 atm. No Y(g) or Z(g) is initially present. The experiment is carried out at constant temperature. What is the partial pressure of Z(g) when the partial pressure of W(g) has decreased to 1.0 atm?

0.20 atm

A sample of 0.0100 mole of oxygen gas is confined at 37° C and 0.216 atmosphere. What would be the pressure of this sample at 15° C and the same volume?

0.201 atm

If 0.40 mol of H2 and 0.15 mol of O2 were to react completely as possible to produce H2O, what mass of reactant would remain?

0.21 g of H2

In which of the following groups are the three species isoelectronic; i.e., have the same number of electrons?

S2-, K+, Ca2+

What is the mole fraction of ethanol, C2H5OH, in an aqueous solution that is 46% ethanol by mass? (The molar mass of C2H5OH is 46 g; the molar mass of H2O is 18 g.)

0.25

What number of moles of O2 is needed to produce 14.2 grams of P4O10 from P? (Molecular weight P4O10 = 284)

0.250 mol

A 40.0 mL sample 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? (Assume that the volumes are additive.)

0.28 M

A 1.0 L sample of an aqueous solution contains 0.10 mol of NaCl and 0.10 mol of CaCl2. What is the minimum number of moles of AgNO3 that must be added to the solution in order to precipitate all of the Cl- as AgCl (s) ? (Assume that AgCl is insoluble.)

0.30 mol

A gaseous mixture containing 7.0 moles of nitrogen, 2.5 moles of oxygen, and 0.50 mole of helium exerts a total pressure of 0.90 atmosphere. What is the partial pressure of the nitrogen?

0.63 atm

Commercial vinegar was titrated with NaOH solution to determine the content of acetic acid, HC2H3O2. For 20.0 milliliters of the vinegar 26.7 milliliters of 0.600-molar NaOH solution was required. What was the concentration of acetic acid in the vinegar if no other acid was present?

0.800 M

How many carbon atoms are contained in 2.8 g of C2H4?

1.2 x 10^23

.....Mg(s) + .....NO3¯(aq) +.....H+(aq) --->......Mg2+(aq) + ....NH4+(aq) + ....H2O(l) When the skeleton equation above is balanced and all coefficients reduced to their lowest whole-number terms. what is the coeficient for H+ ?

10

2 MnO4-(aq) + 10 Br -(aq) + 16 H+(aq) 2 Mn2+(aq) + 5 Br2(aq) + 8 H2O(l) How many electrons are transferred in the reaction represented by the balanced equation above?

10

How many mL of 10.0 M HCl are needed to prepare 500. mL of 2.00 M HCl?

100. mL

The pH of a solution prepared by the addition of 10. mL of 0.002 M KOH(aq) to 10. mL of distilled water is closest to

11

The system shown above is at equilibrium at 28 °C. At this temperature, the vapor pressure of water is 28 millimeters of mercury. The partial pressure of O2(g) in the system is

133 mm Hg

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 800 mm Hg. What is the partial pressure of the SO2(g) in the flask?

160 mm Hg

The mass of element Q found in 1.00 mole of each of four different compounds is 38.0 grams, 57.0 grams, 76.0 grams, and 114 grams, respectively. A possible atomic weight of Q is

19.0

What mass of Au is produced when 0.0500 mol of Au2S3 is reduced completely with excess H2?

19.7 g

Represents an atom that is chemically unreactive

1s 2s 2p

Represents an atom that has four valence electrons

1s 2s 2p ___

Represents an atom in an excited state

1s __ 2s __

Of the following electron configurations of neutral atoms, which represents an atom in an excited state?

1s2 2s2 2p5 3s2

The ground-state configuration of a negative ion of a halogen

1s2 2s2 2p5 3s2 3p5

An impossible electronic configuration

1s2 2s2 2p6 2d10 3s2 3p6

The ground-state configuration of a common ion of an alkaline earth element

1s2 2s2 2p6 3s2 3p6

The ground-state configuration for the atoms of a transition element

1s2 2s2 2p6 3s2 3p6 3d3 4s2

Which of the following represents the ground state electron configuration for the Mn3+ ion? (Atomic number Mn = 25)

1s2 2s2 2p6 3s2 3p6 3d4

The net ionic equation for the reaction between silver carbonate and hydrochloric acid is

2 Ag+ + CO32¯ + 2 H+ + 2 Cl¯ --> 2 AgCl(s) + H2O + CO2(g)

An oxidation-reduction reaction that is also a synthesis reaction

2 Mg(s) + O2(g) 2 MgO(s)

Mass of an empty container = 3.0 grams Mass of the container plus the solid sample = 25.0 grams Volume of the solid sample = 11.0 cubic centimeters The data above were gathered in order to determinethe density of an unknown solid. The density of the sample should be reported as

2.00 g/cm3

What is the molarity of a solution of phosphoric acid, H3PO4, that contains 24.5 g of phosphoric acid (molar mass 98.0 g) in 100. g of H2O?

2.50 m

A combustion reaction

S8(s) + 8 O2(g) --> 8 SO2

___Li3N (s) + ___H2O (l) ___Li+ (aq) + ___OH- (aq) + ___NH3 (g) When the equation above is balanced and all coefficients reduced to lowest whole number terms, the coefficient for OH- (aq) is

3

A reaction in which the same reactant undergoes both oxidation and reduction

3 Br2(aq) + 6 OH-(aq) --> 5 Br-(aq) + BrO3-(aq) + 3 H2O(l)

NH4NO3(s) N2O(g) + 2 H2O(g) A 0.03 mol sample of NH4NO3(s) is placed in a 1 L evacuated flask, which is then sealed and heated. The NH4NO3(s) 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? (The value of the gas constant, R, is 0.082 L atm mol-1 K-1.)

3 atm

As the temperature is raised from 20 ° C to 40 ° C, the average kinetic energy of neon atoms changes by a factor of

313/293

...Fe(OH)2 + ... O2 + ... H2O ... Fe(OH)3 If 1 mole of O2 oxidizes Fe(OH)2 according to the reaction represented above, how many moles of Fe(OH)3 can be formed?

4

...H+(aq) + ...NO2-(aq) + ... Cr2O72-(aq) ...Cr3+(aq) + ...NO3-(aq) + ...H2O(l) When the equation above is balanced and all coefficients are reduced to lowest whole numbers, the coefficients for H2O(l) is

4

The atom that contains only one electron in the highest occupied energy sublevel

4

The density of a pure liquid at 25°C was calculated by determining the mass and volume of a sample of the liquid. A student measure the mass of a clean, dry 25.00 mL volumetric flask, filled the flask to its calibration mark with the liquid, and then measured the mass of the flask and the liquid. The recorded measurements are shown in the table above. On the basis of this information, to how many significant figures should the density of the liquid be reported?

4

If 87 g of K2SO4 (molar mass 174 g) is dissolved in enough water to make 250 mL of solution, what are the concentrations of potassium and sulfate ion respectively?

4.0 and 2.0 M

2 K + 2 H2O 2 K+ + 2 OH¯ + H2 When 0.400 mole of potassium reacts with excess water at standard temperature and pressure as shown in the equation above, the volume of hydrogen gas produced is

4.48 L

When 70. milliliter of 3.0-molar Na2CO3 is added to 30. milliliters of 1.0-molar NaHCO3 the resulting concentration of Na+ is

4.5 M

What volume of 0.150-molar HCl is required to neutralize 25.0 mililiters of 0.120-molar Ba(OH)2?

40.0 mL

How many grams of calcium nitrate, Ca(NO3)2, contains 24 grams of oxygen atoms?

41 g

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 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2.00 liters

An excess of Mg(s) is added to 100. mL of 0.400 M HCl. At 0oC and 1 atm pressure, what volume of H2 gas can be obtained?

448 mL

A sample of 3.30 grams of an ideal gas at 150.0 °C and 1.25 atmospheres pressure has a volume of 2.00 liters. What is the molar mass of the gas? The gas constant, R, is 0.0821 L atm mol¯1 K¯1).

45.8 g/mol

The density of an unknown gas is 4.20 grams per liter at 3.00 atmospheres pressure and 127 °C. What is the molecular weight of this gas? (R = 0.0821 liter-atm / mole-K)

46.0

A 2.00-liter sample of nitrogen gas at 27 °C and 600. millimeters of mercury is heated until it occupies a volume of 5.00 liters. If the pressure remains unchanged, the final temperature of the gas is

477 °C

...CrO2¯ + ...OH¯ ... CrO42¯ + ... H2O + ... e¯ When the equation for the half-reaction above is balanced, what is the ratio of the coefficients OH¯ / CrO2¯ ?

4:1

Propane gas, C3H8, burns in excess oxygen gas. When the equation for this reaction is correctly balanced and all coefficients are reduced to their lowest whole-number term, the coefficient for O2 is

5

Equal masses of He and Ne are placed in a sealed container. What is the partial pressure of He if the total pressure in the container is 6 atm?

5 atm

10 HI + 2 KMnO4 + 3 H2SO4 5 I2 + 2 MnSO4 + K2SO4 + 8 H2O According to the balanced equation above, how many moles of HI would be necessary to produce 2.5 mol of I2, starting with 4.0 mol of KMnO4 and 3.0 mol of H2SO4 ?

5.0

Which of the following shows the correct number of protons, neutrons, and electrons in a neutral cesium-134 atom?

55 protons, 79 neutrons, 55 electrons

. . . Ag+ + . . . AsH3(g) + . . . OH¯ . . . Ag(s) + . . . H3AsO3(aq) + . . . H2O When the equation above is balanced with lowest whole-number coefficients, the coefficient for OH¯ is

6

Approximately what mass of CuSO4•5H2O (250 g mol-1) is required to prepare 250 mL of 0.10 M copper(II) sulfate solution?

6.2 g

__ Cr2O72¯ + __ e¯ + __ H+ __ Cr3+ + __ H2O(l) When the equation for the half reaction above is balanced with the lowest whole-number coefficients, the coefficient for H2O is

7

A measured mass of an unreactive metal was dropped into a small graduated cylinder half filled with water. The following measurements were made. Mass of metal = 19.611 grams Volume of water before addition of metal = 12.4 milliliters Volume of water after addition of metal = 14.9 milliliters The density of the metal should be reported as

7.8 grams per mL

__ CH3CH2COOH(l) + __ O2(g) __ CO2(g) + __ H2O(l) How many moles of O2 are required to oxidize 1 mole of CH3CH2COOH according to the reaction represented above?

7/2 mol

Hydrogen gas is collected over water at 24 °C. The total pressure of the sample is 755 millimeters of mercury. At 24 °C, the vapor pressure of water is 22 millimeters of mercury. What is the partial pressure of the hydrogen gas?

733 mm Hg

...Cr2O72-(aq) + ...H2S(g) + ...H+(aq) ...Cr3+(aq) + ...S(s) + ...H2O(l) When the equation above is correctly balanced and all coefficients are reduced to lowest whole-number terms, the coefficient for H+(aq) is

8

It is suggested that SO2 (molar mass 64 grams), which contributes to acid rain, could be removed from a stream of waste gases by bubbling the gases through 0.25-molar KOH, therby producing K2SO3 . What is the maximum mass of SO2 that could be removed by 1,000 liters of the KOH solution?

8.0 kg

Under which of the following conditions of temperature and pressure would 1.0 mol of the real gas CO2(g) behave most like an ideal gas?

800 K, 0.1 atm

When a 1.00 gram sample of limestone was dissolved in acid, 0.38 grams of CO2 was generated. If the rock contained no carbonate other than CaCO3 , what was the percent of CaCO3 by mass in the limestone?

86%

2 N2H4(g) + N2O4(g) 3 N2(g) + 4 H2O(g) When 8.0 g of N2H4 (32 g mol-1) and 92 g of N2O4 (92 g mol-1) are mixed together and react according to the equation above, what is the maximum mass of H2O that can be produced?

9.0 g

Silicon dioxide, SiO2

A network solid with covalent bonding.

Which of the following represents acceptable laboratory practice?

Adding a weighed quantity of solid acid to a titration flask wet with distilled water.

Ionization Energies for the element X (kJ mol-1) The ionization energies for the element X are listed in the table above. On the basis of the data, element X is most likely to be

Al

Is added to silicon to enhance its properties as a semiconductor

As

Which of the following properties generally decreases across the periodic table from sodium to chlorine?

Atomic radius

Which of the following conclusions can be drawn from J. J. Thomson's cathode ray experiments?

Atoms contain electrons

A compound contains 30. percent sulfur and 70. percent fluorine by mass. The empirical formula of the compound is

SF4

On the basis of strength of intermolecular forces, which of the following elements would be expected to have the highest melting point?

Br2

Liquid naphthalene at 95oC was cooled to 30oC, as represented in the cooling curve above. From which section of the curve can the melting point of naphthalene be determined?

C

In which of the following processes are covalent bonds broken?

C (diamond) C (g)

The molecule with only one double bond

C2H4

Which of the following molecules contains only single bonds?

C2H5

A hydrocarbon gas with an empirical formula CH2 has a density of 1.88 grams per liter at 0 °C and 1.00 atmosphere. A possible formula for the hydrocarbon is

C3H6

A 27.0-gram sample of an unknown hydrocarbon was burned in excess oxygen to form 88.0 grams of carbon dioxide and 27.0 grams of water. What is a possible molecular formula of the hydrocarbon?

C4H5

Which of the following molecules has a dipole moment of zero?

C6H6 (benzene)

Sodium chloride is LEAST soluble in which of the following liquids?

CCl4

Which of the following does NOT behave as an electrolyte when it is dissolved in water?

CH3OH

Pi bonding occurs in each of the following species EXCEPT

CH4

Has an average atomic or molecular speed closest to that of N2 molecules at 0o and 1 atm

CO

A 2 L container will hold about 4 g of which of the following gases at 0oC and 1 atm?

CO2

Which of the following is a nonpolar molecule that contains polar bonds?

CO2

Assume that you have an "unknown" consisting of an aqueous solution of a salt that contains one of the ions listed below. Which ions must be absent on the basis of each of the following observations of the "unknown"? The solution gives no apparent reaction with dilute hydrochloric acid.

CO3 2-

Of the following compounds, which is the most ionic?

CaCl2

Gold, Au(s)

Closely packed lattice with delocalized electrons throughout

The elements in which of the following have most nearly the same atomic radius?

Cr, Mn, Fe, Co

A 0.1-molar solution of which of the following ions is orange?

Cr2O7 2-

In which of the following compounds is the mass ratio of chromium to oxygen closest to 1.62 to 1.00 ?

CrO2

Which of the following techniques is the most appropriate for the recovery of solid KNO3 from an aqueous solution of KNO3?

Evaporation to dryness

Which of the following best helps to account for the fact that the F- ion is smaller than the O2- ion?

F- has a larger nuclear charge than O2- has.

Is a gas in its standard state at 298 K

Fluorine

The safest and most effective emergency procedure to treat an acid splash on skin is to do which of the following immediately?

Flush the affected area with water and then with a dilute NaHCO3 solution

The atom that contains only one electron in the highest occupied energy sublevel

Ga

The London (dispersion) forces are weakest for which of the following gases under the same conditions of temperature and pressure?

H2

The molecule with the largest dipole moment

H2O

The electron-dot structure (Lewis structure) for which of the following molecules would have two unshared pairs of electrons on the central atom?

H2S

Which of the following acids can be oxidized to form a stronger acid?

H2SO3

At 25°C and 1 atm, is a strong electrolyte in aqueous solution

HBr

Of the following molecules, which has the largest dipole moment?

HF

The liquefied hydrogen halides have the normal boiling points given above. The relatively high boiling point of HF can be correctly explained by which of the following?

HF molecules tend to form hydrogen bonds

The net ionic equation for the reaction that occurs during the titration of nitrous aicd with sodium hydroxide is

HNO2 + OH¯ --> NO2¯ + H2O

Predicts that it is impossible to determine simultaneously the exact position and the exact velocity of an electron

Heisenberg uncertainty principle

When hafnium metal is heated in an atmosphere of chlorine gas, the product of the reaction is found to contain 62.2 percent Hf by mass and 37.4 percent Cl by mass. What is the empirical formula for this compound?

HfCl3

Concentrations of colored substances are commonly measured by means of a spectrophotometer. Which of the following would ensure that correct values are for the measured absorbance? I. There must be enough sample in the tube to cover the entire light path. II. The instrument must be periodically reset using a standard. III. The solution must be saturated.

I and II only

The melting point of MgO is higher than that of NaF. Explanations for this observation include which of the following? I. Mg2+ is more positively charged than Na+. II. O2- is more negatively charged than F-. III. The O2- ion is smaller than the F- ion.

I and II only

Correct procedures for a titration include which of the following? I Draining a pipet by touching the tip to the side of the container used for the titration II Rinsing the buret with distilled water just before filling it with the liquid to be titrated. III Swirling the soluiton frequently during the titration.

I and III only

Appropriate uses of a visible-light spectrophotometer include which of the following? I. Determining the concentration of a solution of Cu(NO3)2 II. Measuring the conductivity of a solution of KMnO4 III. Determining which ions are present in a solution that may contain Na+, Mg2+, Al3+

I only

Molecules that have planar configurations include which of the following? I BCl3 II CHCl3 III NCl3

I only

To determine the molar mass of a solid monoprotic acid, a student titrated a weighed sample of the acid with standardized aquesous NaOH. Which of the following could explain why the student obtained a molar mass that was too LARGE? I. Failure to rinse all acid from the weighing paper into the titration vessel. II Addition of more water than was needed to dissolve the acid III Addition of some base beyond the equivalence point.

I only

Which of the following represents a pair of isotopes?

I. Atomic Number: 7, Mass Number: 13 II. Atomic Number: 7, Mass Number: 14

Given that a solution is 5 percent sucrose by mass, what additional information is necessary to calculate the molarity of the solution? I. The density of water II. The density of the solution III. The molar mass of sucrose

II and III

Appropriate laboratory procedures include which of the following? I. Rinsing a buret with distilled water just before filling it with the titrant for the first titration II. Lubricating glass tubing before inserting it into a stopper III. For accurate results, waiting until warm or hot objects have reached room temperature before weighing them

II and III only

Types of hybridization exhibited by the C atoms in propene, CH3CHCH2, include which of the following? I. sp II. sp2 III. sp3

II and III only

3 Cu(s) + 8 H+(aq) + 2 NO3-(aq) 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l) True statements about the reaction represented above include which of the following? I. Cu(s) acts as an oxidizing agent. II. The oxidation state of nitrogen changes from +5 to +2. III. Hydrogen ions are oxidized to form H2O(l).

II only

In the laboratory, H2(g) can be produced by adding which of the following to 1 M HCl(aq)? I. 1 M NH3(aq) II. Zn(s) III. NaHCO3(s)

II only

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? I. The average molecular mass of the gas II. The average distance between the molecules III. The average speed of the molecules

III only

The energy required to convert a ground-state atom in the gas phase to a gaseous positive ion

Ionization energy

Equal masses of three different ideal gases, X, Y, and Z, are mixed in a sealed rigid container. If the temperature of the system remains constant, which of the following statements about the partial pressure of gas X is correct?

It depends on the relative molecular masses of X, Y, and Z.

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

Is white and very soluble in water

KCl

Is purple in aqueous solution

KMnO4

Adding water to some chemicals can be dangerous because large amounts of heat are liberated. Which of the following does NOT liberate heat when water is added to it?

KNO3

On the basis of the solubility curves shown above, the greatest percentage of which compound can be recovered by cooling a saturated solution of that compound from 90o to 30o?

KNO3

The energy change that occurs in the coversion of an ionic solid to widely separated gaseous ions

Lattice energy

Cesium chloride, CsCl (s)

Lattice of positive and negative ions held together by electrostatic forces

Reacts with water to form a strong base

Lithium

In solid methane, the forces between neighboring CH4 molecules are best characterized as

London (dispersion) forces

Which of the elements above has the smallest ionic radius for its most commonly found ion?

Mg

1s2 2s2 2p6 3s2 3p3 Atoms of an element, X, have the electronic configuration shown above. The compound most likely formed with magnesium, Mg, is

Mg3X2

Forms a compound having the formula KXO4

Mn

Which of the following measure of concentration changes with temperature?

Molarity

Forms monatomic ions with 2- charge in solutions.

S

Forms oxides that are common air pollutants and that yield acidic solution in water

S

In a laboratory experiment, H2(g) is collected over water in a gas-collection tube as shown in the diagram above. The temperature of the water is 21°C and the atmospheric pressure in the laboratory is measured to be 772 torr. Before measuring the volume of the gas collected in the tube, what step, if any, must be taken to make it possible to determine the total gas pressure inside the tube?

Move the tube downward until the water level is the same inside and outside the tube

Which element exhibits the greatest number of different oxidation states?

N

Contains 1 sigma (s) and 2 pi (p) bonds

N2

Has the largest bond-dissociation energy

N2

Which of the following molecules has the shortest bond length?

N2

Which of the following oxides is a gas at 25oC and 1 atm?

N2O

The simplest formula for an oxide of nitrogen that is 36.8 percent nitrogen by weight is

N2O3

At 25 °C and 1 atm, has molecules with a pyramidal shape.

NH3

The Lewis dot structure of which of the following molecules shows only one unshared pair of valence electron?

NH3

Assume that you have an "unknown" consisting of an aqueous solution of a salt that contains one of the ions listed below. Which ions must be absent on the basis of each of the following observations of the "unknown"? No odor can be detected when a sample of the solution is added drop by drop to a warm solution of sodium hydroxide.

NH4+

The effective nuclear charge experienced by the outermost electron of Na is different than the effective nuclear charge experienced by the outermost electron of Ne. This difference best accounts for which of the following?

Na has a lower first ionization energy than Ne

When a hydrate of Na2CO3 is heated until all the water is removed, it loses 54.3 percent of its mass. The formula of the hydrate is

Na2CO3 7 H2O

Which of the following compounds is ionic and contains both sigma and pi covalent bonds?

NaCN

Has the greatest rate of effusion through a pinhole

Ne

What is the most electronegative element of the below?

O

Of the following single bonds, which is the LEAST polar?

O - F

Has a bond order of 2

O2

Which of the following molecules has an angular (bent) geometry that is commonly represented as a resonance hybrid of two or more electron-dot structures?

O3

Which of the following has a zero dipole moment?

PF5

The molecule that has trigonal pyramidal geometry

PH3

Equal numbers of moles of He(g), Ar(g), and Ne(g) 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?

PHe < PNe<PAr

Indicates that an atomic orbital can hold no more than two electrons

Pauli exclusion principle

A precipitation reaction

Pb2+(aq) + CrO42-(aq) --> PbCrO4(s)

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?

The average speed of the gas molecules remains the same

Two flexible containers for gases are at the same temperature and pressure. One holds 0.50 gram of hydrogen and the other holds 8.0 grams of oxygen. Which of the following statements regarding these gas samples is FALSE?

The average speed of the hydrogen molecules is the same as the average speed of the oxygen molecules.

After completing an experiment to determine gravimetrically the percentage of water in a hydrate, a student reported a value of 38 percent. The correct value for the percentage of water in the hydrate is 51 percent. Which of the following is the most likely explanation for this difference?

The dehydrated sample absorbed moisture after heating.

A student pipetted five 25.00-milliliter samples of hydrochloric acid and transferred each sample to an Erlenmeyer flask, diluted it with distilled water, and added a few drops of phenolphthalein to each. Each sample was then titrated with a sodium hydroxide solution to the appearance of the first permanent faint pink color. The following results were obtained. Volumes of NaOH Solution First Sample..................35.22 mLSecond Sample..............36.14 mLThird Sample.................36.13 mLFourth Sample..............36.15 mLFifth Sample..................36.12 mL Which of the following is the most probable explanation for the variation in the student's results?

The pipette was not rinsed with the HCl solution.

Which of the following is probably true for a solid solute with a highly endothermic heat of solution when dissolved in water?

The solid is more soluble at higher temperatures.

Which of the following characteristics is common to elemental sulfur, chlorine, nitrogen, and carbon?

They have oxides that are acid anhydrides.

Ca, V, Co, Zn, As Gaseous atoms of which of the elements above are paramagnetic?

V, Co, and As only

The metal calcium reacts with molecular hydrogen to form a compound. All of the following statements concerning this compound are true EXCEPT:

When added to water, it forms an acidic solution.

X = CH3-CH2-CH2-CH2-CH3 Y = CH3-CH2-CH2-CH2-OH Z = HO-CH2-CH2-CH2-OH Based on concepts of polarity and hydrogen bonding, which of the following sequences correctly lists the compounds above in the order of their increasing solubility in water?

X < Y < Z

Has the greatest density

Xe

Samples of F2 gas and Xe gas are mixed in a container of fixed volume. The initial partial pressure of the F2 gas is 8.0 atmospheres and that of the Xe gas is 1.7 atmospheres. When all of the Xe gas reacted, forming a solid compound, the pressure of the unreacted F2 gas was 4.6 atmospheres. The temperature remained constant. What is the formula of the compound?

XeF4

When a solution of sodium chloride is vaporized in a flame, the color of the flame is

Yellow

A solution is known to contain an inorganic salt of one of the following elements. The solution is colorless. The solution contains a salt of

Zn

The pressure, in atm, exerted by 1.85 mol of an ideal gas placed in a 3.00 L container at 35.0ºC is given by which of the following expressions?

[(1.85)(0.0821)(308)]/3.00 atm

Represents an atom of a transition metal.

[Ar] 4s 3d

Solid ethyl alcohol, C2H5OH

a molecular solid with hydrogen bonding

Are always radioactive

actinides

The cooling curve for a pure substance as it changes from a liquid to a solid is shown above. The solid and liquid coexist at

all points on the curve between Q and S

In a molecule in which the central atom exhibits sp3d2 hybrid orbitals, the electron pairs are directed toward the corners of

an octahedron

The best explanation for the fact that diamond is extremely hard is that diamond crystals

are giant molecules in which each atom forms strong covalent bonds with all of its neighboring atoms

The SbCl5 molecule has trigonal bipyramid structure. Therefore, the hybridization of Sb orbitals should be

dsp3

Are the most likely to form anions

halogens

Is used to explain the fact that the four bonds in methane are equivalent

hybridization

CH3CH2OH boils at 78 °C and CH3OCH3 boils at - 24 °C, although both compounds have the same composition. This difference in boiling points may be attributed to a difference in

hydrogen bonding

Is used to explain why the boiling point of HF is greater than the boiling point of HBr

hydrogen bonding

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 the

increasing the number of unshared pairs of electrons

Which of the following structural formulas represents an isomer of the compound that has the structural formula represented above?

isomer - same molecular formula but different chemical structure

In the periodic table, as the atomic number increases from 11 to 17, what happens to the atomic radius?

it decreases only

Are the most difficult to iodize in a given period of the periodic table

noble gases

Is used to explain the fact that the carbon-to-carbon bonds in benzene, C6H6, are identical

resonance

Substances X and Y that were in a solution were separated in the laboratory using the technique of fractional crystalization. This fractional crystalization is possible because substances X and Y have different

solubilities

What is the hybridization of the carbon atom in a molecule of ethyne, represented above?

sp

CCl4, CO2, PCl3, PCl5, SF6 Which of the following does not describe any of the molecules above?

square planar

The substance is at its normal freezing point at time

t2

The cooling curve above shows how the temperature of a sample varies with time as the sample goes through phase changes. The sample starts as a gas, and heat is removed at a constant rate. At which time does the sample contain the most liquid?

t4

If the temperature of an aqueous solution of NaCl is increased from 20oC to 90oC, which of the following statements is true?

the molality of the solution remains unchanged.

H2Se (g) + 4 O2F2 (g) SeF6 (g) + 2 HF (g) + 4 O2 (g) Which of the following is true regarding the reaction represented above?

the oxidation number of Se changes from -2 to +6

Which of the following is a correct interpretation of the results of Rutherford's experiments in which gold atoms were bombarded with alpha particles?

the positive charge of an atom is concentrated in a small region

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

The figure above shows two closed containers. Each contains the same volume of acetone in equilibrium with its vapor at the same temperature. The vapor pressure of the acetone is

the same in both because the temperature is the same

When diluting concentrated H2SO4, one should slowly add acid to a beaker of water rather than add water to a beaker of acid. The reason for this precaution is to ensure that

there is a sufficient volume of water to absorb to the heat released

The geometry of the SO3 molecule is best described as

trigonal planar

Is used to explain why iodine molecules are held together in the solid state

van der Waals forces (LD forces)

A compound is heated to produce a gas whose molecular weight is to be determined. The gas is collected by displacing water in a water-filled flask inverted in a trough of water. Which of the following is necessary to calculate the molecular weight of the gas, but does NOT need to be measured during the experiment?

vapor pressure of the water

When the actual gas volume is greater then the volume predicted by the ideal gas law, the explanation lies in the fact that the ideal gas law does NOT include a factor for molecular.

volume

Explains the experimental phenomenon of electron diffraction

wave nature of matter