Semester 2 AP Chem

6

...P4O10 + ...Ca(OH)2 = ...Ca3(PO4)2 + ...H2O when the chemical equation above is balanced, in terms of lowest whole-number coefficients, the coefficient for H2O is

Mg3X2

1s^2 2s^2 2p^6 3s^2 3p^3 Atoms of an element, X, have the electron configuration shown above. The compound most likely formed w/ magnesium, Mg, is

-46 kJ/mol

2NH3 = 3H2 + N2 (H298 = 92 kJ/mol) According to the info above, what is the standard enthalpy of formation, H, for NH3 at 298 K?

.015 mole

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

1 x 10^-7

A .10M solution of a weak monoprotic acid has a pH equal to 4.0. The ionization constant of, Ka, of the acid is

1.0 M

A .20 mol sample of MgCl2 and a .10 mol sample of KCl are dissolved in water and diluted to 500 mL. What is the concentration of Cl in the solution?

3 atm

A 2L sample of N2 and a 1 L sample of Ar, each originally at 1 atm and 0C, are combined in a 1L tank. If the temp is held constant, what is the total pressure of the gases in the tank?

CuSO4 (aq)

A white precipitate forms when BaCl2(aq) is added to an unknown blue solution. What could be the identity of the blue solution?

Ba

Atoms of Mg combine w/ atoms of F to form a compound. What atoms combine w/ atoms of F in the same ratio?

I, II, and III

C2H4 + H2 = C2H6 C2H4 is reduced by H2 in the presence of a solid platinum catalyst, as represented by the equation above. Factors that could affect the rate of the reaction include which of the following? I. Changes in the partial pressure of H2. II. Changes in the particle size of the platinum catalyst. III. Changes in the temp of the reaction system

2.00 mol

C3H8 + 5O2 = 3CO2 + 4H2O In the reaction represented above, what is the total number of moles of reactants consumed when 1.00 mole of CO2 is produced?

-75.8 kJ mol-1

CH4(g) + 2O2(g) = CO2(g) + 2H2O(l) Hrxn= -889.1kJmol-1 Hf H2O(l) = -285.8 kJ mol-1 Hf CO2(g) = -393.3 kJ mol-1 What is the standard heat of formation of methane as calculated from the data above?

decreasing the temperature

CuO(s) + H2(g) = Cu(s) + H2O (g) H<0 The substances in the equation above are at equilibrium at pressure and temperature. The equilibrium can be shifted to favor the products by

F2 < HCl < HF

F2, HCl, and HF is order of increasing boiling point

100 mL volumetric flask

For an experiment, a student needs 100.0mL of a .4220M NaCl. If the student starts w/ NaCl and distilled water, which of the following pieces of lab glassware should the student use to prepare the solution w/ the greatest accuracy?

A

Gases generated in a chemical reaction are sometimes collected by the displacement of water. Which of the following gases can be quantitatively collected by this method? A) H2 B) CO2 C) HCl D) SO2 E) NH3

20 g

H2 + F2 = 2HF In the reaction represented above, what mass of HF is produced by the reaction of 3.0 x 10^23 molecules of H2 w/ excess F2?

CO3 2- (aq)

HSO4 + CO3 = SO4 + HCO3 The reaction represented above is observed to proceed spontaneously to the right in aqueous solution. In this system the strongest base is

B

In which flask do the molecules have the greatest average speed? A) T= 30C; P= 1atm B) T= 50C; P= 0.5atm C) T= 40C; P= 2atm D) T= 50C; P= 1atm E) T= 40C; P= 0.5atm

SiCl4(l)

London (dispersion) forces are the only type of intermolecular forces in what pure liquid?

the rate of reaction increases

Rate= k[H3AsO4] [I-] [H3O+] According to the rate law for the reaction, an increase in the concentration of the hydronium ion has what effect on the reaction at 25C?

1

The experimental rate law for the reaction at 25C is Rate= k[H3AsO4] [I-] [H3O+] What is the order of the reaction w/ respect to I-?

B

The reaction between a Bronsted-Lowry acid and a Bronsted-Lowry base A) 2C6H6 + 15O2 = 12 CO2 + 6H2O B) C2H3O2 + H3O = HC2H3O2 + H2O C) 4H + 4CO + O2 + 24NH3 = 4CO(NH3)6 + 2H2O D) CaCO3 = CaO + CO2 E) 2H2O2 = O2 + 2H2O

E

The reaction in which a single species is both oxidized and reduced A) 2C6H6 + 15O2 = 12 CO2 + 6H2O B) C2H3O2 + H3O = HC2H3O2 + H2O C) 4H + 4CO + O2 + 24NH3 = 4CO(NH3)6 + 2H2O D) CaCO3 = CaO + CO2 E) 2H2O2 = O2 + 2H2O

C

Which flask contains the sample w/ the greatest density? A) T= 30C; P= 1atm B) T= 50C; P= 0.5atm C) T= 40C; P= 2atm D) T= 50C; P= 1atm E) T= 40C; P= 0.5atm

B

Which flask contains the smallest number of moles of gas? A) T= 30C; P= 1atm B) T= 50C; P= 0.5atm C) T= 40C; P= 2atm D) T= 50C; P= 1atm E) T= 40C; P= 0.5atm

N

Which of the following elements has the largest first ionization energy? A) Li B) Be C) B D) C E) N

true

X(g) + Y(g) = Z(g) true/false for the chemical system represented above when the system has reached a state of equilibrium at constant temperature and pressure: the forward and reverse reactions occur at the same rate.

Y < Z < X

X: CH3CHOHCH2OH Y: CH3CH2Ch2CH3 Z: CH3CH2CHOHCH3 Considering the structures of the three compounds, X, Y, and Z, shown above, the ranking of their solubility in water from least to greatest is what?

NaNO3

a 0.1-molar aqueous solution of what is neutral?

.160 M

a 20.0-mL sample of .200 M K2CO3 solution is added to 30.0 mL of .400 M Ba(NO3)2 solution. Barium carbonate precipitates. the concentration of barium ion, Ba^+2, in solution after reaction is

C4H6

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?

HCO3- and CO3^-2

a Bronsted-Lowry acid-base pair

vapor pressure of the water

a compound is heated to produce a gas whose molar mass is to be determined. the gas is collected by displacing water in a water-filled flask inverted in a trough of water. what is necessary to calculate the molar mass of the gas but does not need to be measured during the experiment?

2.0 atm

a sample of gas has a volume of 1.0L at 300 K and 2.0 atm. if the volume and the absolute temperature are both doubles, what is the final pressure of the sample?

NH4+

a solution containing what ions will give off a pungent odor when added dropwise to warm NaOH(aq)

42.8 grams of KIO3 and add H2O until the final homogeneous solution has a volume of 2 L

a student wishes to prepare 2.00 liters of .100 M KIO3. the proper procedure is to weigh out

vapor pressure

as intermolecular forces become stronger for pure liquids, what tends to decrease?

0.77

at 20C, the vapor pressure of toluene is 22 mm Hg and that of benzene is 75 mm Hg. an ideal solution, equimolar in toluene and benzene, is prepared. at 20C, what is the mole fraction of benzene in the vapor in equilibrium w/ this solution?

D

based on periodic trends, which of the following atoms has the largest atomic radius? A) K B) Ga C) Br D) Cs E) Te

NH4+

cannot act as both a Bronsted-Lowry acid and a Bronsted-Lowry base

H2O2 < O3 < O2

compounds listed correctly in order of increasing strength of their oxygen-to-oxygen bonds

Cu2O

contains an element in a +1 oxidation state

HNO3 < NaNO3 < Na2CO3 < NaOH

correctly ranked substances in order of increasing pH of the solution they produce

false

each of three flexible vessels contains a gas at the same temperature and pressure. the first contains 2.0 g of H2(g), the second contains 32.0 g of O2(g), and the third contains 44.0 g of CO2(g). true/false: the average speed of the molecules in each of the vessels is the same.

P H2 < P N2 < P Ar

equal numbers of moles of H2(g), Ar(g), and N2(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, what is true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?

BH3

has a central atom w/ less than an octet of electrons

NH3

has a trigonal-pyramidal molecular geometry

CO3^-2

has polar bonds but a zero dipole moment

H2O

has two lone pairs of electrons

1.0 x 10^-4

if a 1.0M solution of HA, a weak acid, has a pH of 2.0, then the value of Ka, the acid-dissociation constant, for HA is closest to

4%

if the acid dissociation constant, Ka, for an acid HA is 8 x 10^-4 at 25C, what percent of the acid is dissociated in a .50M solution of HA at 25C?

AlF3

in the formation of 1.0 mole of crystalline solids from gaseous ions, the most energy is released by

BH3

is predicted to have the largest bond angle

I2

longest bond length

catalyst

lowers the activation energy by changing the mechanism of the reaction

critical temperature

lowest temperature above which a substance cannot be liquefied at any applied pressure

CCl4

molecule that contains polar covalent bonds but is a nonpolar molecule

collisions of the gas molecules w/ the walls of the container

most directly responsible for the pressure of a gas in a sealed container

D

on the basis of trends in the periodic table, an atom of which of the following elements is predicted to have the lowest first ionization energy? A) Ar B) Cl C) K D) Rb E) I

Br

one atom of an element w/ the smallest radius

B - F

one of the most polar single covalent bonds

S

oxides of what element is responsible for acid rain?

2NO2 = N2O4

reaction mixture at equilibrium that would reduce the volume of the container at constant temp and cause the equilibrium to shift toward the products

a network solid w/ covalent bonding

solid silicon dioxide, SiO2, is

I-

species that cannot function as an oxidizing agent?

46.0 g/mol

the density of an unknown gas is 4.20 grams per liter at 3.00 atm and 127C. What is the molar mass of this gas?

trigonal planar

the geometry of the SO3 molecule is best described as

density of the solution

the molality of the glucose in a 1.0M glucose solution can be obtained by using what?

+4

the oxidation number of silicon in the compound Na2Mg2Si6O15 is

11

the pH of .1M ammonia is approximately

HF molecules tend to form hydrogen bonds

the relatively high boiling point of HF can be correctly explained by what?

true

true/false: the halide ions are larger than their respective halogen atoms.

.10 M potassium sulfate, K2SO4

what aqueous solutions has the highest boiling point?

NH3

what compound is amphoteric?

Zn

what element is most likely to be in the +2 oxidation state in its compounds?

K

what element is never found pure in Earth's crust?

xenon

what gas deviates more from ideal gas behavior because of attractive forces between atoms

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

what is a correct interpretation of the results of Rutherford's experiments in which gold atoms were bombarded w/ alpha particles?

SO2

what is involved in the environmental problem known as acid rain?

+6

what is the oxidation number of Cr in CrO4^-2

.250 mole

what number of moles of O2 is needed to produce 14.2 grams of P4O10 from P?

Br2

what pure substance is a reddish-brown liquid at 298K and 1atm?

H2O + HSO4- = H2SO4 + OH-

what reaction doesn't proceed significantly to the right in aqueous solutions

H3O+ ions

what species are in the greatest concentration in a .100 M solution of H2SO4 in water?

n=6 to n=4

what transition of an electron in a hydrogen atom will emit a photon that has the highest frequency?

4.5 M

when 70 mL of 3.0 M Na2CO3 is added to 30 mL of 1.0 M NaHCO3, the resulting concentration of Na+ is

E

which of the following indicators is most appropriate for determining the equivalence point in the titration of a weak acid w/ a strong base? A) Thymol blue 1.2-2.8 B) Methyl orange 3.1-4.4 C) Methyl red 4.4-6.2 D) Bromcresol purple 5.2-6.8 E) m-cresol purple 7.6-9.2

2

...LiHCO3 (aq) + ...H2SO4(aq) = ...Li2SO4(aq) + ...H2O(l) + ...CO2(aq) When the equation above is balenced and the coefficients are reduced to lowest whole-number terms, what is the coefficient of H2O(l)?

2

...MnO4-(aq) + ...NO2-(aq) + ...H2O(l) = ...MnO2 + ...NO3-(aq) + ...OH-(aq) when the redox equation shown above is balanced by using coefficients reduced to lowest whole numbers, the coefficient for MnO4- is