Quimica Inorganica Spellbook Flashcards

1
Q

What type of bond is found in carbon monoxide?

A) Nonpolar single bond

B) Polar single bond

C) Polar double bond

D) Polar triple bond

A

(D) The Lewis Dot Structure for carbon monoxide has a triple bond that is polar, with the oxygen being slightly negative due to its higher electronegativity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The Ksp value for silver iodide, AgI, is 4 x 10-16. What is the molar solubilitry of silver iodide?

A) 2 x 10-8

B) 2 x 10-16

C) 8 x 10-16

D) 8 x 10-32

A

(A) Because the concentrations of silver and iodide ions are equal, the expression to be solved is 4 x 10-16 = x2 where x = 2 x 10-8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If a sample of gas is heated from 10°C to 20°C, the volume of the gas will:

A) increase slightly from the original volume

B) be double the original volume

C) decrease slightly from the original volume

D) be half of the original volume

A

(A) In order to qualitatively determine the effects of temperature on a gas, the temperature must be in Kelvin, so the change in temperature is from 283 K to 293 K, or about 3%.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which of these elements have the highest electronegativity?

A) Sodium

B) Silicon

C) Sulfur

D) Selenium

A

(C) High electronegativities are features of nonmetallic elements, with the highest electronegativity value assigned to fluorine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What type of reaction is taking place in the precipitate formations?

A) Hydrolysis reaction

B) Single replacement reaction

C) Synthesis reaction

D) Double replacement reaction

A

(D) Each precipitate reaction is a double replacement (or double displacement) reaction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The solubility product constant for silver chloride is 4 x 10-10. What is the solubility of silver chloride in a solution of 0.1 M NaCl?

A) 2 x 10-5

B) 4 x 10-5

C) 4 x 10-9

D) 4 x 10-11

A

(C) This is an applicaiton of the common ion effect. Because the concentration of the Cl- ion is 0.1 M, the addition of a very small amount of the Cl- ion from AgCl is small enough to be ignored, so 4 x 10-10 = 0.1x where x is going to be equal to 4 x 10-9 M.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ice at zero degrees Celsius is palced in water at zero degrees Celsius. Which of the following would occur?

A) The ice melts

B) All of the ice melts but part of the water also freezes

C) None of the ice melts and none of the water freezes

D) Some of the ice melts and some of the water freezes

A

(C) If the temperature is the same, no heat flow.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pure bromine has a density of 3.2 g/cm3 at room temperature. What is the molarity of pure bromine?

A

20.0 M. At room temperature, there are (3.2 g/cm3 x 1000 cm3/L) 3200 g of bromine and so dividing it by 160 (Br2 = 80 + 80 = 160) would make a molarity of 20.0 M.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

When 20.0 mL of a 0.1 M solution of potassium hypochlorite is added to 10.0 mL of a solution of 0.1 M solution of hypochlorous acid with a few drops of phenol red added to it, what color change, if any, would be observed?

(Hint: Phenol Red is yellow in acidic conditions and red in basic conditions)

A

Adding the basic salt KClO to a weak acid would increase the pH enough for it to become basic. So it would turn from yellow to red.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The equation below is unbalanced:

ClO3-1 + Mn+2 -> Cl2 + MnO4-1

What happens to the chlorine atoms in the process of the equation?

A

Chlorine atoms are reduced and each chlorine atom gains 5 electrons.

Oxidation Number of chlorine in the reactants: x - 6 = -1

x = 5

Oxidation Number of chlroine in the products: x = 0

x = 0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Consider the following excerpt from a reaction:

H2SO4(aq) -> 2CO2

What volume of 4.0 M sulfuric acid is needed to produce 44.8 L of carbon dioxide gas at STP?

A

250 mL. To have a 4.0 M concentration, sulfuric acid needs to have 1 mole / 0.25 L. Seeing as one mole would create 2 moles of carbon dioxide (which is 44.8 L at STP), we need 250 mL of sulfuric acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The heat of combustion of tristerain (molar mass = 926) is 37,000 kj/mole. By how many degrees Celsius could 1000 grams of water be heated using the heat produced by the combustion of one gram of tristearin? The specific heat capacity of water is 4.181 J/g ºC

A

The temperature change of water could be found using ΔH = mCΔT. 37,000 J = (926 g)(4.184 J/gºC)(ΔT)

ΔT = 9.5 degrees.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The compound arsenic trichloride obeys the octet rule. What is the molecular geometry and polarity of phosphorous trichloride?

A

It is trigonal pyramidal in shape and it is polar.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which of the following pairs of 0.1 M solutions will produce a precipitate?

A) Silver nitrate and lead(II) chloride

B) Lead(II) nitrate and nitric acid

C) sodium bromide and calcium chloride

D) potassium nitrate and mercury(II) acetate

A

Silver chloride is an insoluble solid. So: (A)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Given the equilibrium constants for the synthesis of hydrogen iodide (10-1) and hydrogen chloride (1016), the rate of synthesis of HCl compared to the rate of formation of HI at the same temperature is:

A

Reaction rates cannot be determined from equilibrium constants or other thermodynamic data.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Compared to aqueous HCl, the acidity of aqueous HI is:

A

HI is a stronger acid because I- ions are larger than Cl- ions, making HI bonds weaker than HCl bonds so HI more readily dissociates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When the boiling points of the silver nitrate [AgNO3] and lead nitrate [Pb(NO3)2] solutions are compared, what results are obtained if both solutions are 0.1 M?

A

Boiling point elevation depends on the number of moles dissolved particles. Because the comparison is between equimolar solutions of lead nitrate and silver nitrate and because lead nitrate dissociates into three ions while silver nitrate dissociates into two ions, lead nitrate will have a higher boiling point.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When a piece of magnesium metal is placed in a solution of copper(II) nitrate, what occurs?

A

Because magnesium is more reactive than copper, the magneisum metal will be oxidized to magnesium ion and the copper ion is reduced to copper metal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When lead (II) reacts with sulfuric acid, what is the most likely aqueous product?

A

PbSO4 because SO4 has a -2 charge and Pb has a +2 charge.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What prediction can be made about the miscibility of hexane and toluene?

A

Hexane and toluene will be miscible in each other because they can have London dispersion forces to facilitate mixing. Both are nonpolar, which rules out hydrogen bonding and dipole interactions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Sulfur atoms can sometimes form compouns with more than four pairs of bonding electrons. Which orbitals are responsible for allowing sulfur atoms to do this?

A) 2p

B) 2d

C) 3d

D) 3p

A

(C) Expanded octets involve d orbitals. The second energy level has no d orbitals, so it cannot be correct.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How do the rates of diffusion of Ar (molar mass = 40) and Br2 (molar mass = 160) compare assuming both gases are at the same temperature and pressure?

A

Use Graham’s law, the rate of diffusion of gases are inversely proportional to the square root of their molar masses: v1/v2 = sqrt(m2/m1) so: v1/v2 = sqrt(160/40): Ar will diffuse twice as fast as Bromine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Water can be a Bronsted Lowry base because it can:

A

Accept a proton.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Zn + HCl → ZnCl2 + H2
Consider the above unbalanced reaction. How many mL of a 4 M solution of HCl would be required to produce 22.4 L of H2 gas at STP?

A

Since the reaction is unbalanced, we should balance it first, so we see

Zn + 2HCl → ZnCl2 + H2
which means that we need 2 moles of HCl for each mole of H2 we want to produce. 22.4 L of gas at STP is 1 mole, so we need 2 moles of HCl to react. In a 4 M solution, 2 moles would be found in 1/2 L or 500 mL since the solution has 4 moles per liter and therefore 2 moles per half-liter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How many moles of Na+ ions were are there in the initial Na2SO4 solution used in this reaction:

Initially, 15.0 mL of 0.300 M Pb(NO3)2 was mixed with 15.0 mL of 0.300 M Na2SO4. All the Pb(NO3)a reacted to form Compound A, a white precipitate. Compound A was removed by filtration.

A
  1. 009 moles. The initial solution in this reaction is 15 mL of 0.300 M Na2SO4:
    (15. 0 mL)(1 L)(0.300 mol Na2SO4)(2 mol Na2+‑) / (1000 mL) (1 L Na2SO4)(1 mol Na2SO4) = 0.009 moles.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Pb(OH)2(s) is slightly soluble in water. How would the amount of Pb(OH)2(s) that normally dissolves in 1 L of water be affected if the pH were 9.0?

A) Less would dissolve

B) The same amount would dissolve

C) More would dissolve

D) There is no way to predict the effect of the change in pH of the water

A

(A). Less would dissolve. At pH 9, the concentration of OH- is greater than the concentration of OH- at pH 7.Pb(OH)s à Pb2+ + 2 OH- and so according to Le Chatelier’s Principle, with more products available, the reaction would shift toward the reactants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The ability of NH3 to form coordination compounds with transition metal ions can best be accounted for by the fact that NH3:

A) acts as an electron pair donor

B) is capable of hydrogen bonding

C) is a weak base in aqueous solution

D) contains N with a -3 oxidation number

A

(A) In a coordination compound between ammonia and a transition metal ion, a covalent bond is formed between the nitrogen atom of ammonia and the metal ion. The formation of such a bond is often called a Lewis acid-base reaction. The metal ion is deficient in electrons, and ammonia has a pair of electrons available for bonding. Therefore, both electrons that compromise the new covalent bond come from ammonia.

31
Q

An aqueous solution of a salt made by mixing which of the following acids and bases displays the lowest pH?

A) strong acid, weak base

B) strong acid, strong base

C) weak acid, weak base

D) weak acid, strong base

A

(A) Consider each of the interactions:

Strong acid, weak base

pH < 7

Strong acid, strong base

pH = 7

Weak acid, weak base

pH = 7

Weak acid, strong base

pH > 7

32
Q

At the stoichiometric (equivalence) point in a titration of benzoic acid with NaOH, the pH is:

A) < 4

B) > 4 and < 7

C) = 7

D) > 7

A

(D) The pH at the equivalence point in any titration is the pH of the salt solution formed. At the equivalence point, the solution contains sodium benzoate and water. Benzoic acid is a weak acid, so it must have a pH greater than 7

33
Q

If a student did NOT remove all the moisture from the KHP before the titration with NaOH to standardize the NaOH solution, then the molarity determined for the NaOH would be:

a) too high because the actual number of moles of KHP titrated would be less than the number used in the calculations
b) too low because the actual number of moles of KHP titrated would be more than the number used in the calculations
c) too low because the actual number of moles of KHP titrated would be less than the number used in the calculations
d) unaffected because the weighed KHP was dissolved in water, making any moisture in the sample unimportant

A

(A) If a student weighs a sample of KHP that contains moisture, the measurement will include the mass of KHP and water and will be larger than the mass of KHP alone. This will make the number of moles of KHP too high and since the number of moles of NaOH equals the number of moles of KHP at the equivalence point, the number of moles of NaOH will also be too high.

34
Q

Crystals precipitate when each of the following compounds is added to a saturated of KNO3(aq) EXCEPT:

A) NH4NO3

B) Ca(NO3)2

C) NH4Cl

D) KCl

A

(C) A saturated solution of KNO3 contains the maximum number of K+ and NO3 ions the solution can hold without precipitating solid KNO3. The addition of any salt that adds either of these two ions will cause KNO3(s) to form.

35
Q

Suppose that CH4 reacts completely with O2 to form CO2 and H2O with a total pressure of 1.2 torr. What is the partial pressure of H2O?

A) 0.4 torr

B) 0.6 torr

C) 0.8 torr

D) 1.2 torr

A

(C)The balanced equation for the complete combustion of CH4 is:

CH4 + 2O2 –> CO2 + 2H2O

The pressure of the gaseous products is 1.2 torr. For every three product molecules, two are water. Therefore, the partial pressure of water is 2/3 of the total pressure. 2/3 of 1.2 is 0.8 torr.

36
Q

Electrons in which of the following orbitals of Ti can form bonds with a substance X?

A) 2s

B) 3d

C) 4p

D) 5f

A

(B) Titanium, as a transition element, would be expected to interact via its valence shell 3d electrons. The ground state of Ti has the electron configuration [Ar] 3d2 4s2. In the ground state, there are no 4p or 5f electrons. While Ti does have 2s electrons, they are in the core, much lower in energy than the valence electrons. They would not be expected to interact with neighboring atoms.

37
Q

Attached is a phase diagram for water. As the pressure applied to a sample of water at -0.1 degrees Celsius is increased from 1.0 torr to 200 atm at constant pressure, the:

A) vapor will become a solid then a liquid

B) vapor will become a liquid and then a solid

C) vapor will become and remain a solid

D) solid will become a liquid

A

(A) The sample will start off as a vapor since it is between the dotted lines at the 1 torr mark. 200 atm is about 152k torr, so at constant temperature, the vapor will turn into solid (deposition) and then it will eventually reach liquid.

38
Q

When a strip of Cu is placed into H2O, no change is observed. However, when a strip of Cu is placed into a solution of HNO3, a gas evolves. What is the most likely identity of the gas?

A) NO

B) CO2

C) H2

D) O3

A

(A) Nitrogen monoxide is one gas evolved when copper metal is placed in a nitric acid solution. This is a red-ox reaction. Copper is oxidized and nitrogen is reduced. Nitric acid is an oxidizing agent. While the formation of H2 is plausible, it is not observed because the much more electronegative nitrogen undergoes reduction more readily than does hydrogen.

39
Q

The pKa for the dissociation of H2PO4- to HPO42- is 6.7. What is the initial ratio of [HPO42-]:[H2PO4-] in a buffer solution with pH equal to 8.7?

A) 1:1

B) 2:1

C) 100:1

D) 200:1

A

(C) Use the Henderson Hasselbach equation: pH = pKa + log([base]/[acid] which is the same as:

8.7 = 6.7+ log(HPO42/ H2PO4-). 2 = log(HPO42/ H2PO4-). Thus, the ratio between the two entities is 102 or 100:1.

40
Q

n CDP ⇄ (CP)n + n HPO42- with PNP and Mg2+ as catalysts

According to this equation, the concentration of the polymer (CP) with respect to [HPO42-] is:

A) n[HPO42-]

B) n2[HPO42-]

C) (1/n) [HPO42-]

D) (1/n2) [HPO42-]

A

(C) According to the balanced coefficients in Equation 1, each time one molecule of the polymer is formed, there are n hydrogen phosphate ions produced. Thus, the concentration of the polymer must be 1/n times the concentration of HPO42-

41
Q

From reactions 3-5, what can be determined about the relative concentrations of CFC’s (F3CCl) and O2?

A) One equivalent of CFC is required to produce one equivalent of O2

B) One equivalent of CFC is required to produce two equivalents of O2

C) A catalytic amount of CFC can produce much O2

D) The CFC is produced by a catalytic amount of O2

A

(C) After the initial step of breaking the bond in the chlorofluorocarbon, the radicals are recycled. In other words, these two species act as catalysts: they react with the substrate (O3 and O) and are re-formed. The re-formed radical can participate in another cycle of the reactions 4 and 5, thus a small amount of CFC can produce much O2 by catalyzing the decomposition of ozone.

42
Q

Which of the following electron configurations depicts an atom in an excited state?

A) 1s22s22p63s23p64s1
B) 1s22s22p63s23p64s23d1
C) 1s22s22p63s23p64s13d1
D) 1s22s22p63s23p5

A

(C) An atom in an excited state should have filled its orbitals in order and have one electron in a higher state than it should be. For (A), the orbitals have filled normally, as well as in (B) and (D). In (C), we see that the 4s only has 1 electron in it while the 3d has 1 electron in it. Normally, the 4s would have 2 electrons before the 3d gained one.

43
Q

Which of the following aqueous solutions would not produce a pH buffer solution?

I. A strong acid and a strong base
II. A strong acid and a weak acid
III. A strong acid and its conjugate base

A) III only
B) I and II only
C) II and III only
D) I, II, and III

A

(D) Buffer solutions are created with weak acids and their conjugate bases or with weak bases and their conjugate acids. Strong acids and strong bases will produce a salt and water (usually) which will not act as pH buffers. Strong acids and weak acids will simply produce an acidic solution which will still not act as buffers. Strong acids and their conjugate bases will not work either since a weak acid is needed. Therefore, none will produce a buffer solution and the answer is (D).

44
Q

Which of the following has the most positive oxidation state of carbon?

A) C2H6
B) CHCl3
C) CH4
D) C2H2

A

(B) The oxidation states of carbon are, respectively: -3, +2, -4, and -1. Thus (B) is the correct answer.

45
Q

Which of the following has the greatest first ionization energy?

A) Na
B) Mg
C) K
D) Ca

A

(B) The ionization energy (IE) is the energy required to remove an electron from an atom. On the periodic table, IE generally increases going from bottom to top and from left to right. Thus Mg and Ca both have higher ionization energies than Na and K, and Mg has a higher ionization energy than Ca.

46
Q

A particular liquid is brought up to boiling point. Some solute (for instance sodium chloride) is added to the solution. Which of the following would hold true?

A) The solution will stop boiling
B) The solution will boil more vigorously
C) Vapor pressure of the solution will decrease
D) Temperature will fall

A

(C) When solute is added to the liquid, it gets in the way of molecules at the surface, which are trying to escape out into the atmosphere. This results in a decreased capacity for the molecules of liquid to escape, thus vapor pressure of the solution will decrease. (A) is incorrect because we cannot be sure that the entire solution will desist boiling. This could definitely happen if a case of salt was added to a pot of boiling water, but it might not be the case for different amounts. (B) is incorrect, and we would not expect temperature to fall thus (D) is incorrect as well. Thus, (C) is the correct answer.

47
Q

What is the Lewis structure for hydrazine?

A

A nitrogen atom has 3 single electrons and 1 lone pair. Hydrogen has one electron. So nitrogen has three bonds and one lone pair.

48
Q

When electrons oscillate through the equilibrium point (B) and move to a maximum point (C), it is because of:

A) the momentum gathered as they moved from the other extreme, point A

B) Coulomb forces pulling on the electron sea

C) magnetic forces of attraction between the positive ions and the electron sea

D) the large potential energy at point B

A

[A] as electrons move from A to B, they convert potential energy to kinetic energy and gain velocity and hence momentum. This momentum is enough to allow the electrons to go from B to C.

49
Q

SiCl3H has a normal boiling point of 33ºC. What are the predominant forces between SiCl3H molecules?

A) ionic bonds

B) covalent bonds

C) hydrogen bonds

D) van der Waals forces

A

[D] Van der Waals forces are weak intermolecular attractive forces. They have relatively low boiling points because the forces are not strong.

50
Q

A gas that occupies 10 L at 1 atm and 25ºC will occupy what volume at 500 atm and 25ºC?

A) exactly 0.020 L

B) somewhat more than 0.02 L because the space occupied by the individual gas molecules

C) somewhat more than 0.02 L because of the repulsions between the individual gas molecules

D) somewhat more than 0.02 L because of the increased number of collisions with the sides of the container

A

[B] the ideal law makes the assumption that molecules have no volume. The assumption is adequate when the gas is at 1 atm, but when the pressure is increased to 500 atm the volume of the gas molecules is no longer negligible.

51
Q

The rate of NO2 + OCl is slower than NO2 + HOCl in forming NO3 because the formation of HOCl by the protonation of oxygen:

a) reduces the electronic repulsion forces between the reactants
b) increases the electronic repulsion forces between the reactants
c) increases the electronic repulsion forces between the nitrogen atom and oxygen atom being transferred
d) reduces the electronic attraction forces between the chlorine atom and the oxygen atom that is being transferred

A

[A] two anions will experience electrostatic repulsion due to their negative charge. Protonation of the oxygen would generate an electrically neutral species and the repulsion forces would be reduced

52
Q

The energy, E, of a hydrogen atom with its electron in the nth shell of a hydrogen atom is given by E = -C/n2 where n = 1,2,3…and C is a positive constant. If an electron goes from the n = 2 shell to the n = 3 shell.

A) a photon is emitted

B) an electron is emitted

C)an electron is absorbed

D) the energy of the atom is increased

A

[D] The energy of an electron in orbit n = 3 is less negative or greater than the energy in orbit n = 2. Thus energy is required to make the transition from n = 2 to n = 3 and the atom gains energy.

53
Q

Ba2+(aq) is an ion that is very toxic to mammals when taken internally. Which of the following compounds, mixed in water, would be the safest if accidentally swallowed?

A) BaSO4, Ksp = 1.1 x 10-10

B) BaCO3, Ksp = 8.1 x 10-9

C) BaSO3, Ksp = 8.0 x 10-7

D) BaF2, Ksp = 1.7 x 10-6

A

[A] The lower the Ksp, the lower the concentrations of cation and anion in aqueous solution and the lower the solubility of the compound in water. If mixed with water and accidentally swallowed, the Ba salt with the lowest value of Ksp would be the safest

54
Q

When aqueous solutions of the various anions and cations were mixed, precipitates formed because:

A) few aqueous solutions can contain more than one cation or anion

B) the anions precipitated as solid metals

C) the solubility of cations were decreased by the other cations

D) the solubility product of a compound was exceeded

A

[D] The amount of substance that will dissolve in water is described by the Ksp. If the amount of compound present is in excess of the Ksp, then a precipitate would form to maintain the Ksp

55
Q

Why would temperature fall as a balloon rises?

A) The work done on the gas by the water pressure decreases its temperature

B) The work done by the gas in expanding decreases its internal energy

C) The balloon and water exchange heat, increasing the temperature of the gas

D) The compression of the gas decreases its temperature

A

[B] As the balloon rises, temperature falls so it must decrease its internal energy as it decreases its pressure.

56
Q

A sparingly soluble metal hydroxide, M(OH)2 has a molar solubility of S mol/L at 25ºC. Its Ksp value is:

A) S2

B) 2S2

C) 2S3

D) 4S3

A

[D] Ksp = [M][OH-]2 so [S][2S]2 is equal to 4S3

57
Q

When 2I- and S2O82- interact, they form I2 and 2SO42-. Students use starch as an indicator to detect the excess I2 that accumulated as S2O32- was used up. The solution turned dark blue when starch and I2 combined. So, students prepared two solutions:

Solution A contained KI and Na2S2O3

Solution B contained (NH4)2S2O8 and starch.

The results of the experiment would most likely NOT be affected if the students had added excess:

A) KI to Solution A

B) Na2S2O3 to Solution A

C) (NH4)S2O8 to Solution B

D) Starch to solution B

A

[D] Starch is not a participant in any of the reactions, acting only as an indicator of excess I2

58
Q

Which of the following statements is consistent with the incorrect conclusion that HCl is an ionic compound?

A) It is a gas at room temperature

B) A 1 M solution freezes below 0ºC

C) A 1 M solution conducts electricity

D) It is composed of two nonmetals

A

[C] Ionic compounds conduct electricity

59
Q

With respect to bonding and electrical conductivity, respectively, sulfur hexafluoride SF6(g) would be described as:

A) covalent and a nonconductor

B) ionic and a nonconductor

C) covalent and conductor

D) ionic and conductor

A

[A] Covalent compounds are comprised of nonmetallic elements whereas binary ionic compounds are made up of a metal and a nonmetal. Covalent compounds do not conduct electricity.

60
Q

At which electrode is the aluminum produced in this reaction

2Al2O3 -> 4Al + 3O2

in a galvanic cell and in an electrolytic cell?

A) At the anode in both cells

B) At the cathode in both cells

C) At the anode in the galvanic cell and cathode in the electrolytic cell

D) At the cathode in the galvanic cell and anode in the electrolytic cell

A

[B] Reduction of the Al3+ to form Al occurs at the cathode in both a galvanic and electrolytic cell.

61
Q

In the reaction shown in this equation:

Al(OH)3 + NaOH -> Na[Al(OH)4]

Al(OH)3 acts as what kind of acid or base?

A) Lewis acid

B) Lewis base

C) Bronsted acid

D) Bronsted base

A

[A] The aluminum accepts an electron pair from the OH- of NaOH and is therefore acting as a Lewis acid.

62
Q

What is the electron configuration of chlorine in NaCl? (Chlorine has 17 protons)

A) 1s22s22p63s23p4

B) 1s22s22p63s23p5

C) 1s22s22p63s23p6

D) 1s22s22p63s23p44s2

A

[B] In NaCl, chlorine exists as the chloride ion. A chloride ion has 18 electrons with the electron configuration. 1s22s22p63s23p6

63
Q

Which compound evaporates the fastest?

A) MTBE (Vapor pressure = 25 torr)

B) ETOH (Vapor pressure = 58 torr)

C) ETBE (Vapor pressure = 20 torr)

D) TAME (Vapor pressure = 15 torr)

A

[B] The greater the vapor pressure, the greater the rate of evaporation.

64
Q

The disposal of waste chemical is a common laboratory problem. An experiment to determine the copper content of a penny produces a waste mixture at pH 9 containing copper and zinc in the form of soluble complex ions of ammonia and solid hydroxides.

Given this equation:

Cu(NH3)42+(aq) <-> Cu2+(aq) + 4NH3

The oxidation state of copper in going from the penny to the waste mixture changes from:

A) 0 to +2

B) 0 to +1

C) +1 to 0

D) +2 to 0

A

[A] Copper metal in the penny has an oxidation state of 0. The waste mixture, Cu(NH3)42+ has an oxidation state of +2.

65
Q

What is the formula for zinc(II) sulfide?

A) Zn2S

B) ZnS

C) ZnS2

D) Zn2S3

A

[B] Zinc has a charge of +2 and Sulfide has a charge of –2

66
Q

The literature value for the Ksp shown in this reaction

Zn(OH)2(s) <-> Zn2+ + 2OH-

is determined by the value of:

A) [Zn2+][OH-]2 in a saturated solution

B) [Zn2+][OH-] in an unsaturated solution

C) [Zn2+][OH-] in a saturated solution

D) [Zn2+][OH-]2 in an unsaturated solution

A

[A] The Ksp of a salt is the equilibrium constant for the dissolution of that salt. It describes a saturated solution in which the aqueous ions are in equilibrium with the solid.

67
Q

After an acid treatment, metals exist as aqueous ions in an acidic solution from which they can be precipitated as insoluble sulfides by the addition of sodium sulfide. The solubility product constants for copper(II) and zinc(II) sulfides are 6.7 x 10-42 and 1 x 10-27,respectively.

Is the procedure more effective for zinc or copper?

A) Zinc, because its Ksp > Ksp of copper sulfide

B) Zinc, because its Ksp < Ksp of copper sulfide

C) Copper, because its Ksp > Ksp of zinc sulfide

D) Copper, because its Ksp < Ksp of zinc sulfide

A

[D] Copper(II) Sulfide would be less soluble with its lower Ksp value, and therefore the treatment would be more effective.

68
Q

The structure and bonding of diamond, which is formed from graphite at extreme pressures, should be similar to that of elemental:

A) aluminum and gallium

B) silicon and germanium

C) phosphorous and arsenic

D) sulfur and selenium

A

[B] At extreme pressures, an elemental solid assumes the structure and bonding characteristics of a heavier element in the same column of the periodic table. The structure and bonding of diamond, which is a form of carbon, would be like most other elements in its group which contains silicon and germanium.

69
Q

What bonding accounts for the expected increase in energy density of solid nitrogen as compared to methanol?

A) solid nitrogen contains covalent and ionic bonds; methanol contains only weak ionic bonds

B) solid nitrogen contains covalent and ionic bonds; methanol has covalent bonds within each molecule and weak van der Waal’s interactions between molecules

C) solid nitrogen contains only covalent bonds; methanol contains only weak ionic bonds

D) solid nitrogen contains only covalent bonds; methanol has covalent bonds within each molecule and weak intermolecular interactions

A

[D] Solid nitrogen contains only covalent bonds. Methanol contains only covalent bonds, but it can do intermolecular hydrogen bonding because of the –OH group

70
Q

What are the oxidizing and reducing agents, respectively, in the reaction below?

2HCl + H2O2 + MnO2 à O2 + MnCl2 + 2H2O

A) H2O2; HCl

B) H2O2; MnO2

C) MnO2; HCl

D) MnO2; H2O2

A

[D] In the reaction, Mn is reduced from +4 to +2; therefore, MnO2 is the oxidizing agent. O is oxidized from -1 to H2O2 to 0 in O2, therefore H2O2 is the reducing agent.

71
Q

The maximum mass of H2 that would be expected to form by the reaction of 6.54 g Zn with 50.0 mL of 0.1 M HCl is equal to which of the following?

A) 0.0025 g

B) 0.005 g

C) 0.1 g

D) 0.2

A

[B] The balanced reaction is: Zn(s) + 2HCl(aq) –> H2(g) + ZnCl2(aq). There is a limiting reagent question, so the number of moles of HCl is found by multiplying the volume in liters (0.05 L) by the concentration (0.1 mol / L) which is 0.005 moles HCl. The number of moles of zinc is 0.1 mol. So the limiting reagent is HCl. So: 0.005 mol HCl x 1 mol H2 / 2 mol HCl x 2 g H2 / 1 mol H2 = 0.005 g H2.

72
Q

What is the angular momentum number (l) for the orbital from which a Mg atom loses two electrons to form a Mg2+ ion

A) 0

B) 1

C) 2

D) 3

A

[A] The angular momentum quantum number dictates the shape of the orbital. It is the same as the number of angular nodes. When l = 0, the electron configuration is s. When l = 1, the electron configuration is p. When l = 2, the electron configuration is d. When l = 3, the electron configuration is f.

73
Q

The pressure inside a sealed 3-L tank containing 25 g of which product would be the highest at 300 K? (Assume no condensation)

A) CO2

B) H2O

C) N2

D) O2

A

[B] According to the Ideal Gas Law, pressure and moles of gas are directly proportional to each other. As one increases, so does the other. The gas sample that will exert the highest pressure is the same on that contains the most molecules or the most moles which is H2O

74
Q

The average bond energies in kJ/mol of the C-H, C-O, C-C, and O-N single bonds present in nitroglycerin are 413, 358, 347, and 201, respectively. Which single bond present in nitroglycerin is most likely the shortest?

A) C-H

B) C-O

C) C-C

D) O-N

A

[A] The highest bond energy has the lowest bond length