Title: Uncategorised Questions

Q: A supercritical fluid describes the physical state of a gas that will be converted to a liquid when the temperature is above the critical temp. and the pressure is increased.
- True (Refresh the definition of and the phase diagram for a supercritical fluid. Remember, a Supercritical Fluid (SF) describes the resulting physical state of a gas held at a temperature above its critical temperature, such that regardless of any increase in pressure the substance cannot be liquefied!)
- False (Correct. A Supercritical Fluid (SF) describes the resulting physical state of a gas held at a temperature above its critical temperature, such that regardless of any increase in pressure the substance cannot be liquefied!)
A: False

Q: Affinity chromatography uses the preparation of a particular stationary phase to target a specific solute.
- True (Correct. Affinity chromatography utilizes the specificity of a donor-ligand interaction for the target compound where the specific ligand is immobilized by covalent attachment (bonding) to the support material.)
- False (Refresh the definition and use of affinity chromatography. Remember, affinity chromatography is a special type of chromatography that is intrinsically designed to incorporate a specific donor-ligand interaction for the target compound. The specific ligand is immobilized by covalent attachment (bonding) to the support material.)
A: True

Q: Steric hindrance of the donor-ligand attachment is not a problem in Affinity chromatography.
- True (Refresh the interaction between the attached ligand and a target molecule. Remember, often a short-chain alkyl spacer is needed between the support material and the ligand to eliminate steric hindrance of the bonding attachment of the ligand to a bulky target molecule (such as a protein).)
- False (Correct. Often a short-chain alkyl spacer is needed between the support material and the ligand to eliminate steric hindrance of the bonding attachment of the ligand to a bulky target molecule (such as a protein).)
A: False

Q: Supercritical carbon dioxide is used commercially for the extraction of caffeine from water.
- True (Refresh the uses for a supercritical fluid. Supercritical CO_2 used as a "liquid" to extract from a solid not a liquid phase. US Patent 4820537 - Method for decaffeinating coffee with a supercritical fluid. A method of extracting caffeine from green coffee beans whereby an essentially caffeine-free supercritical fluid is continuously fed to one end of an extraction vessel containing green coffee beans and caffeine-laden supercritical fluid is continuously withdrawn from the opposite end.)
- False (Well done. Supercritical CO_2 used as a "liquid" to extract from a solid not a liquid phase. US Patent 4820537 - Method for decaffeinating coffee with a supercritical fluid. A method of extracting caffeine from green coffee beans whereby an essentially caffeine-free supercritical fluid is continuously fed to one end of an extraction vessel containing green coffee beans and caffeine-laden supercritical fluid is continuously withdrawn from the opposite end.)
A: False

Q: Silica gel is commonly used as the stationary phase in Thin Layer Chromatography for the analysis of non-polar compounds.
- True (Refresh polarity of stationary phases used in chromatography. Remember,Silica gel is apolar stationary phase as it contains terminal silanol groups = polar sites)
- False (Correct. Silica gel contains terminal silanol groups = polar sites)
A: False

Q: The ligand-substrate interaction in Affinity Chromatography can be weakened by adjusting the ionic strength of the eluent (mobile phase) so that the substrate can be eluted.
- True (Well done. That's right, the two main ways of weakening the ligand-substrate interaction in affinity chromatography is by changing the pH or ionic strength of the eluent so that the retained substrate can be eluted (washed) from the stationary phase.)
- False (Refresh the details of affinity chromatography. Remember, there are two main ways of weakening the ligand-substrate interaction in affinity chromatography by changing the pH or ionic strength of the eluent so that the retained substrate can be eluted (washed) from the stationary phase.)
A: True

Q: Large solute molecules are retained in the pores of the stationary phase and elute after small solute molecules in Molecular Exclusion Chromatography.
- True (Refresh the theory of Molecular Exclusion Chromatography. Remember, in molecular exclusion chromatography there is a size exclusion interaction of the solute, whereby small solute molecules permeate pores of the stationary phase and are retained ('long' retention time). This is a physical and not a chemical interaction like in other forms of chromatography. Whereas, large solute molecules are blocked from pores of the stationary phase and are readily eluted ('short' retention time).)
- False (Correct. Molecular exclusion chromatography involves a size exclusion interaction of the solute whereby small solute molecules permeate pores of the stationary phase and are retained ('long' retention time). Whereas, large solute molecules are blocked from pores of the stationary phase and are readily eluted ('short' retention time).)
A: False

Q: Supercritical carbon dioxide is used commercially for the extraction of caffeine from water.
- True (Refresh the uses for a supercritical fluid. Supercritical CO_2 is used as a "liquid" to extract from a solid not a liquid phase. US Patent 4820537 - Method for decaffeinating coffee with a supercritical fluid. A method of extracting caffeine from green coffee beans whereby an essentially caffeine-free supercritical fluid is continuously fed to one end of an extraction vessel containing green coffee beans and caffeine-laden supercritical fluid is continuously withdrawn from the opposite end.)
- False (Well done. Supercritical CO_2 is used as a "liquid" to extract from a solid not a liquid phase. US Patent 4820537 - Method for decaffeinating coffee with a supercritical fluid. A method of extracting caffeine from green coffee beans whereby an essentially caffeine-free supercritical fluid is continuously fed to one end of an extraction vessel containing green coffee beans and caffeine-laden supercritical fluid is continuously withdrawn from the opposite end.)
A: False

Q: Molecular Exclusion Chromatography involves a chemical interaction of small solute molecules with the stationary phase.
- True (Refresh the interaction of solutes with the stationary phase in Molecular Exclusion Chromatography. Remember, Molecular Exclusion Chromatography involves a physical size exclusion interaction (not a chemical interaction) of the solute with the stationary phase.)
- False (Correct. Molecular Exclusion Chromatography involves a physical size exclusion interaction (not a chemical interaction) of the solute with the stationary phase.)
A: False

Q: Nitrous oxide, N_2O, does not present an environmental risk by its wide-spread commercial use as a supercritical fluid.
- True (Refresh your knowledge about nitrous oxide. Remember, nitrous oxide is both a greenhouse gas and readily soluble in atmospheric water. Thus, if used as a supercritical fluid and intentionally or inadvertently released in large amounts to the environment, nitrous oxide, N_2O, will contribute to warming of the atmosphere and as a source of 'acid rain'.)
- False (Well done. That's right, nitrous oxide is both a greenhouse gas and readily soluble in atmospheric water. Thus, if used as a supercritical fluid and intentionally or inadvertently released in large amounts to the environment, nitrous oxide, N_2O, will contribute to warming of the atmosphere and as a source of 'acid rain'.)
A: False

Q: Please check all of the times below on which you are available to attend the NMR lectures or tutorials.
- Monday 12 pm
- Tuesday 11 am
- Wednesday 1 pm
- Thursday 11 am
- None of these times suit me.
- I am not interested in attending lectures or tutorials.
A: Monday 12 pm; Tuesday 11 am; Wednesday 1 pm; Thursday 11 am
Feedback: Thank you!

Q: Dipolar attraction between a polar stationary phase and a non-polar solute molecule is a useful extraction mechanism in Solid Phase Extraction.
- True (Refresh the definition of dipolar attraction between molecules. Remember, dipolar attraction is the intermolecular attraction between the dipoles in 'like' polar molecules. Dipolar = two dipoles = one dipole in each molecule.)
- False (Well done. Dipolar attraction is the intermolecular attraction between dipoles in 'like' polar molecules. Dipolar = two dipoles = one dipole in each molecule.)
A: False

Q: The interaction mode in Affinity Chromatography involves the adsorption from a buffered eluent and subsequent covalent attachment of the substrate to the stationary phase.
- True (Refresh the common interaction/extraction modes of chromatography, in particular for affinity chromatography. Chromatography relies on a weak reversible interaction between solute/substrate and the stationary phase. A particular solute/substrate can be eluted (washed) from the stationary phase by adjusting a specific condition of the eluent (mobile) phase. Covalent attachment involves the formation of a new bond that is not necessarily reversible, perhaps needing aggressive chemistry to break the covalent bond. This is not useful for chromatography. The common and useful reversible interaction/extraction modes between solutes/substrates and the stationary phase in chromatography are: - Dispersion attractions (induced dipole-induced dipole interactions) between non-polar (and polar) molecules. These are sometimes referred to as van der Waals forces. Dispersion attractions are weak intermolecular interactions between all organic molecules. They are the only interactions between non-polar molecules. - Dipolar attractions (dipole-dipole interactions) between polar molecules, - Hydrogen bonding - a special case of dipolar attraction, and - Electrostatic attractions between ions and 'charged' molecules.)
- False (Correct. That's right, chromatography relies on a weak reversible interaction between solute/substrate and the stationary phase so that by adusting a specific condition of the eluent (mobile) phase the particular solute/substrate can be eluted (washed) from the stationary phase. Covalent attachment involves the formation of a new bond that is not necessarily reversible, perhaps needing aggressive chemistry to break the covalent bond. This is not useful for chromatography. The common and useful reversible interaction/extraction modes between solutes/substrates and the stationary phase in chromatography are: - Dispersion attractions (induced dipole-induced dipole interactions) between non-polar (and polar) molecules. These are sometimes referred to as van der Waals forces. Dispersion attractions are weak intermolecular interactions between all organic molecules. They are the only interactions between non-polar molecules. - Dipolar attractions (dipole-dipole interactions) between polar molecules, - Hydrogen bonding - a special case of dipolar attraction, and - Electrostatic attractions between ions and 'charged' molecules.)
A: False

Q: A fragment ion must always have a lower m/z than that of the molecular ion from which it is formed.
- True (Correct. A fragment ion (as opposed to a recombination ion) always has a lower m/z than the parent molecular ion.)
- False
A: True

Q: Chemical ionisation involves using a reagent gas, such as methane or ammonia, to remove an electron from a molecule.
- True (Remember the difference between chemical ionisation and electron ionisation. Chemical ionisation is a soft ionisation technique that produces intact protonated molecule ions (MH^+) in the mass spectrum. Whereas, electron ionization (EI) is a hard ionisation technique that involves bombardment of vaporized gaseous molecules with a beam of electrons with, typically, energy of 70 eV. This knocks an electron from the molecule to produce a cation radical.)
- False (Well done. That's right, chemical ionisation is a soft ionisation technique that produces intact protonated molecule ions (MH^+) in the mass spectrum. Whereas, electron ionization (EI) is a hard ionisation technique that involves bombardment of vaporized gaseous molecules with a beam of electrons with, typically, energy of 70 eV. This knocks an electron from the molecule to produce a cation radical.)
A: False

Q: The specific nature of the immobilized ligand means that the prepared stationary phase can be used for a wide variety of solute types in Affinity Chromatography.
- True (Refresh the eason for preparing and attaching a ligand to the support material in Affinity Chromatography. You design and prepare a particular ligand to attach to the support material so as to target a specific solute in Affinity Chromatography.)
- False (Correct. That's right, the opposite is true. You design and prepare a particular ligand to attach to the support material so as to target a specific solute.)
A: False

Q: The solid phase extraction (SPE) of an organic solute from an aqueous sample involves four steps in the following order:

1. Rinse the extraction phase to prepare it,

2. Absorb the solutes to the extraction phase,

3. Condition the extraction phase before elution.

4. Elute the solutes from the extraction phase.
- True (Refresh the order of the four main steps involved in Solid Phase Extraction (SPE). Remember, the four main steps (CARE) in SPE are: 1. Condition the solid extraction phase 2. Adsorb (retention) of sample solutes 3. Rinse solid extraction phase with “weak” solvent to remove weakly adsorbed solutes, 4. Elute strongly adsorbed analytes (solutes) with “stronger” solvent. Take CARE don’t RACE!)
- False (Correct. Well done, the four main steps (CARE) in SPE are: 1. Condition the solid extraction phase 2. Adsorb (retention) of sample solutes 3. Rinse solid extraction phase with “weak” solvent to remove weakly adsorbed solutes, 4. Elute strongly adsorbed analytes (solutes) with “stronger” solvent. Take CARE don’t RACE!)
A: False

Q: The visual detection and analysis by Thin Layer Chromatography of α-amino acids involves exposing the TLC plate to iodine that adds across the unsaturated double bond.
- True (Refresh the chemical structure of α-amino acids. Remember, α-amino acids do not contain an unsaturated double bond. (Iodine can chemically react and add across an unsaturated double bond for some compounds))
- False (Correct. a-amino acids do not contain an unsaturated double bond. (Iodine can chemically react and add across an unsaturated double bond for some compounds))
A: False

Q: Semi-rigid cross-linked macromolecular organic co‑polymers are used as stationary phases in Molecular Exclusion Chromatography.
- True (That's right. The stationary phase must be an open network that can exclude some molecules on the basis of their molecular size (or more correctly hydrated/solvated size). The stationary phase materials used for Molecular Exclusion Chromatography are based on semi-rigid cross-linked macromolecular organic co‑polymers, Sephadex™, a co-polymer of Dextran (monomer) and Glycerin (cross-linker) Bio-Gel P™, a co-polymer of Acrylamide (monomer) and N,N-Methylenebisacrylamide.)
- False (Refresh the essential characteristics that are required for a stationary phase in molecular exclusion chromatography. Remember, the stationary phase must be an open network that can exclude some molecules on the basis of their molecular size (or more correctly hydrated/solvated size). The stationary phase materials used for Molecular Exclusion Chromatography are based on semi-rigid cross-linked macromolecular organic co‑polymers, Sephadex™, a co-polymer of Dextran (monomer) and Glycerin (cross-linker) Bio-Gel P™, a co-polymer of Acrylamide (monomer) and N,N-Methylenebisacrylamide.)
A: True

Q: The diagram below is representative of the d orbital spiltting for a tetrahedral complex [Image]
- false
- true
A: false

Q: Considering the molecular orbital diagram of O2.

O2(2-) is paramagnetic
- false
- true
A: false

Q: Choose the correct electron configuration for Co.
- [Ar] 3d7
- [Ar] 3d7 4s2
- [Ar] 3d9
- [Ar] 3d1 4s2 4p6
A: [Ar] 3d7 4s2

Q: A certain element X was found to form 3 compounds:

XCl2, XCl4, XCl6. One of its oxides has the formula XO3 and X reacts with sodium to for Na2X.

a. Is X a metal or non metal

b. In which group would you expect X to belong to

c. What kind of hybrid orbitals would X use in XF6

d. Which element is X?
1. [...]
2. [...]
3. [...]
4. [...]
A: non metal / sulfur / 6 / sp3d2; non metal / sulfur / 6 / sp3d2; 6 / sp3d2 / non metal / sulfur; non metal / sulfur / 6 / sp3d2

Q: Select the correct response.
The shape of the molecule BrF_3 will be:
- tetrahedral
- distorted T-shape
- pyramidal
- triangular
A: distorted T-shape

Q: Calculate the lattice energy for KCl using the data below.
A: 719

Q: [Co(H2O)5(NH3)]3+ and [Co(H2O)(NH3)5]3+ are isomers
- false
- true
A: false

Q: (Crystal Field Theory) When the valence d orbitals of the central metal ion are split in energy in an octahedral ligand field, which orbitals are raised least in energy?
- dxy and dx2-y2
- dxz and dyz
- dxy, dxz and dyz
- dx2-y2 and dz2
- dxz, dyz and dz2
A: dxy, dxz and dyz

Q: The effective nuclear charge for a valence electron in Al3+ is [...]
A: 8.85
Feedback: Al3+ = 1s2 2s2 2p6 3s0 3p6 so a valence electron is in 2p6

Q: Which is the more metallic element
- S
- Ge
A: Ge

Q: Give the chemical names for [Ag(NH3)2][BF4]

Q: Using the data below:

The lattice energy for KCl is [...] [Image]
A: 719 kJmol-1

Q: (Crystal Field Theory) Which one of the following statements is FALSE?
- Low spin complexes contain strong field ligands.
- In high spin octahedral complexes, oct is less than the electron pairing energy, and is relatively very small.
- Low spin complexes can be paramagnetic.
- Diamagnetic metal ions cannot have an odd number of electrons.
- In an octahedral crystal field, the d electrons on a metal ion occupy the eg set of orbitals before they occupy the t2g set of orbitals.
A: In an octahedral crystal field, the d electrons on a metal ion occupy the eg set of orbitals before they occupy the t2g set of orbitals.

Q: The HOMO of the diatomic molecule F2 is a [...] orbital
A: antibonding

Q: Strong field ligands such as CN-:
- usually produce high spin complexes and high crystal field splittings.
- usually produce high spin complexes and small crystal field splittings.
- usually produce low spin complexes and small crystal field splittings.
- usually produce low spin complexes and high crystal field splittings.
- cannot form low spin complexes.
A: usually produce low spin complexes and high crystal field splittings.

Q: Give the values for n and l for a 3s orbital
- n = 3, l = 2, 1, 0, -1, -2
- n = 3, l = 0
- n = 2, l = 2, 1, 0, -1, -2
- n = 3, l = 3, 2, 1
A: n = 3, l = 0

Q: The reason that complexing / chelating agents are often employed in visible (spectrophotometric) analysis is that they form complexes with intense colors (high molar absorptivity)
- false
- true
A: true

Q: Give three factors that effect lattice energy are

1. [...]
2. [...]
3. [...]
A: Charge / Size / Packing; Charge / Size / Packing; Charge / Size / Packing

Q: Consider the complex ion [Mn(OH2)6]2+ with 5 unpaired electrons. Which response includes all the following statements that are true, and no false statements?

I. It is diamagnetic.

II. It is a low spin complex.

III. The metal ion is a d5 ion.

IV. The ligands are weak field ligands.

V. It is octahedral.
- I, IV
- I, II
- III, IV, V
- III, IV
- II, V
A: III, IV, V

Q: Which has the highest first ionization energy, Ca or Ga? (Consider all factors, Zeff, size, charge etc).
- Ga
- Ca
A: Ca

Q: For [Mn(CN)6]4-, give the oxidation state of the metal and its dn configuration and coordination number.
- oxidation state = 2, coordination number = 6, d electrons = 5
- oxidation state = 3, coordination number = 4, d electrons = 5
- oxidation state = 2, coordination number = 4, d electrons = 0
- oxidation state = 5, coordination number = 4, d electrons = 3
- oxidation state = 2, coordination number = 4, d electrons = 5
A: oxidation state = 2, coordination number = 6, d electrons = 5

Q: Valence Bond Theory) The coordination complex, [Cu(OH2)6]2+ has one unpaired electron. Which of the following statements are true?

(1) The complex is octahedral.

(2) The Cu is oxidation state 1.

(3) The complex is d2sp3 hybridized.

(4) The complex is diamagnetic.

(5) The coordination number is 6.
- 1,3,5
- 4,5
- 2,3,5
- 1,4
- 2,3
A: 1,3,5

Q: What is the oxidation number of the central metal atom in the coordination compound [Pt(NH3)3Cl]Cl?
- 0
- -1
- +1
- +3
- +2
A: +2

Q: An absorption peak near 20 000 cm^-1 in the [...] spectrum of the complex ion (Ti(H_2O)_6)^3+ is due to a [...] electron transition.
A: visible; d-d / d - d

Q: The systematic name for the transition metal complex K_2{FeCl_5(H_2O)} is [...].
A: Potassium aquapentachloroferrate(III)

Q: Using the data below, calculate the lattice energy in kJ mol -1 for KCl. (Just enter a numerical value into the answer box, without units)

Step Delta H (kJ mol –1)

Sublimation of K(s) +89

Ionization of K(g) +425

Dissociation of Cl2(g) +244

Electron Gain by Cl(g) -355

Formation of KCl(s) -438
A: 719

Q: Choose the more likely electron configuration for Mn2+: [Ar] 4s2 3d3 or [Ar]3d5
- [Ar]3d5 (metals always lose the electrons from the highest n level first.)
- Ar] 4s2 3d3
A: [Ar]3d5

Q: In Experiment 2 in the laboratory, you synthesized the pale green complex (Et_4N)_2(MnCl_4), in which Et = ethyl. Its systematic name is [...].
A: tetraethylammonium tetrachloromanganate(II)

Q: A chelating agent employed in medicine is dl-penicillamine.
- true
- false
A: true

Q: The number of electrons in AsF6- is
- 88
- 60
- 48
- 47
A: 48

Q: What is the oxidation state of Mn in the following complex:

[Mn(CN)6]4-
A: 2 2+ (II)

Q: Ionisation energy increases descending a group
- false
- true
A: false

Q: A scale of values based on the mean of the electron affinity (EA) and the ionization potential (IP) of an atom is a measure of its
A: Electronegativity

Q: Which of the following statements are incorrect
- Transition metals have valence electrons are in p orbitals
- Lanthanum is a transition metal
- Transition metals can have varied oxidation states
- Transition metals can form complexes that are highly colored
A: Transition metals have valence electrons are in p orbitals; Lanthanum is a transition metal

Q: The major achievement of Mendeleyev’s version of a Periodic Table of elements was the prediction of [...] elements.
A: unknown

Q: Newlands was derided for bringing music into chemistry when he devised the “Law of Octaves” in 1866. The main reason for the failure of this version of periodicity of the elements was that not all elements, particularly the [...], were known at that time.
A: noble gases

Q: Choose the correct response.
The element uranium (U) is a:
- alkali metal
- actinide
- lanthanide
- transition metal
A: actinide

Q: How many unpaired electrons are there in a strong field iron(II) complex?
- 2
- 4
- 6
- 0
- 1
A: 0

Q: Consider the coordination compound, K2[Cu(CN)4]. A coordinate covalent bond exists between
- K+ and [Cu(CN)4]2-
- K+ and CN-
- K+ and Cu2+
- C and N in CN-
- Cu2+ and CN-
A: Cu2+ and CN-

Q: The ______ sphere is enclosed in brackets in formulas for complex species, and it includes the central metal ion plus the coordinated groups.
- oxidation
- coordination
- chelating
- donor
- ligand
A: coordination

Q: In coordination chemistry, the donor atom of a ligand is
- the atom in the ligand that accepts a share in an electron pair from the metal
- the atom in the ligand that shares an electron pair with the metal
- the central metal ion
- a Lewis acid
- the counter ion
A: the atom in the ligand that shares an electron pair with the metal

Q: (Valance Bond Theory) Magnetic measurements indicate that [Co(OH2)6]2+ has 3 unpaired electrons. Therefore, the hybridization of the metal's orbitals in [Co(OH2)6]2+ is:
- d2sp3
- sp2d
- dsp2
- sp3d2
- sp3
A: sp3d2

Q: Select the correct IUPAC name for: [FeF4(OH2)2]-
- diaquatetrafluoroiron(I) ion
- diaquatetrafluoroferrate(III) ion
- diaquatetrafluoroiron(III) ion
- diaquatetrafluoroferrate(I) ion
A: diaquatetrafluoroferrate(III) ion

Q: Which element is not a transition element?
- Ru
- Os
- Mn
- Pb
- Nb
A: Pb

Q: Which has the higher ionization energy: Mg or Ca?
- Ca
- Mg (electrons closer to nucleus)
A: Mg

Q: In which one of the following species does the transition metal ion have d3 electronic configuration?
- [Ni(OH2)6]2+
- [Fe(CN)6]3-
- [CoF6]3-
- [Cr(NH3)6]3+
- [Co(OH2)6]2+
A: [Cr(NH3)6]3+

Q: The bond order for O2?
- 1
- 3
- 4
- 2
A: 2

Q: Which of the following elements is not a transition element: Cu, Zn or Pt
A: Zn zinc

Q: Which of the following is the correct name for:

[CrCl2(NH3)4]+
- tetraamminedichlorochromium(II)
- tetraamminedichlorochromium(III)
- tetraammoniabischlorochromium(II)
- chromium dichloro tetra ammonia (I)
A: tetraamminedichlorochromium(III)

Q: Choose the correct response.
Use the symbol [Ar] for the 18 electrons that make up an argon core. The electronic configuration for a Cr(II) species is:
- [Ar] 3d^2
- [Ar] 3d^8
- [Ar] 3d^4
- [Ar] 3d^6
A: [Ar] 3d^4

Q: Given the list of ligands and their corresponding names, choose the pair that disagree.
- NH3 ammine
- H2O aqua
- Cl- chloro
- CN- cyanide
- OH- hydroxo
A: CN- cyanide

Q: Which name-formula combination is NOT correct?
- [Co(NH3)4(OH2)I]SO4 tetraammineaquaiodocobalt(III) sulfate
- K[Cr(NH3)2Cl4] potassium diamminetetrachlorochromate(III)
- [Ni(CO)4] tetracarbonylnickel(0)
- Ca[PtCl4] calcium tetrachloroplatinate(II)
- [Mn(CN)5]2- pentacyanomanganate(II) ion
A: [Mn(CN)5]2- pentacyanomanganate(II) ion

Q: The electronegativities of atoms increase down a group in the Periodic Table.
- false
- true
A: false

Q: What is the effect of Hund’s Rule on the electronic configuration of the nitrogen (N) atom?
All [...] electrons in the 2p orbital have [...] spins.
A: three; parallel

Q: Select the correct response.
The shape of the anion [IF_4]^- will be:
- square planar
- octahedral
- distorted T-shape
- tetrahedral
A: square planar

Q: What is meant by the Pauli Exclusion Principle?
No [...] electrons in an atom can have the same set of [...] quantum numbers.
A: two; four

Q: What is the coordination number and oxidation number of the central atom in [CoCl4(NH3)2]-
- coordination number = 6, oxidation number = 3
- coordination number = 4, oxidation number = 4
- coordination number = 4, oxidation number = 3
- coordination number = 6, oxidation number = 4
A: coordination number = 6, oxidation number = 3

Q: Select the correct IUPAC name for: [Co(NH3)6]2+
- hexammoniacobaltate(II) ion
- hexaamminecobaltate(II) ion
- hexammoniacobalt ion
- hexammoniacobalt(II) ion
- hexaamminecobalt(II) ion
A: hexaamminecobalt(II) ion

Q: Which would you expect to have the highest lattice energy
- NaCl
- Al2O3
A: Al2O3

Q: The width of a mass spectral peak at m/z 150 is found to be 0.4 Th when measured at 50% peak height. The 50% mass resolution of the mass spectrometer is 60.
- True (Check your calculation.)
- False (Correct.)
A: False

Q: Not all molecules produce a base peak in their mass spectrum.
- True (Note: All mass spectrums have a base peak = most intense peak)
- False (Correct. All mass spectrums have a base peak = most intense peak)
A: False

Q: The number of 70 eV electrons in an ion source can be increased by using an electron multiplier.
- True (Note: An electron multiplier is used to measure detector signal not to generate more electrons in the ion source.)
- False (Well done. An electron multiplier is used to measure detector signal not to generate more electrons in the ion source.)
A: False

Q: A fragment ion must always have a lower m/z than that of the molecular ion from which it is formed.
- True (Correct. A fragment ion (as opposed to a recombination ion) always has a lower m/z than the parent molecular ion.)
- False (Note: A fragment ion (as opposed to a recombination ion) always has a lower m/z than the parent molecular ion.)
A: True

Q: The simple bond cleavage in an odd-electron molecule ion produces an even-electron fragment ion.
- True (Well done. Bond rupture of radical cation (M+•) produces an even-electron ion (most common fragmentation mechanism))
- False (Note: Bond rupture of radical cation (M+•) produces an even-electron ion (most common fragmentation mechanism))
A: True

Q: A single carbon-12 cation has a m/z of exactly 12.0000 Th.
- True (Correct. • one dalton is 1/12 the mass of a single 12C atom • one 12C atom has a mass of 12.0000 Da • one 12C cation has a m/z of 12.0000 Th (thomson))
- False (Note: • one dalton is 1/12 the mass of a single 12C atom • one 12C atom has a mass of 12.0000 Da • one 12C cation has a m/z of 12.0000 Th (thomson))
A: True

Q: There are 5 “rings + double bonds” associated with a C7H5NOF2+• molecular ion.
- True (Correct. RDB = IV – 1/2I + 1/2III + 1 (for AI BII CIII DIV) = 7 – ½ (7) + ½ (1) + 1 = 5)
- False (Check your calculation. Remember to use use RDB = IV – 1/2I + 1/2III + 1 (for AI BII CIII DIV))
A: True

Q: Bromine has two isotopes with masses of 79 and 81 Da. The molecular ion for Br_2 occurs at m/z 160.
- True (Remember. The molecular ion (as opposed to base peak ion) contains most abundant isotopes of all elements. • Bromine isotopes: 79Br = 51%, 81Br = 49% • Br_2 molecular ion = m/z 158 ( 79Br 79Br)+•)
- False (Well done. • molecular ion (as opposed to base peak ion) contains most abundant isotopes of all elements • Bromine isotopes: 79Br = 51%, 81Br = 49% • Br_2 molecular ion = m/z 158 ( 79Br 79Br)+•)
A: False

Q: Electrospray ionization is an example of a “soft ionization” technique.
- True (Correct. • Electron ionisation (EI) (~ 70 eV) is a hard ionisation technique • Soft ionisation techniques include: chemical ionization (CI) photoionization (PI) fast atom bombardment (FAB) laser desorption (LD) electrospray ionization (ESI) atmospheric pressure ionization (API))
- False (Remember: • Electron ionisation (EI) (~ 70 eV) is a hard ionisation technique • Soft ionisation techniques include: chemical ionization (CI) photoionization (PI) fast atom bombardment (FAB) laser desorption (LD) electrospray ionization (ESI) atmospheric pressure ionization (API))
A: True

Q: Mass analyzers are usually maintained at a typical vacuum of 10 kPa
- True (Note: Typically, a mass spectrometer operates at a vacuum < 6.6 x 10-3 Pa.)
- False (Well done! Typically, mass spectrometer vacuum < 6.6 x 10-3 Pa.)
A: False

Q: Silica gel is commonly used as the stationary phase in Thin Layer Chromatography for the analysis of non-polar compounds.
- True (Refresh the polarity of stationary phases used in chromatography. Remember, Silica gel is a polar stationary phase as it contains terminal silanol groups (-Si-OH) = polar sites)
- False (Correct. Silica gel contains terminal silanol groups (-Si-OH) = polar sites)
A: False

Q: Steric hindrance of the donor-ligand attachment to the support material is not a problem in Affinity chromatography.
- True (Refresh the interaction between the attached ligand and a target molecule. Remember, often a short-chain alkyl spacer is needed between the support material and the ligand to eliminate steric hindrance of the molecular interaction of the ligand to a bulky target molecule (such as a protein).)
- False (Correct. Often a short-chain alkyl spacer is needed between the support material and the ligand to eliminate steric hindrance of the molecular interaction of the ligand to a bulky target molecule (such as a protein).)
A: False

Q: Fast Atom Bombardment (FAB) is a “hard” ionisation method used in mass spectrometry.
- True (Refresh "soft and "hard" ionisation methods. Electron ionisation (EI) (~ 70 eV) is a hard ionisation technique. Soft ionisation techniques include: chemical ionization (CI), photoionization (PI), fast atom bombardment (FAB), laser desorption (LD), electrospray ionization (ESI), & atmospheric pressure ionization (A)
- False (Well done. Electron ionisation (EI) (~ 70 eV) is a hard ionisation technique. Soft ionisation techniques include: chemical ionization (CI), photoionization (PI), fast atom bombardment (FAB), laser desorption (LD), electrospray ionization (ESI), & atmospheric pressure ionization (API))
A: False

Q: The width of a mass spectral peak at m/z 180 Th is found to be 0.6 Th when measured at 10% peak height. The 10% mass resolution of the mass spectrometer is 300.
- True (Well done.)
- False
A: True
Feedback: Check your calculation.

Q: All molecules produce a base peak in their mass spectrum.
- True (Correct. Base peak in a mass spectrum is the commonly observed most abundant peak that is assigned a peak intensity of 100% to which all other peak intensities are referred.)
- False (Refresh the difference between a base peak and molecular ion peak in a mass spectrum.)
A: True

Q: A molecule containing two nitrogen atoms will produce an even-electron ion having an odd mass number.
- True (Refresh the Nitrogen Rule in mass spectrometry. Molecule containing odd-number of nitrogen atoms has an odd-numbered molecular weight (nitrogen is trivalent). Odd-numbered molecular ion implies molecule contains either 1, 3, 5, etc, nitrogen atoms.)
- False (Correct. Nitrogen Rule in Mass Spectrometry: Molecule containing odd-number of nitrogen atoms has an odd-numbered molecular weight (nitrogen is trivalent). Odd-numbered molecular ion implies molecule contains either 1, 3, 5, etc, nitrogen atoms.)
A: False

Q: Fragmentation of a molecule can occur at a radical site where an unpaired electron is donated to form a new bond.
- True (Well done. Fragmentation of radical cations by structure rearrangement mechanism can occur at the radical site by donation of unpaired electron to form new bond. (fragmentation also at charge site where positive charge attracts electron to form new bond ))
- False (Refresh fragmentation of a radical ion. Fragmentation of radical cations by structure rearrangement mechanism can occur at the radical site by donation of unpaired electron to form new bond. (fragmentation also at charge site where positive charge attracts electron to form new bond ))
A: True

Q: The most favoured ionisation site in a molecule is associated with the removal of the electron with the highest ionisation energy.
- True (Refresh: Most favoured ionization site involves removal of the electron of lowest ionization energy.)
- False (Correct. Most favoured ionization site involves removal of the electron of lowest ionization energy.)
A: False

Q: Samples of approximately 10-3 – 10-6 gram are required to produce a mass spectrum.
- True (Refresh required sample sizes in mass spectrometry. Mass Spectrometry can identify compounds using ~1 ng – 1 pg)
- False (Correct. Mass Spectrometry can identify compounds using ~1 ng – 1 pg (10-9 – 10-12 g) of sample)
A: False

Q: A minimum electron energy of 70 eV is required for the electron ionisation of a molecule.
- True (Refresh ionisation energies needed to remove a electron (bonding and non-bonding) from a molecule. Ionisation of sigma- and pi-bonds typically requires only 7 - 13 eV. Electron ionisation at 70 eV is normal practise and used to produce characteristic fragmentation ions from the molecular ion in the mass spectrum that can be compared to reference spectra for identifications purposes.)
- False (Well done. Ionisation of sigma- and pi-bonds typically requires only 7 - 13 eV. Electron ionisation at 70 eV is normal practise and used to produce characteristic fragmentation ions from the molecular ion in the mass spectrum that can be compared to reference spectra for identifications purposes.)
A: False

Q: Chlorine has two isotopes with masses

of 35 and 37 Da. The molecular ion for

Cl_2 occurs at m/z 70.
- True (Correct. The molecular ion is the peak of highest intensity containing the most abundant isotopes in group of molecule peaks at highest m/z values in mass spectrum associated with the intact molecule. Chlorine isotopes: 35Cl 34.968 85 Da, 75.78% 37Cl 36.965 90 Da, 24.22% Chlorine molecular ion is 35Cl-35Cl = m/z 70 Th)
- False (Refresh the definition of a molecular ion. Refresh the identification of the molecular ion from a group of similar m/z ssignals. Chlorine isotopes: 35Cl 34.968 85 Da, 75.78% 37Cl 36.965 90 Da, 24.22%)
A: True

Q: A quadrupole ion trap can be used as a mass analyser in a mass spectrometer.
- True (Well done. Separation of ions according to their mass-to-charge ratio (m/z) occurs in the mass analyser. The mass analyser can be: • magnetic sector • quadrupole filter • quadrupole ion trap • time-of-flight)
- False (Refresh the different types of mass analysers used in mass spectrometry. Separation of ions according to their mass-to-charge ratio (m/z) occurs in the mass analyser. The mass analyser can be: • magnetic sector • quadrupole filter • quadrupole ion trap • time-of-flight)
A: True

Q: Is the HOMO of F2, a bonding or antibonding orbital?
A: antibonding

Q: The retention factor is a useful quantitative measure of a compound in Thin Layer Chromatography.
- True (Refresh the difference between qualitative and quantitative measures in chromatography. Remmeber, the retention factor is a qualitative indicator, wheras, the signal intensity (peak area, etc) is a quantitative measure.)
- False (Correct. The retention factor is a qualitative indicator, wheras, the signal intensity (peak area, etc) is a quantitative measure.)
A: False

Q: A supercritical fluid will be converted from a gas to a liquid when the pressure is increased above the critical pressure.
- True (Refresh the definition of a supercritical fluid (picture the phase diagram of the supercritical region). Remember, a supercritical fluid is a “fluid” whose temperature and pressure are above the critical temperature and pressure point in its phase diagram; it has properties of both a liquid and a gas. That is, a gas at a temperature and pressure above its critical point that cannot be liquefied.)
- False (Well done. A supercritical fluid is a “fluid” whose temperature and pressure are above the critical temperature and pressure point in its phase diagram; it has properties of both a liquid and a gas. That is, a gas at a temperature and pressure above its critical point that cannot be liquefied.)
A: False

Q: The van der Waals interaction forces between unlike molecules are a useful extraction mode in Solid Phase Extraction.
- True (Refresh the different interaction modes, between molecules, ions and molecules, and ions and ions. Remember, the term "van der Waals interaction forces" is used to describe a group of weak intermolecular attraction forces between like molecules (e.g. dipole-dipole interactions between polar molecules).)
- False (Well done. The term "van der Waals interaction forces" is used to describe a group of weak intermolecular attraction forces between like molecules (e.g. dipole-dipole interactions between polar molecules).)
A: False

Q: The “capacity factor” is a measure of the number of moles of solute in the mobile phase during chromatography.
- True (Refresh the definition (and equation) for the term "capacity factor" as used in chromatography. Remember, the “capacity factor” is a measure of the solute retention or partitioning between the stationary and mobile phase.)
- False (Well done. The “capacity factor” is a measure of the solute retention or partitioning between the stationary and mobile phase.)
A: False

Q: The “column dead time” is a measure of the amount of mobile phase needed to elute a solute during chromatography.
- True (Refresh the definition of column dead (or void) time, tm (or t0) in chromatography. Remember, the column dead (or void) time, tm (or t0) is the time for an unretained solute to elute. That is, the solute spends zero time in the stationary phase and all the time in the mobile phase.)
- False (Well done. The column dead (or void) time, tm (or t0) is the time for an unretained solute to elute. That is, the solute spends zero time in the stationary phase and all the time in the mobile phase.)
A: False

Q: Semi-rigid cross-linked macromolecular organic co‑polymers are used as stationary phases in Molecular Exclusion Chromatography.
- True (That's right. The stationary phase must be an open network that can exclude some molecules on the basis of their molecular size. The stationary phase materials used for Molecular Exclusion Chromatography are based on semi-rigid cross-linked macromolecular organic co‑polymers, Sephadex™, a co-polymer of Dextran (monomer) and Glycerin (cross-linker) Bio-Gel P™, a co-polymer of Acrylamide (monomer) and N,N-Methylenebisacrylamide.)
- False (Refresh the essential characteristics that are required for a stationary phase in molecular exclusion chromatography. Remember, the stationary phase must be an open network that can exclude some molecules on the basis of their molecular size. The stationary phase materials used for Molecular Exclusion Chromatography are based on semi-rigid cross-linked macromolecular organic co‑polymers, Sephadex™, a co-polymer of Dextran (monomer) and Glycerin (cross-linker) Bio-Gel P™, a co-polymer of Acrylamide (monomer) and N,N-Methylenebisacrylamide.)
A: True

Q: The Partition Coefficient is a measure of the partitioning of all ionised forms of a solute between an organic phase and an aqueous phase.
- True (Refresh the definition of the partition coefficient (K). Remember, The partition coefficient (K) is effectively the equilibrium constant for the partitioning of a neutral solute (X) between two chemically different phases.)
- False (Well done. The partition coefficient (K) is effectively the equilibrium constant for the partitioning of a neutral solute (X) between two chemically different phases.)
A: False

Q: Dipolar attraction between a polar stationary phase and a non-polar solute molecule is a useful extraction mechanism in Solid Phase Extraction.
- True (Refresh the definition of dipolar attraction between molecules. Remember, dipolar attraction is the intermolecular attraction between dipoles in "like" molecules.)
- False (Well done. Dipolar attraction is the intermolecular attraction between dipoles in "like" molecules.)
A: False

Q: Large solute molecules are retained in the pores of the stationary phase and elute after small solute molecules in Molecular Exclusion Chromatography.
- True (Refresh the theory of Molecular Exclusion Chromatography. Remember, in molecular exclusion chromatography there is a size exclusion interaction of the solute, whereby small solute molecules permeate pores of the stationary phase and are retained (“long” retention time). Whereas, large solute molecules are blocked from pores of the stationary phase and are readily eluted (“short” retention time).)
- False (Correct. Molecular exclusion chromatography involves a size exclusion interaction of the solute whereby small solute molecules permeate pores of the stationary phase and are retained (“long” retention time). Whereas, large solute molecules are blocked from pores of the stationary phase and are readily eluted (“short” retention time).)
A: False

Q: The Retention Factor is a measure of how a solute is retained by the stationary phase in Thin Layer Chromatography.
- True (Correct. The retention factor (Rf) is a measure of solute interaction with the stationary phase adsorbent.)
- False (Refresh the definition of the "retention factor" in thin layer chromatography. Remember, the retention factor (Rf) is a measure of solute interaction with the stationary phase adsorbent.)
A: True

Q: Alumina is commonly used as a stationary phase in Thin Layer Chromatography for the analysis of strongly polar compounds.
- True (Refresh the chemical nature of stationary phases used in thin layer chromatography. Remember, silica gel is preferred for polar compounds like amino acids and sugars, whereas, alumina is preferred for weakly polar compounds like alkaloids and steroids.)
- False (Well done. Silica gel is preferred for polar compounds like amino acids and sugars, whereas, alumina is preferred for weakly polar compounds like alkaloids and steroids.)
A: False

Q: The “adjusted retention time” is a measure of the amount time the solute spends in the mobile phase.
- True (Refresh the definition of "adjusted retention time" in chromatography theory. Remember, the "adjusted retention time" is a measure of time that the solute spends in the stationary phase.)
- False (Correct. Thre "adjusted retention time" is a measure of time that the solute spends in the stationary phase.)
A: False

Q: Molecular Exclusion Chromatography involves a chemical interaction of small solute molecules with the stationary phase.
- True (Refresh the interaction of solutes with the stationary phase in Molecular Exclusion Chromatography. Remember, Molecular Exclusion Chromatography involves a physical size exclusion interaction of the solute with the stationary phase.)
- False (Correct. Molecular Exclusion Chromatography involves a physical size exclusion interaction of the solute with the stationary phase.)
A: False

Q: The efficiency of Supercritical Fluid Extraction can be improved by increasing the pressure on the supercritical fluid so as to increase its density.
- True (Well done. Control over the SFE procedure is afforded by varying the pressure to extract “difficult” chemicals (higher density of SF at increased pressure gives increased eluent strength). Another method to improve the efficiency of SFE is to add an appropriate modifying agent to the supercritical fluid.)
- False (Refresh the common methods to increase the efficiency of Supercritical Fluid Extraction. Remember, one method of control over the SFE procedure is afforded by varying the pressure to extract “difficult” chemicals (higher density of SF at increased pressure gives increased eluent strength). Another method is to add an appropriate modifying agent to the supercritical fluid.)
A: True