DOC PREVIEW
CU-Boulder CHEM 5181 - Review Questions

This preview shows page 1-2-3-4-5 out of 15 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 15 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

1Clicker Review Questions on MS Interpretation(contributed by students)CU- Boulder CHEM 5181Mass Spectrometry & ChromatographyProf. Jose-Luis JimenezFall 2006Clicker Question • The most favored radical and charge sites in the molecular ion arise from the loss of the molecule’s electron of lowest ionization energy. Favorability for ionization is generally:• (a) π- electron s > σ-electrons > n-electrons • (b) n-electrons > π- electrons > σ-electrons• (c) n-electrons > π- electrons > σ-electrons• (d) σ-electrons > n-electrons > π- electrons2Clicker Question • The most favored radical and charge sites in the molecular ion arise from the loss of the molecule’s electron of lowest ionization energy. Favorability for ionization is generally:• (a) π- electron s > σ-electrons > n-electrons • (b) n-electrons > π- electrons > σ-electrons• (c) n-electrons > π- electrons > σ-electrons• (d) σ-electrons > n-electrons > π- electronsWhich of the following is the correct order of neutral loss from the fragmentation of this molecule.a. C6H13 > C5H11 > C2H5 > C3H7b C6H13 > C5H11 > C3H7 > C2H5C. C2H5 > C3H7 > C5H11 > C6H13D. It is impossible to determine the correct orderE. The answer is not shown above. C5H11 C2H5 C6H13 C3H73Which of the following is the correct order of neutral loss from the fragmentation of this molecule.a. C6H13 > C5H11 > C2H5 > C3H7b C6H13 > C5H11 > C3H7 > C2H5C. C2H5 > C3H7 > C5H11 > C6H13D. It is impossible to determine the correct orderE. The answer is not shown above. C5H11 C2H5 C6H13 C3H7 Clicker Question 1• An even electron ion (EE+)A. Can typically decompose to form another EE+B. Can typically decompose to an OE+.and a neutralC. Can be a fragment from an OE+.D. A and CE. B and C4Clicker Question 1• An even electron ion (EE+)A. Can typically decompose to form another EE+B. Can typically decompose to an OE+.and a neutralC. Can be a fragment from an OE+.D. A and CE. B and CClicker Question 2• The molecular ion in EI:A. Has to be an Odd Electron ion.B. Can have an odd number of Nitrogen and an odd mass number.C. Might or might not be the most intense peak in the spectrum.D. Might or might not be observed in the spectrumE. All of the above.5Clicker Question 2• The molecular ion in EI:A. Has to be an Odd Electron ion.B. Can have an odd number of Nitrogen and an odd mass number.C. Might or might not be the most intense peak in the spectrum.D. Might or might not be observed in the spectrumE. All of the above.Clicker Question• If an OE+· ion produces an EE+ ion, how man bonds were cleaved?• (a) 1 or 2• (b) 1 or 3• (c) 2 or 3• (d) 1, 2, or 36Clicker Question• If an OE+· ion produces an EE+ ion, how man bonds were cleaved?• (a) 1 or 2• (b) 1 or 3• (c) 2 or 3• (d) 1, 2, or 3Which of the following are true?– i: A molecular ion containing 3 nitrogens will have an even mass– ii: EE are common in the low masses– iii: The molecular ion will always be the peak of the highest intensity– iv: Important peaks rarely come from losses of 21-25A: i, ii, ivB: ii, ivC: iii, ivD: i, iiiE: All are true7Which of the following are true?– i: A molecular ion containing 3 nitrogens will have an even mass– ii: EE are common in the low masses– iii: The molecular ion will always be the peak of the highest intensity– iv: Important peaks rarely come from losses of 21-25A: i, ii, ivB: ii, ivC: iii, ivD: i, iiiE: All are trueClicker Question 2• What would be the expected relative intensities of a spectrum that had Br5 present?A. A(9), A+1(60), A+2(100), A+3(57), A+4(8)B. A(9), A+2(60), A+4(100), A+6(57), A+8(8)C. A(17), A+1(68), A+2(100), A+3(65), A+4(16)D. A(11), A+2(51), A+4(100), A+6(97), A+8(48), A+10(9)E. None of the above8Clicker Question 2• What would be the expected relative intensities of a spectrum that had Br5 present?A. A(9), A+1(60), A+2(100), A+3(57), A+4(8)B. A(9), A+2(60), A+4(100), A+6(57), A+8(8)C. A(17), A+1(68), A+2(100), A+3(65), A+4(16)D. A(11), A+2(51), A+4(100), A+6(97), A+8(48), A+10(9)E. None of the aboveClicker Question 2• Related to Stevenson's Rule what is true when a single bond of a OE+.is cleaved?A. The more abundant observable fragment will have a lower ionization energy B. The fragment that retains the unpaired electron will have a higher ionization energyC. Which fragment is larger may depend on the structure of the molecular ionD. A & B E. A & B & C sometimes9Clicker Question 2• Related to Stevenson's Rule what is true when a single bond of a OE+.is cleaved?A. The more abundant observable fragment will have a lower ionization energy B. The fragment that retains the unpaired electron will have a higher ionization energyC. Which fragment is larger may depend on the structure of the molecular ionD. A & B E. A & B & C sometimesFor the following structure, which mass spectrum would you expect to see?M+EEEEMass (Odd/Even)OOEA.C.Mass (Odd/Even)M+EEOED.Mass (Odd/Even)OEEEM+M+Mass (Odd/Even)B.EOOOEEEEEE10For the following structure, which mass spectrum would you expect to see?M+EEEEMass (Odd/Even)OOEA.C.Mass (Odd/Even)M+EEOED.Mass (Odd/Even)OEEEM+M+Mass (Odd/Even)B.EOOOEEEEEEFor the following molecule, what is the most likely fragment & how is it formed9177A109105BCD11For the following molecule, what is the most likely fragment & how is it formed105C++What unusual element does this molecule contain? What is a likely molecular formula?158785139A. Germanium (Ge2H10)B. Germanium (C6H12Ge)C. Selenium (C6H6Se)D. Selenium (Se2) E. No unusual elements, it’s Bromine (C4H3BrN2)12What unusual element does this molecule contain? What is a likely molecular formula?158785139A. Germanium (Ge2H10)B. Germanium (C6H12Ge)C. Selenium (C6H6Se)D. Selenium (Se2) E. No unusual elements, it’s Bromine (C4H3BrN2)Unknown Spectrum 1• 10 largest peaks:333 999 | 276 306 | 295 268 | 314 261 | 257 161 |238 76 | 138 34 | 157 27 | 330 7 | 352 3 |( i lib) U i h fl id130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360050100138157238257276295314333FFFFFFU13Unknown Spectrum 1• 10 largest peaks:333 999 | 276 306 | 295 268 | 314 261 | 257 161 |238 76 | 138 34 | 157 27 | 330 7 | 352 3 |( i lib) U i h fl id130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360050100138157238257276295314333FFFFFFUUnknown Spectrum 214Unknown Spectrum 2• 10 largest peaks:192 999 | 190 773 | 111 653 | 75 359 |


View Full Document

CU-Boulder CHEM 5181 - Review Questions

Download Review Questions
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view Review Questions and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view Review Questions 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?