FREE MCAT AND STUDY GAMES ABOUT MCAT LAB

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FREE MCAT AND STUDY GAMES ABOUT MCAT LAB

TECHNIQUES EXAM QUESTIONS

Qs and Ans Expert- Explanation

This Exam contains:

-Guarantee passing score -21 Questions and Answers -format set of multiple-choice -Expert- Explanation

Question 1: Ion exchange chromatography

Answer:

gravity filtration with ionic resins, or salts, where the + charged will flow through and replace the N for example; what does not stick, neutral and - out first; pI value of importance; pI values above pH first to elute

Question 2: affinity chromatography

Answer:

stationary phase solid resin, like with Ab; binding with Ab goes gravity bottom; no centrifuge using beads magenetized; commercialized specificity; N/C affinity tag

Question 3: liquid-liquid extraction

Answer:

shaken and sepa like like (polar-polar eg); salt from base+acid in aqueous solution;WB&COOH=anionic salt; phenols w/ NaOH diluted; NaHCO3 no phenol yes COOH

Question 4: distillation

Answer:

breaking bonds; making bonds; BP

Question 5: Column chromatography

Answer:

SiO2 gel gravity filtration with polar reacting with gel/TLC plate; least polar comes out first

Question 6: spin-spin splitting

Answer:

H NMR; Hs not same group interact; protons in field interact with molecule proton; n + 1 & n=neighboring Hs; if 2 neighboring Hs interfere then 3 splits; singlet for 0 doublet for 1, triplet, quartet, quintet, sextet

Question 7: UV Visible spec

Answer:

transition metal d orbital & conjugation pi bonds; wavelength related to amt of conjugation; absorption and emission opposite red-green;orange-blue;vio-yell

Question 8: reverse phase HPLC

Answer:

nonpolar is silica gel binds nonpolar; mobile is polar

Question 9: principle of extraction

Answer:

salts are preferred for aqueous phase

Question 10: IR spec

Answer:

wavelength 2.5 to 20um; excited vibration; wavenumber is 1/wavelength=v/c; E=hv; RCOR 1700; C=C 1650; OH 3600-3200; RCCR 2260-2100; CH 3300-2700; N low O

Question 11: gas chromatography

Answer:

mobile gas phase & stationary liquid phase; volatility

Question 12: Fractional distillation

Answer:

column packed with wire/beads/cotton; vapor impurities at bottom; pure at top

Question 13: spectroscopy, general

Answer:

ground state to excited state to ground =emission & record

Question 14: size exclusion chromatography

Answer:

porous polymer beads; small travel more distance end up last

Question 15: H NMR spec, general

Answer:

equivalent Hs

Question 16: polar stationary phase of TLC

Answer:

solid-liquid with SiO2 absorbent; developing/running

Question 17: High Performance Liquid Chromatography (HPLC)

Answer:

high pressure forces mobile through stationary = efficient speed, no gravity; chromatogram; silica gel

Question 18: Simple distillation

Answer:

impurities miniscule; BP

Question 19: NMR integration

Answer:

area under curve related to number of Hs causing the spike

Question 20: thin layer chromatography

Answer:

polarity & capillary action; results UV light maybe & Rf = substance move/solvent final move

Question 21: Mass spec

Answer:

high vacuum ionization; magnetic field & flight path change; r=mv/qB; abundance y axis & M/e x axis; good for isotopes; Br/Cl