Chemical Analysis & Techniques Flashcards
7 cards from real CPC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Chemical Analysis & Techniques flashcards as text
Which property of X-ray fluorescence (XRF) makes it useful for elemental analysis?
Answer: Each element emits characteristic secondary X-rays when excited
When primary X-rays excite atoms, each element emits characteristic fluorescent X-rays at wavelengths unique to that element, enabling identification and quantification.
In HPLC, what is the difference between isocratic and gradient elution?
Answer: Isocratic maintains constant mobile phase composition; gradient changes it over time
Isocratic elution uses a constant mobile phase composition throughout the run, while gradient elution systematically changes solvent strength to improve separation of complex mixtures.
What analytical technique uses the principle of inductively coupled plasma to excite atoms for emission detection?
Answer: ICP-OES
ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) uses an argon plasma at ~6000-10000 K to excite atoms, which then emit characteristic light at element-specific wavelengths.
In titration analysis, what is the equivalence point?
Answer: The point where moles of titrant exactly equal moles of analyte
The equivalence point is where the amount of titrant added is stoichiometrically equal to the analyte, representing complete reaction.
Which spectroscopic technique provides information about the functional groups in an organic molecule through molecular vibrations?
Answer: Infrared (IR) spectroscopy
IR spectroscopy identifies functional groups based on characteristic absorption frequencies of molecular bond stretching and bending vibrations.
What is the Van Deemter equation used to describe in chromatography?
Answer: Factors contributing to band broadening and plate height as a function of flow rate
The Van Deemter equation describes how plate height (H) varies with mobile phase velocity, accounting for eddy diffusion (A), longitudinal diffusion (B), and mass transfer (C) terms.
In coulometry, what is the fundamental principle used for quantitative analysis?
Answer: Faraday's law relating charge passed to moles of analyte
Coulometry uses Faraday's law, where the total electrical charge (coulombs) passed is directly proportional to the moles of analyte oxidized or reduced.