Preview Questions Chemical Researcher | Role Specific Skill

Question 1: In Fourier Transform Infrared Spectroscopy (FTIR), how is the sample's molecular structure determined?

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By measuring the absorbance of infrared light at different wavelengths and identifying functional groups

By calculating the peak intensity ratios

By monitoring the emission of light after excitation

By measuring the change in refractive index with different frequencies

Question 2: What is the main principle behind the use of NMR (Nuclear Magnetic Resonance) spectroscopy in structural analysis?

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It measures the vibration of chemical bonds in a molecule

It detects the interaction between magnetic nuclei in a magnetic field

It quantifies the amount of light absorbed by a sample

It separates molecules based on their size and charge

Question 3: How do you account for potential sources of error in an experimental setup in chemical research?

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By not measuring the input variables too rigorously

By ignoring minor variations and focusing on the desired outcome

By conducting a thorough risk assessment and implementing controls for each variable

By assuming all experimental conditions remain constant

Question 4: What role do the reference and sample beams play in a Fourier-transform infrared (FTIR) spectrometer?

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The sample beam is blocked during analysis to measure baseline noise

The reference beam is used to measure the sample's response, while the sample beam is directed through the sample for comparison

The reference beam is used for calibration, while the sample beam measures the absorbance of light

Both beams measure the intensity of light that passes through the sample

Question 5: How does solid-phase microextraction (SPME) work in sample preparation, and what are its advantages in the analysis of volatile compounds?

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SPME uses a solid adsorbent to extract analytes directly from the sample, providing fast and sensitive analysis with minimal sample handling

SPME is useful only for non-volatile compounds

SPME uses a liquid solvent to extract analytes from samples

SPME cannot be used for chemical analysis

Question 6: In Nuclear Magnetic Resonance (NMR) spectroscopy, what does the chemical shift of a nucleus indicate?

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The temperature of the sample

The relative abundance of isotopes in the sample

The magnetic field strength applied to the sample

The electronic environment surrounding the nucleus