Difficulty: Easy
Correct Answer: separation of isotopes based on their density or molecular weights difference.
Explanation:
Introduction / Context:
Ultracentrifuges generate extremely high centrifugal fields by spinning at very high speeds (often approaching 100000 rpm). Such fields enable separations that rely on minuscule density or mass differences—well beyond the reach of standard industrial centrifuges.
Given Data / Assumptions:
Concept / Approach:
At ultrahigh g-levels, sedimentation velocities become large enough for species with very small density differences (or molecular weight differences) to separate in reasonable times. This is the basis for isotopic enrichment and fractionation of macromolecules. Other listed duties (latex concentration, cream separation, dewaxing) require far lower g-forces and are handled by conventional centrifuges or process-specific equipment.
Step-by-Step Solution:
Identify which duty needs extreme g: isotope/density fine differences.Map to equipment: ultracentrifuge is designed exactly for that.Exclude duties manageable by standard centrifuges (cream separation, latex) or by filtration/solvent-based dewaxing processes.
Verification / Alternative check:
Historical and modern applications of ultracentrifuges include isotope separation and macromolecular characterization (proteins, nucleic acids), validating the selection.
Why Other Options Are Wrong:
Latex and cream separations: achieved at modest speeds using disc-stack or bowl centrifuges.Dewaxing: typically solvent-based with filtration or chill-settling—does not rely on ultrahigh g.
Common Pitfalls:
Assuming “higher speed is always better.” Process needs determine equipment; ultracentrifuges are overkill for common industrial separations.
Final Answer:
separation of isotopes based on their density or molecular weights difference.
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