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Chemistry LibreTexts

In-class Questions

You are likely familiar with a device called a centrifuge where a sample is put into a suitable holder and spun. The spinning creates a centrifugal force that is greater than gravity, with the result that the centrifugal force causes particles in the sample holder to settle out.

Q1. What are the variables that influence the settling of a particle in a centrifuge?

Q2. What does the name ultracentrifuge imply?

Q3. Suppose you wanted to separate molecules or particles using an ultracentrifugation procedure. What variables could you alter that would allow you to complete the separation?

Q4. How could you use the speed of the centrifuge or time that the sample has been allowed to spin to perform a separation of several different components of the mixture?

A second variable is the density of the solvent in the centrifuge tube.

Q5. Can you think of a procedure based on solvent density that could be used to separate several different components of a mixture in an ultracentrifuge?

Q6. Can you think of a procedure for generating a density gradient in a centrifuge tube?