Separation Techniques Quiz
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Questions and Answers

What is the main purpose of filtration?

  • Remove small solid particles from a mixture
  • Separate a solid from a liquid (correct)
  • Separate mixtures of liquids with different boiling points
  • Remove impurities from two solids
  • Why is vacuum filtration used instead of gravity filtration?

  • Liquid particles are too small and block the filter paper
  • Solid particles are too small and block the filter paper (correct)
  • Solid particles are too large to pass through the filter paper
  • Liquid particles are too large to pass through the filter paper
  • Distillation is effective because:

  • Components of the mixture are in the same physical state
  • Liquids in the mixture have different boiling points (correct)
  • Solids in the mixture have different melting points
  • Molecules in the mixture have different colors
  • Recrystallization is primarily used to:

    <p>Remove impurities from two solids</p> Signup and view all the answers

    Chromatography separates compounds based on differences in their:

    <p>Physical or chemical properties</p> Signup and view all the answers

    Gravity filtration differs from vacuum filtration in that gravity filtration relies on:

    <p>The force of gravity to pull the liquid through the filter paper</p> Signup and view all the answers

    What is the primary factor that leads to the separation of compounds in gas chromatography?

    <p>Affinity for the stationary phase</p> Signup and view all the answers

    Which compound is expected to be retained the longest in gas chromatography?

    <p>Compound 11</p> Signup and view all the answers

    In gas chromatography, which detector burns all organic compounds and detects current?

    <p>Flame ionization detector</p> Signup and view all the answers

    What is the purpose of the liquid solvent or mixture of solvents in liquid chromatography?

    <p>Carry the sample through the chromatographic column</p> Signup and view all the answers

    Which component of a chromatograph contains the stationary phase and interacts with sample components?

    <p>Column</p> Signup and view all the answers

    What property is used for separation in liquid chromatography?

    <p>Polarity, size, or charge</p> Signup and view all the answers

    What is the purpose of wetting the filter paper with a small amount of solvent or solution before pouring the liquid mixture into the Büchner funnel?

    <p>To create a seal and improve filtration efficiency</p> Signup and view all the answers

    What role does turning on the vacuum source play in the filtration process described?

    <p>It creates a pressure difference that pushes liquid through the filter paper</p> Signup and view all the answers

    Why are different boiling points of components important for effective distillation?

    <p>To ensure complete separation of components</p> Signup and view all the answers

    How does ethanol's lower boiling point compared to water relate to its intermolecular forces?

    <p>Ethanol has weaker intermolecular forces than water</p> Signup and view all the answers

    What is the primary function of distillation in separating liquid mixtures?

    <p>To separate components based on their different boiling points</p> Signup and view all the answers

    How does strong hydrogen bonding contribute to higher boiling points in liquids?

    <p>By requiring more energy to transition to gas phase</p> Signup and view all the answers

    What is the main purpose of a UV-Visible detector in liquid chromatography?

    <p>Measures the absorbance of ultraviolet light to facilitate separation based on size</p> Signup and view all the answers

    In Size Exclusion Chromatography, why do smaller molecules take longer paths through the column?

    <p>They cannot enter the pores of the stationary phase</p> Signup and view all the answers

    What is the role of the mobile phase in liquid chromatography?

    <p>Facilitates movement of sample components through the column</p> Signup and view all the answers

    Why do larger molecules move more quickly through a Size Exclusion Chromatography column?

    <p>They cannot enter the pores of the stationary phase</p> Signup and view all the answers

    How are components separated in liquid chromatography?

    <p>By differential interaction with stationary and mobile phases</p> Signup and view all the answers

    Which type of liquid chromatography is specifically used to separate biomolecules based on their size?

    <p>Size Exclusion Chromatography</p> Signup and view all the answers

    Why do larger molecules elute first in chromatography?

    <p>They enter the non-porous path and move more quickly.</p> Signup and view all the answers

    What happens when a salt and sand mixture is combined with water?

    <p>Salt dissolves while sand remains insoluble.</p> Signup and view all the answers

    What is the main principle behind the separation of molecules in chromatography?

    <p>Differences in size</p> Signup and view all the answers

    Why are smaller molecules retained for a longer time in chromatography?

    <p>They enter the pores and have an extended path.</p> Signup and view all the answers

    What is the purpose of the detector in chromatography?

    <p>To record signals from eluting components</p> Signup and view all the answers

    Study Notes

    Filtration and Its Variants

    • Main purpose of filtration is to separate solids from liquids.
    • Vacuum filtration uses suction to accelerate the filtration process, making it faster than gravity filtration.
    • Gravity filtration relies on the force of gravity to pull the liquid through the filter, which can be slower than vacuum filtration.

    Distillation

    • Distillation is effective because it separates components based on differences in boiling points.
    • Different boiling points are crucial to ensure effective separation during distillation.
    • Ethanol has a lower boiling point than water due to weaker intermolecular forces, facilitating easier evaporation during distillation.
    • The primary function of distillation is to purify liquid mixtures by separating components.

    Chromatography Techniques

    • Chromatography separates compounds based on differences in their affinities for the stationary and mobile phases.
    • In gas chromatography, the separation of compounds is primarily influenced by their vapor pressures.
    • Larger hydrocarbons typically have lower vapor pressures and are expected to be retained longer in gas chromatography.
    • A flame ionization detector in gas chromatography burns organic compounds to detect electrical current.

    Liquid Chromatography

    • Purpose of the liquid solvent is to dissolve the sample and carry it through the chromatographic system.
    • The stationary phase exists within the chromatograph, interacting with sample components and facilitating separation based on various properties.
    • Property used for separation in liquid chromatography can include polarity, size, or charge.
    • Wetting the filter paper with solvent minimizes the loss of sample during filtration.
    • Turning on the vacuum source enhances filtration speed by creating a pressure differential.

    Size Exclusion Chromatography (SEC)

    • In Size Exclusion Chromatography, smaller molecules take longer paths due to their ability to enter pores in the stationary phase, thereby increasing their travel time.
    • Larger molecules move more quickly through the column because they are excluded from the pores.
    • SEC specifically separates biomolecules based on size.

    General Chromatography Principles

    • In chromatography, components are separated based on their differing interactions with the stationary and mobile phases.
    • Larger molecules elute first as they do not interact strongly with the stationary phase and can flow through the columns more freely.
    • Smaller molecules are retained longer due to their interactions with the stationary phase or being trapped in small pores.

    Additional Details

    • When a salt and sand mixture is combined with water, the salt dissolves while the sand remains undissolved, illustrating the principle of solubility in chromatography.
    • The purpose of the detector in chromatography is to quantify and identify the separated components as they elute from the column.

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    Description

    Test your knowledge on separation techniques such as filtration, distillation, recrystallization, and chromatography. Learn how these methods use physical or chemical differences to separate compounds based on their properties.

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