Pure Substances and Melting Point Quiz
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Questions and Answers

What is the purpose of a formulation?

  • To design useful products with carefully measured amounts of chemicals (correct)
  • To test the quality of the mixed substances
  • To separate mixtures of soluble substances
  • To create a random mixture of chemicals

    • Why is paper chromatography used?

  • To separate mixtures of soluble substances and identify the substances present (correct)
  • To create mixtures of soluble substances
  • To measure the melting point of a pure substance
  • To test the quality of a substance

    • Why do pure substances have a sharp melting point?

  • Because they are quality tested
  • Because they are not mixed with other substances (correct)
  • Because they have carefully measured amounts of chemicals
  • Because they contain impurities that affect the melting point

    • Which types of substances are often separated using paper chromatography?

    <p>Colored substances like food colorings and inks</p> Signup and view all the answers

    What can be inferred about the chemicals in a formulation?

    <p>They are carefully measured and have specific purposes in the formulation</p> Signup and view all the answers

    What is the common characteristic of substances separated using paper chromatography?

    <p>They have varying melting points</p> Signup and view all the answers

    What is the mobile phase in chromatography?

    <p>The solvent that moves through the paper</p> Signup and view all the answers

    How can a paper chromatogram distinguish between pure and impure substances?

    <p>A pure substance produces one spot, while an impure substance produces two or more spots</p> Signup and view all the answers

    What can be used to identify unknown chemicals in chromatography?

    <p>Rf values</p> Signup and view all the answers

    What happens if oxygen is present in a test tube?

    <p>A glowing splint relights when held inside</p> Signup and view all the answers

    How can hydrogen be identified in a test tube?

    <p>A lighted splint held near its mouth ignites with a squeaky pop</p> Signup and view all the answers

    What does carbon dioxide not support?

    <p><strong>Combustion</strong></p> Signup and view all the answers

    What are the two phases that chromatography relies on?

    <p><strong>Mobile phase</strong> and <strong>stationary phase</strong></p> Signup and view all the answers

    What is used to calculate Rf values in chromatography?

    <p><strong>Distance traveled by the spot / Distance traveled by the solvent</strong></p> Signup and view all the answers

    What does a lighted splint do when hydrogen is present?

    <p><strong>Ignites with a squeaky pop</strong></p> Signup and view all the answers

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