8th Grade First Semester Mid-term Exam

85 Questions | Total Attempts: 190

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8th Grade First Semester Mid-term Exam


Questions and Answers
  • 1. 
    The term ____________ is applied to any substance that cannot be made simpler without changing its chemical make-up.
    • A. 

      Element

    • B. 

      Atom

    • C. 

      Molecule

    • D. 

      Substance

  • 2. 
    What forms when one substance dissolves another?
    • A. 

      Solution

    • B. 

      Solvent

    • C. 

      Dissolution

    • D. 

      Solute

  • 3. 
    A substance that dissolves another substance is called a ____________?
    • A. 

      Solvent

    • B. 

      Solution

    • C. 

      Dissolution

    • D. 

      Solute

  • 4. 
    Identify the property of water that allows a water strider insect to walk on the water.
    • A. 

      Surface Tension

    • B. 

      Polarity

    • C. 

      Capillary Action

    • D. 

      Specific Heat

  • 5. 
    Water is a universal solvent because:
    • A. 

      Water is polar and can dissolve more substances than any other liquid

    • B. 

      Solutes are not polar molecules

    • C. 

      Water is made up hydrogen and oxygen atoms

    • D. 

      Water has a neutral pH

  • 6. 
    What is adhesion?
    • A. 

      Waters ability to stick to other materials

    • B. 

      Waters ability to stick to itself

    • C. 

      Covalent bonds in water

    • D. 

      Capillary Action

  • 7. 
    What is an atom?
    • A. 

      The smallest part of an element that is a basic unit of matter

    • B. 

      The unit measure of an element

    • C. 

      Elements that make up molecules

    • D. 

      Neutrons in the nucleus

  • 8. 
    How do soap micelles work?
    • A. 

      Micelles are clusters of soap molecules that move to the surface so that their polar hydrophilic ends are pointed toward the water and the non-polar hydrophobic ends stick out. The bubbles ‘sit’ on the surface of the water, because the surface of the bubble is covered with the non-polar (hydrophobic) layer.

    • B. 

      Micelles cluster on the hydrophobic ends of water molecules so that their polar heads can trap oil and dirt.

    • C. 

      Micelles cluster on the hydrophilic ends of water molecules so that their nonpolar tails can trap oil and dirt.

    • D. 

      Micelles are clusters of soap molecules that ‘sit’ below the surface of the water so that their hydrophobic tails stick into the water solution.

  • 9. 
    Identify the statement that is correct about the number of protons and electrons in an atom:
    • A. 

      The number of protons and the number of electrons in an atom are always equal.

    • B. 

      The number of protons is always greater than the number of electrons in an atom.

    • C. 

      The number of protons is always less than the number of electrons in an atom.

    • D. 

      The number of protons and electrons equals the mass of an atom.

  • 10. 
    What is a valence electron?
    • A. 

      Ionically bonded electrons

    • B. 

      Electrons in the outer most cloud of an atom

    • C. 

      A negatively charge ion

    • D. 

      A positively charge ion

  • 11. 
     Why do hydrogen atoms usually exist as molecules, H2?
    • A. 

      Hydrogen has an atomic number of one and is unsatisfied when the outermost orbital is unfilled. A hydrogen molecule of two hydrogen atoms is more stable than two individual hydrogen atoms

    • B. 

      Hydrogen has an atomic number of two and does not need to share

    • C. 

      Hydrogen usually combines with other atoms to form covalent bonds

    • D. 

      Hydrogen has one proton and is in search of one neutron

  • 12. 
    What is an emulsion?
    • A. 

      A mixture of liquids that do not dissolve in each other. One liquid is suspended within the other liquid.

    • B. 

      When one liquid repels another and is neutral.

    • C. 

      When a solute dissolves in a solvent.

    • D. 

      When a liquid solidifies.

  • 13. 
    What is electronegativity?
    • A. 

      How many electrons are in a valence.

    • B. 

      The strength of an atoms' electrons.

    • C. 

      The electrical charge of a polar molecule.

    • D. 

      The exchange of electrons in ionic bonding.

  • 14. 
     This diagram represents H2.  What does the Hsymbol mean?
    • A. 

      The H2 symbol represents two atoms of Hydrogen.

    • B. 

      The H2 symbol represents a Hydrogen atom.

    • C. 

      The H2 symbol represents a water molecule.

    • D. 

      The H2 symbol represents an ionic bond.

  • 15. 
     In this diagram, the e- represents:
    • A. 

      The e- represents the covalent Hydrogen electron bond in this Hydrogen molecule.

    • B. 

      The pair of e- represents the double covalent Hydrogen electrons in the Hydrogen molecule.

    • C. 

      The pair of e- represents the ionic Hydrogen electrons in this Hydrogen molecule.

    • D. 

      The e- represents a single shared Hydrogen electron in this Hydrogen molecule.

  • 16. 
    Why are Hydrogen covalent bonds non-polar?
    • A. 

      Hydrogen bonds are non-polar because electrons in the bonds between identical atoms (H-H) are shared uniformly. This means electrons spend equal amounts of time around each atoms center.

    • B. 

      Hydrogen bonds are non-polar because protons in the bonds between identical atoms (H-H) are shared uniformly. This means electrons spend equal amounts of time around each atoms center.

    • C. 

      Hydrogen bonds are non-polar because protons in the bonds between identical atoms (H-H) are not shared uniformly. This means electrons do not spend equal amounts of time around each atoms center.

    • D. 

      Hydrogen bonds are non-polar because protons and electrons in the atom of identical atoms (H-H) are shared uniformly. This means electrons do not spend equal amounts of time around each atoms center.

  • 17. 
       The water and air pressure lab:If the lab were done while climbing Mt. Everest, as altitude increases what happens?
    • A. 

      As altitude increases, air becomes less dense and the air pressure decreases. The water would not shoot out of the container.

    • B. 

      As altitude increases, air becomes more dense and the air pressure decreases. The water would not shoot out of the container.

    • C. 

      As altitude increases, air becomes more dense and the air pressure increases. The water would shoot out of the container farther than in the classroom.

    • D. 

      As altitude increases, air becomes less dense and the air pressure increases. The water would shoot out of the container farther than in the classroom.

  • 18. 
    What did Ben Franklin's experiment with nonpolar substances accurately measure?
    • A. 

      Ben Franklin accurately measured the thickness of a single-molecule thick layer of olive oil on water.

    • B. 

      Ben Franklin accurately measured the pollution in the pond water caused by the olive oil.

    • C. 

      Ben Franklin accurately measured the change in surface tension when olive oil was added to the pond.

    • D. 

      Ben Franklin accurately measured the area of underwater visibility created by altered surface tension when oil was added to water.

  • 19. 
    Which force is capillary action related to?
    • A. 

      Adhesion

    • B. 

      Cohesion

    • C. 

      Surface Tension

    • D. 

      Polarity

  • 20. 
    Identify: a substance that is being dissolved is a _________________
    • A. 

      Solute

    • B. 

      Solution

    • C. 

      Solvent

    • D. 

      Insoluble

  • 21. 
    Celery test: What property of water does the celery test model?
    • A. 

      Capillary Action

    • B. 

      Polarity

    • C. 

      Surface Tension

    • D. 

      Specific Heat

  • 22. 
    Choose the correct term to fill in the blank.The Earth's __________ pulls on air, and this pull, or "pressure" of air, is called atmospheric pressure.
    • A. 

      Gravity

    • B. 

      Density

    • C. 

      Volume

    • D. 

      Air Pressure

  • 23. 
    In the water pressure lab:What do you predict would happen to the water coming out of the container if the container holes were larger? 
    • A. 

      If the holes were larger, the volume of water flowing is greater, but slower with less pressure.

    • B. 

      If the holes were larger, the volume of water flowing is less, but faster with more pressure.

    • C. 

      If the holes were larger, the volume of water flowing is greater, faster and with more pressure.

    • D. 

      If the holes were larger, the volume of water flowing is greater, faster and with less pressure.

  • 24. 
    In the water pressure labs:What would you predict about the water coming out of the container if the container holes were made smaller? 
    • A. 

      Water comes out of the container faster, is under greater pressure and there is less volume of water in the flow.

    • B. 

      Water comes out of the container faster, is under less pressure and there is greater volume of water in the flow.

    • C. 

      Water comes out of the container slower, is under greater pressure and there is less volume of water in the flow.

    • D. 

      Water comes out of the container slower, is under less pressure and there is less volume of water in the flow.

  • 25. 
    Floating Paper Clip:Why does adding liquid detergent to the water change how the paper clip floats?
    • A. 

      It breaks the polarity and therefore the surface tension

    • B. 

      Liquid detergent is not soluble

    • C. 

      It changes the pH

    • D. 

      It changes the specific heat

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