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Homework: Classification of Matter

Answer all items using a complete sentence in your best, most professional writing style. Write definitions in such a way that someone your age who is not taking chemistry would understand it.

Define the following terms:

  1. Atom
  2. Molecule
  3. Particle
  4. Element
  5. Compound
  6. Ionic Compound
  1. Molecular Compound
  2. Homogeneous Mixture
  3. Heterogeneous Mixture
  4. Solid
  5. Liquid
  6. Gas

Answer the following questions with grammatical and complete English sentences.

  1. Can a solid be easily compressed? How about a liquid? A gas? For each case, explain your answer.
  2. Do molecules change size or shape when a substance changes phase (from solid to liquid to gas)? Explain.
  3. Why are gases so much lower in density than liquids?
  4. What is the relationship between temperature and the phase of matter?
  5. Can a gas be compressed so much it becomes a liquid? A solid? Explain.
  6. What is the difference between an atom and an element?
  7. What is the difference between a molecule and a compound?
  8. Identify the following items as an element, compound, or mixture. Their chemical formulas are given to help you out.
    1. Sugar (C6H12O6)
    2. Phosphorous (P4)
    3. Battery Acid (H2SO4)
    4. Air (N2 & O2 & Ar & CO2)
    5. Oxygen (O2)
    6. Milk (C12H22O11 & H2O & C50H102O3…)
    1. Gold (Au)
    2. Drain Cleaner (Al & NaOH)
    3. Sodium (Na)
    4. Water (H2O)
    5. Salt Water (NaCl & H2O)
    6. Brass (Zn & Cu)

  9. Pick the true statement from each of the following pairs. For each incorrect sentence, explain why it is wrong.
      1. Two or more atoms held together with bonds make up a molecule.
      2. Two or more substances mixed together make up a compound.


      1. Pure substances are made of just one type of atom or two or more types of atom in a specific ratio.
      2. Pure substances are made of only one type of atom.


      1. At least two types of atoms are required to make a compound.
      2. At least two types of atoms are required to make a molecule.


      1. Mixtures can be made of two elements, two compounds or an element and a compound.
      2. Compounds can be made of two elements, two mixtures, or an element and a mixture.


  10. Ionic compounds are made of at least two different ions: one positive ion and one negative ion. Solid ionic compounds form a network of ions with opposite charges alternating with one another. For a compound such as CaCl2 a small piece of the material may have hundreds, thousands, or millions of atoms but always there are twice as many chlorine atoms as calcium atoms. Some say ionic compounds do not form molecules. Based on this description, is it true to say there are no molecules of an ionic compound? Explain.
These questions can be answered after reading notes about the Classification of Matter
After this basic review sheet try the Writing for Understanding activity.
And the Modeling the Molecular Level Activity
Last updated: Aug 27, 2015
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