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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. Do not “Google” the answers: use the text you were given to find the answers to the questions.

Define the following terms:

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

Answer the following questions with grammatical and complete English sentences.

  1. What is the difference between an atom and an element?
  2. What is the difference between a molecule and a compound?
  3. What do the words monatomic and diatomic mean? Give examples of chemical formulas for substances to which these descriptions apply.
    Monatomic formulas                          Diatomic formulas
  4. To be diatomic, does a substance have to be an element or could a diatomic substance be a compound? Explain and give examples.
  5. Both compounds and mixtures are made of atoms of different types. What are the two key differences between them?
  6. What are the characteristics of a homogeneous mixture? Give some examples from your own experience of making or using homogeneous mixtures.
  7. It isn’t always easy to tell the difference between mixtures that are homogeneous and mixtures that are heterogeneous. If you had eyes that could see things microscopic or molecular in size it would be a lot easier. Why?
  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 pair. 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. In the space below or at right draw the following models:
    1. A gaseous element made of diatomic molecules, 2. A liquid compound, 3. A solid compound, 4. A liquid mixture of Na+ ions, Cl ions, and water, and 5. A gaseous mixture of oxygen, nitrogen, and argon gases
    1. 









    2.  3.  4.  5. 
These questions can be answered after reading notes about the Classification of Matter
and the Modeling the Molecular Level Activity
See also: Phases of Matter Homework
Phases of Matter with the PhET simulator
After this basic review sheet try the Writing for Understanding activity.
Last updated: Aug 20, 2019
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