Name: ________________________________ Date:_________________ Block: ______
IPS LABORATORY EXPERIMENT
– COMPARING COVALENT AND IONIC COMPOUNDS –
Background Information
Compounds are either covalent or ionic, depending on the nature of the forces that
hold them together. In ionic compounds, the force of attraction is between oppositely
charged ions. This attraction is called an ionic bond. In covalent compounds, atoms are
held together by an interaction between adjacent nuclei and shared electrons. These
different forces account for many of the properties of ionic and covalent compounds,
such as degree of volatility (ability to turn into a gas) and solubility (ability to dissolve).
In this investigation you will examine the properties of a representative ionic
compound, sodium chloride, and a representative covalent compound, paraffin. The
properties studied will be volatility, ease of melting, and solubility in water.
Purpose
Compare and contrast the properties of ionic and covalent compounds.
Materials
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sodium chloride
paraffin
two crucibles
aluminum foil
clay triangle
Bunsen burner
flint
two test tubes
ring stand with ring
safety goggles
apron
Procedure
1. Put on safety goggles and apron.
2. Carefully smell each compound. If you can detect an
odor, assume that the compound has a high volatility.
If there is no smell, assume the compound has a low
volatility. Record your observations in the data table.
3. Wrap the crucibles with aluminum foil. Place a small
amount of each substance in separate crucibles (See
Figure 1) and heat with the Bunsen burner. Time
how long it takes to melt each substance. As soon as
each substance begins to melt turn off the flame.
Record your observations in the data table.
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Name: ________________________________ Date:_________________ Block: ______
4. Half fill two test tubes with room temperature water. Put a small amount of each
substance in separate test tubes. Place your thumb over the top of each test tube
and shake. If the substance dissolves record that the substance is soluble. If the
substance does not dissolve record that the substance is insoluble.
5. Clean up. Do not put paraffin in the sink, but you may put it in the trash. Sodium
chloride may be placed in the trash or sink. When your station is clean, raise your
hand to be dismissed. Remember, do not remove your apron or safety goggles
until you are dismissed from your lab station.
Observations
DATA TABLE
Substance
Volatility
Melting Time
Solubility
Sodium chloride
Paraffin
1. Which compound was more volatile? ___________________________________
2. Which compound melted more quickly? _________________________________
3. Which compound dissolved more easily in water? _________________________
Analysis and Conclusion
1. Explain why the type of bond could determine the volatility of a substance.
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2. Does the strength of a bond have anything to do with the time it takes to melt a
substance? Explain.
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Name: ________________________________ Date:_________________ Block: ______
3. Water is a polar molecule. This means that it has a negatively charged side and a
positively charged side. Predict which substance will dissolve more easily, an
ionic compound or a non-polar covalent compound.
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Critical Thinking and Application
1. What does your data tell you about the melting points of ionic and covalent
compounds? How can you tell?
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2. Which do you think would be more dangerous near an open flame? Why?
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3. Which type of compound would you expect to have a higher boiling point? Why?
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4. Suppose you had a mixture of an ionic compound and a covalent compound. How
would you separate the two compounds?
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Name: ________________________________ Date:_________________ Block: ______
5. What was the purpose of this lab?
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6. What procedure was used to fulfill the purpose of this lab?
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7. What were the results from the lab?
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