Lesson 7 Conclusion

Did you know that the RCMP only has three forensic labs in all of Canada and one is located in Edmonton?


B7.22 Vial of unknown powder
Understanding simple tests to help determine the identity of an unknown substance is crucial in forensic investigations.

In this lesson, you learned how to identify ionic, molecular, acidic, and basic compounds based on their properties. You also learned how to predict the solubility of ionic compounds. As well, you studied the special properties of water that are related to its bonding.

  Problem Solving Activity

Mystery Solution Analysis
In this activity, you are going to take the information you have learned about the properties of ionic, molecular, acidic, and basic compounds and use it to identify four unlabelled containers. Each beaker contains a clear solution. Using litmus paper and a conductivity apparatus, determine which beaker contains each of the following substances: calcium bromide, methanol, hydrofluoric acid, and potassium hydroxide.

Click on the data tab to continue.
Unknown
Conductivity Results
Litmus Results
1
2
3
4

Click on the analysis tab to answer the analysis questions.
  1. Write the chemical formula for each of the compounds.

    calcium bromide—CaBr2
    methanol—CH3OH
    hydrofluoric acid—HF
    potassium hydroxide—KOH
  2. Based on the chemical formula, classify each of the compounds as being ionic neutral, molecular neutral, acidic, or basic.

    calcium bromide—ionic neutral
    methanol—molecular neutral
    hydrofluoric acid—acidic
    potassium hydroxide—basic
  3. Based on the data and the classifications in question 2, match each chemical compound with its correct unknown sample.

    calcium bromide—3
    methanol—2
    hydrofluoric acid—1
    potassium hydroxide—4