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Properties of Matter: Investigation 4 –










By observing a sample of matter and measuring its chemical and physical properties, we gradually acquire enough information to characterize it and distinguish it from other kinds of matter. This is the first step in the development of chemical science, in which interest is focused on specific types of matter.


Biochemists study the chemical composition of living things. A biochemist might develop a vaccine to prevent a new strain of flu or new biofuels that could provide an alternative source of energy.


This Investigation is designed to help you to answer the following Focus Questions: 

  • Can compounds composed of the same elements have a similar or dissimilar pH? 
  • Do all liquid compounds have the same pH? Why or why not? 
  • Do all solid compounds have the same pH? Why or why not? 


Read the Background(s) in the Investigation in your SDR. When you have finished, discuss the following concepts as a class:

  • pH is a property of compounds used to describe whether a compound is an acid, base, or neutral substance.
  • The pH scale extends from 1 to 14.
  • Substances with a pH less than 7 are considered acidic. 
  • Substances with a pH greater than 7 are considered basic.
  • Substances with a pH of 7 are neutral.



The following Key Term is introduced in the Investigation Background(s). It should be used, as appropriate, during everyday classroom discourse.

  • pH



  • In this Investigation, you will explore another property of compounds – pH
  • pH is a chemical property of substances. 
  • Based on pH, substances are described as acidic, neutral, or basic.
  • pH is often a property used to classify or categorize compounds.
  • Complete the Recall section in your SDR.
  • Play the video below. Remember to follow along in your SDRs and make any notes that you think might be helpful.

Note: The purpose of the video below is to allow you to anticipate the laboratory experience you will soon encounter. You should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.


Review the Investigation procedures and watch the video above in preparation for the Lab.