Friday, May 22, 2015

Carbonate Connection Unit

published on: 2/13/2005

Contributing Teacher(s): Mark Mason

Subject Area: Science/Earth

Grade Range: Middle Grades (6-8)

Materials Needed:

  • Lab tables covered with a tough, disposable material such as poster board
  • safety goggles
  • materials to be tested (they must be labeled and in safe, easy to use containers)
  • a mild but not too weak solution (about .6 or .7 N) of Hydrochloric Acid (HCl) in plastic dropper vials
  • plastic lenses
  • paper towels
  • extra poster board pieces
  • pop-sickle sticks
  • red pens/pencils
  • handouts for the lessons and assignments

    Process Standards:

    • Goal 1.3 design and conduct field and laboratory investigations to study nature and society
    • Goal 1.6 discover and evaluate patterns and relationships in information, ideas and structures

    Content Standards:

    • Science 5. Processes (such as plate movement, water cycle, air flow) and interactions of earth’s biosphere, atmos...
    • Science 7. Processes of scientific inquiry (such as formulating and testing hypotheses)

      Time Allowance: About 7 class periods of 50 minutes

      Description: Use the Hydrochloric Acid test for Carbon Dioxide fizzing to determine if each of the 90 different materials are, or are not carbonates such as limestone.

      Classroom Component:

      Steps a teacher needs to implement this idea:

      A teacher will need to go to considerable efforts to gather the materials needed for the testing (your list of materials to test could be different from mine and still give a nice variety of materials to test). Students will benefit from some previous experience with the HCl test, possibly using a few obvious positive samples like limestone and calcite, a few obvious negative samples like granite and chert, and the difficult positive test like dolomite (fizzes only if you work up some powder). Of course, laboratory safety and cooperation are important in developing any type of laboratory lessons. Once the organization for the testing (grouping, procedures, etc.) is established plan on a full 50 minute class period for the students to do the predicting and the testing for each round. My suggestion is to follow each round of testing with a class period for discussion of the previous rounds results and to do the assignments.

      Accommodations for students with diverse learning needs:

      Students who have trouble focusing on the lab work should be grouped with partners who can help them to be successful. Otherwise, a less involved set of lessons with fewer tests or with teacher involved demonstrations may be needed.

      Carbonates and Scientific Methods



      Scientific Question: What materials release Carbon Dioxide gas when reacting with Hydrochloric Acid (HCl)?

      Background information: Carbonates are chemicals found in many types of minerals and rocks, the materials made from these rocks and minerals, and some substances that have undergone chemical reactions contain carbonates. All carbonates include a metal combined with a particle called a carbonate ion, this ion has the formula CO . The best known carbonates include calcium carbonate, magnesium carbonate, sodium carbonate, and sodium bicarbonate. Carbonates will release Carbon Dioxide gas when reacting with acids, causing a fizzing (bubbling) as the Carbon Dioxide is released into the air. To do the acid test always wear your safety glasses, carefully place a drop of HCl on the substance being tested, carefully observe for the fizzing effect indicating that this material contains Carbonates, materials tested that do not show the fizzing do not contain large amounts of carbonates. Carbonate rocks are generally limestones or dolomites, however, some sandstones, shales, and other rocks may also include enough carbonate to test positive with the acid. This project is going to 1st involve testing samples of minerals and rocks for carbonates, with the 2nd step to test materials used in building and construction for carbonates, with the 3rd round of testing being with household, medical, and miscellaneous materials.

      Hypothesis: The materials that I predict to contain carbonates are circled in red on the data sheet, those not marked are predicted not to contain carbonates.


      Carbonates Testing Round I
      Rocks and Minerals



      Circle or box in red, all substances you predict to be carbonates.

      Carefully test each substance with a drop of HCI (you must wear eye protection), fill in the chart.

      Material Name Carbonate
      Prediction Correct
      Iron Ore (local)    
      Cave Rock (local)    
      Sullivan sandstone (local)    
      Pseudo fossil (local)    
      Creek gravel (local)    
      Franklin Co. gravel (local)    
      Hwy 30 fossils (local)    
      Tiff (local)    
      Collection sandstone    
      Dover Cliffs    
      Badlands rock    
      Idaho lava    
      Volcanic landscaping rock    
      Elephant rocks    
      Utah Red rock    
      Springfield, MO gravel    
      Railroad bed gravel    
      Columbia, MO gravel    
      NE, MO gravel    
      Calcareous Tufa    
      Brown sandstone    
      Trap rock    
      TOTAL Yes =      No = Correct Predictions =

      Carbonates Testing Round I - Rocks and Minerals


      For additional information contact :
      Mark Mason
      Spring Bluff Elem.
      Spring Bluff R-XV
      (573) 457-8302

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      Material Name Carbonate
      Prediction Correct
      Iron Ore (local) No  
      >Cave Rock (local) Yes  
      Sullivan sandstone (local) No  
      Pseudo fossil (local) No  
      Creek gravel (local) No  
      Franklin Co. gravel (local) Yes  
      Hwy 30 fossils (local) Yes  
      Tiff (local) No  
      Collection sandstone Yes  
      Calcite Yes  
      Dover Cliffs Yes  
      Galena No  
      >Geodes No  
      Travertine Yes  
      Badlands rock Yes