Acid Test

Your goal is to identify samples according to their reactivity with acid. Minerals that react are called chemical rocks, and minerals that don’t are called clastic rocks. Some chemical rocks contain carbonate minerals, like limestone, dolomite, and marble which react with the acid.
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8 Responses to “Acid Test”
  1. Aurora says:

    Sometimes vinegar isn’t strong enough (I have found out that it can vary between 2.5-4.5 pH), which is why we use the diluted HCl, but this isn’t something we want you to work with. There are other ways of testing the rocks. Is it just the limestone that you are trying to find? If so, you can leave it overnight in a cup of vinegar and compare with in the morning to see if there are any bubbles on the surface. Tkae a photo just after you drop it in, and then again in the morning to compare.

  2. jennifer_rice says:

    I have the Washington Student rocks and minerals bag but I am having trouble identifying the minerals in the bag. I have used the field guide but still don’t feel confident that I am using the correct minerals. My rocks didn’t react at all when I applied the vinegar. Do you have any suggestions on how I can accurately identify the minerals?

    Thank you!
    Abigail

  3. Aurora says:

    Sure! The link to our worksheet is just below the video. You can access it here as well (it’s on the second page of the PDF):

    https://www.sciencelearningspace.com/standardcontent/docs/Unit20-acid-test.pdf

  4. Gina Gazelka says:

    Can you tell me where to find the Mineral Test Data Table that you show in the video. I would like to download and print it for our use. Thanks!

  5. Aurora says:

    Your rocks may have only a small amount of the carbonate, so you may only get a small reaction. You can try a stronger acid, but white vinegar is still pretty strong as far as being able to get a reaction. (If you want a reaction just for the fun of it, dunk the rock in baking soda and then add the vinegar.)

  6. Leah Thompson says:

    I only got a small reaction from my rocks how do I get a bigger reaction.

  7. Aurora says:

    Thanks – we’ll get those fixed right away!

  8. Terri Cleary says:

    I’ve noticed that you are re-doing a number of topics. Here are a few typos I found for this section:
    Paragraph 3 after the video
    A lot of rocks contain small amounts of calcite or other carbonate minerals, so all of these make a ?fizz?

    Paragraph 4 after the video
    releasing carbon dioxide gas into the ?air?

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