Quest 6: pH

Q6P1: Acids and Bases are Everywhere!

Go to Google Classroom and open the assignment called "Q6P1: Acids and Based are Everywhere!" Read the text attached in the assignment carefully. Then, answer the questions on the worksheet also attached in the assignment. The questions go in order of the text. Please read the text! It is important that you understand what it is saying and that you don't just use the text to look up the answers. Please be very careful with the last 2 questions - read them carefully! That last question usually tricks students.

Do not turn this assignment in until you have checked in your work for the worksheet with Mrs. Roehm. Many students will need to make corrections to your answers - don't turn it in until Mrs. Roehm checks your answers!

Q6P2: Coloring the pH Scale

Grab a Household pHun page from the front table.

Color your Household pHun page to match the colors of this page (click the link). The colors must match! (You may need to blend colors)

Show Mrs. Roehm your colored Household pHun page.

Q6P3: Household pHun Lab

Complete the following Procedure:

1. Gather your materials. Each group should have a test tube rack with test tubes, a cup of cabbage juice and an eye dropper. This eye dropper can ONLY go in the cabbage juice! If a student places the cabbage juice eyedropper in any of the beakers at the lab stations, it will "contaminate" the entire solution. THIS EYEDROPPER MAY ONLY BE PLACED IN THE CABBAGE JUICE! During the lab, the eyedroppers at each station can only go in those beakers. Again, placing these eyedroppers in the cabbage juice or even in a different beaker will "contaminate" the entire sample.

2. You will test 12 of the substances set out at the lab station. (Your choice! You might not do all of the substances)

3. When you get to a station, you should:

Use the eyedropper to fill the test tube about 1/2 full of the household substance in the test tube. Use the eyedropper that is in the substance. NOT the red cabbage eye dropper.
Place one eyedropper full of the cabbage juice in the test tube. Use the right eye dropper!
Compare the color of the test tube to the cabbage juice scale on their lab sheet.
Write the name of the household substance next to he color that most closely matches the color of the test tube ON YOUR PAPER LAB DOCUMENT. By the end of the lab, it is important to know that you may not have one substance for every color. And, you may write more than one household substance at the same color.
When you are finished with their tests, you must organize your test tubes in order of pH to create your own pH scale.

BEFORE cleaning up, you must come to Mrs. Roehm and answer the questions listed below. This will be your assessment for this lab. EVERY member of the group will be asked to answer some of the questions and Mrs. Roehm will choose who answers which question. That means your group needs to prepare before coming to have Mrs. Roehm ask you the questions.

Show Mrs. Roehm your colored Household pHun page.

Chemistry Self Pacing Powerpoint 2025 (3).jpg

Q6P4: pHun With Citric Acid

Open up the pH Labs assignment in Google Classroom.

Complete the lab station pHun with Citric Acid. After you complete the lab, answer the questions. There are tips at the bottom of this post that will help you answer the questions. Don't forget to read these before answering the questions.

Procedure: pHun With Citric Acid

1. In a sandwich bag, place one scoop of citric acid into one corner of a sealable plastic bag.

2. Place one scoop of baking soda into the other corner of the bag.Seal the bag almost all of the way closed, leaving a small opening to pour in the cabbage juice.

3. Measure 20 mL of cabbage juice in a graduated cylinder.Pour the 20 ml of red cabbage juice into the corner of the bag that has the baking soda.

4. Seal the bag completely. But don't mix yet.

5. Hold the bag above a garbage can. Now, turn the bag so that the citric powder mixes into the baking soda mixture. Touch and feel!

5. Throw away the Ziploc bag.

Tips:

The reaction is much more dramatic if the students keep the powders in separate corners until the bag is sealed and they are ready to mix.
Have students hold the bag over a sink or garbage can. Sometimes the bag expands so much it pops!
Make sure the students touch the bag. It gets really cold!

Here is a quick video of students identifying evidence as they observe this reaction. Students get so excited during this station!

Answer the lab questions from the pH lab document in Google Classroom. The material property descriptions are linked in the pH Labs Assignment in Google Classroom.

1. For the question that asks, "Was this a chemical or physical reaction?", you must provide as much as possible! Your choices are color change, temperature change, pH change, gas production, and precipitate formation. So, if there is color change and gas production, you must include both. In addition, your evidence must include what you saw in the lab and what signs of a chemical change are from the text. Here is what I mean:

Not Acceptable: It was a chemical change because it changed colors.
Acceptable: It was a chemical change because it changed colors from red to black.

Not Acceptable: It was a chemical change because there was gas production.
Acceptable: It was a chemical change because there was gas production when bubbles were formed.

2. For the question that asks "What are some properties of the materials involved that changed?", you must provide 1 chemical property and 1 physical property. These MUST come from the materials descriptions linked in the assignment in Google Classroom. You must state the property that changed and the evidence from the text.

Not Acceptable: The color and reactivity changed.
Acceptable: The color of the reactant was white while the color of the product was colorless. The reactants were highly reactive with acids while the products were not reactive with acids.

Show Mrs. Roehm your answers before moving forward.

Q6P5: Rainbow of Bubbles and Magic Writing

Complete the Rainbow of Bubbles and Magic Writing lab stations from the pHantastic Chemical Reactions Lab in GC.

After you complete the lab, answer the questions. There are tips at the bottom of the previous that will help you answer the questions. Don't forget to read/remember these tips before answering the questions.

Procedure #1: Rainbow of Bubbles

1. Add 2 full eye droppers full of Universal Indictor to a test tube (It's the green liquid).

2. Add 1 eye dropper of ammonia to the Universal Indicator (It's the clear liquid). The liquid should be blue.

3. Drop ½ of an Alka-Seltzer tablet into the test tube.

Check out this video watching the reaction! It's so cool!

Magic Writing Set Up: MRS ROEHM MUST SHOW YOU HOW TO DO THIS!!!!!!!!!!

Procedure: Magic Writing

1. ASK MRS ROEHM HOW TO DO THIS.

2. Dip a Q-tip into the phenolphthalein. (Phenolphthalein is a base indicator. It turns pink in the presence of a base.) Use the wet swab to write a message on a white sheet of paper

3. Spray the message using the bottle labeled "Ammonia".

4. Spray the message using the bottle labeled "Vinegar".

Tips:

It is crucial that there is a garbage can and paper towels at this station. IMMEDIATELY after each group/student finishes spraying the liquids, throw away the paper and wipe down the counter. Without this step, the odor in the room becomes very strong.
As mentioned earlier, it is important to wear goggles when spraying acids and bases.
If you have spent time with red cabbage juice as an indicator, students get the misconception that pink means "acid". Take the time to explain that phenolphthalein turns pink in the presence of a base. Students have the tendency to say that the message appears because "ammonia is an acid" when ammonia is really a base due to the fact that they do not realize that different pH indicators turn different colors than red cabbage juice.
If students are having a hard time determining whether vinegar and ammonia are acids or bases, I have them refer to their Household pHun! Lab document completed in a lesson previous to this.

Answer the lab questions for these stations in the pHantastic Chemical Reactions lab in GC. The material property descriptions are linked in the document.

Show Mrs. Roehm your answers before moving on to the next station.

Q6P6: Aunt Acid... Way off base, or the Neutralizer?

Complete the Aunt Acid Lab. After you complete the lab, answer the questions on the lab document in GC.

Procedure: Aunt Acid...Way off base, or the Neutralizer?

1. Add an eyedropper of vinegar (the beaker with the tin foil on top of it) to a test tube. (This represents stomach acid)Add red cabbage juice to determine the pH level.

2. Add an eyedropper of of the "antacid juice" (the other beaker with the powder at the bottom of the beaker) to a different test tube.

IMPORTANT: Antacids are medicine that helps an upset stomach. Often times, when you have a stomach ache it's because you have too many acids in your stomach.)

3. Add drops of red cabbage juice to determine the new pH level.

4. Add enough drops that you can clearly see what color it has turned.

5. Now, combine the two test tubes together.

Tips:

Remember that red cabbage juice as a pH indicator. Pink represents an acid, purple/blu indicates a neutral substance, and green shows a base.

6. Answer the lab questions on the lab document.

Show Mrs. Roehm your answers for a signature.

Q6P7: Reassess

Look at your CH.6 Skill on your learning target page. I have linked it here, but you should reassess on the physical paper copy you have in your folder/binder.

Reassess. Go tell Mrs. Roehm your strength and what you are still working on.