RED CABBAGE INDICATOR

LAB: RED CABBAGE INDICATOR

This unit has introduced you to some of the general properties of acids and bases. You’ve learned about the pH scale that helps tell you about the relative strength of acids (pH lower than 7) and bases (pH higher than 7). You’ve also learned about a few different compounds, called indicators, that can help you visually determine the pH of a liquid. Today, we will be making and using our own indicator to help us determine the pH of some common household liquids.

Don't use plagiarized sources. Get Your Custom Essay on
RED CABBAGE INDICATOR
Get a plagiarism free paper Just from $13/Page
Order Essay

 

 

 

Learning Goals:

Students will follow a procedure to make their own indicator solution
Students will use their indicator to make observations of different household objects
Students will make predictions about the properties of the observed liquids
Students will explain the chemistry of a neutralization reaction

 

 

Vocabulary:

Acid: A substance that generally increases the concentration of H+ (H3O+) ions in a solution
Base: A substance that generally decreases the concentration of H+ (H3O+) ions, or increased the concentration of OH- ions in a solution
pH Scale: The scale used to quantify the strength of an acid or base relative to pure water (with a pH of 7)
Indicator: A compound used to visually determine the relative pH of a solution
Hydronium Ion: H3O+. Often created when an acid donates an H+ ion to a solution.
Hydroxide Ion: OH-. Often created when a base donates an OH- ion to a solution, or when a base removes an H+ ion from a solution.
Neutralization: A reaction involving an acid and a base where H+ ions combine with OH- ions to create neutral water (H2O)

Part 1: Making the indicator

 

 

Material Needed:

One head of red cabbage (green cabbage will NOT work)
Large kitchen knife and cutting board
Large stock pot
Water
Stove or other controlled heating surface
A pitcher or large bowl
A strainer or colander

 

 

Procedure:

Using the cutting board and kitchen knife, cut up your head of red cabbage into small pieces.
Place a few cups of your cut-up cabbage (2-4 cups will be enough) into your large stockpot
Pour water into your stock pot until the water level just covers the cabbage.
Turn the stove on to high heat and bring the water to a boil
Once the water starts boiling, turn of the stove and allow the water to cool (20-30 minutes)
Set out your storage container for your cabbage indicator solution, either a pitcher or a large cup or bowl.
Strain the cabbage mixture into your storage container, making sure to catch any large chunks of cabbage. Set aside your cabbage indicator solution for use later. You should have a few cups worth of indicator

Your cabbage indicator should have a deep purple color. Red cabbage contains the pigment anthocyanin that changes color when it is mixed with an acid or base. The pigment turns red when mixed with acids and turns blue or bluish-green when mixed with basic solutions. The amount of color change is related to the strength of the acid or base. A deeper red color would indicate a stronger acid than a light red or red-purple color.

 

 

 

Part 2:

 

Now we will find a few common edible acids and bases from your kitchen. Try to find any of the following. Aim for at least 4 or 5 liquids, but more is better. One of your liquids should be water.

Water
Lemon juice
Milk
Baking soda (dissolved in water)
Vinegar
Antacid (either dissolve an alka-seltzer tablet in water, or grind up a “Tums” tablet and dissolve in water)
Green tea
Coffee or black Tea
Simple syrup (table sugar dissolved in water)

 

 

Pour out a small amount of your chosen liquids and let them come to room temperature. Now it’s time to apply what you’ve been learning from your lessons. Recall that acidic substances often taste “tart” or “sharp” and that bases often taste bitter and might have a slippery feel on your skin. Try tasting and feeling each liquid that you found in your kitchen. Keep track of your observations in the table below (no need to write full sentences, but try to use a few words for each observation). Keep a small portion of each liquid for use in part 3 of the project.

 

 

 

NOTE: The liquids used in this project are common food items and only weak acids acids or bases. You should obviously never taste or feel unknown liquids, especially those that are classified as strong acids or bases.

 

 

 

Part 3: Conducting the experiment

 

Hypothesis:

 

Use your background knowledge to make an informed prediction about the results of your experiment. Think about the different variables in the experiment and how they might affect each other. What variable are you changing yourself (independent variable). What variable are you measuring (dependent variable)? What things are you keeping the same throughout the experiment? Hypotheses are best in an “If/then format” that make a prediction between the variables in your experiment. For example: If I change [my independent variable], then I will see [these changes] in my [dependent variable]. For this experiment, you should try to predict which liquids will be an acid, base, or neutral.

 

 

 

Materials:

Prepared cabbage indicator from part 1 (room temperature)
Small amounts of your acquired liquids from part 2, labeled (room temperature).
Enough clear cups or glasses for each of your liquids from part 2
A tablespoon
A ½ or ¼ teaspoon
Tape and marker

 

 

Instructions:

Pour 1 cup of your cabbage indicator into a clear glass for each liquid you plan to test (if you don’t have enough cabbage indicator for each glass, you can use a smaller amount of indicator – just use the same volume for each)
Take 1 tablespoon of one of your liquids from part 2 and pour it into one of the glasses containing the cabbage indicator. Stir the mixture. Use the tape and marker to label the glass with the type of liquid you added.
Repeat step 2 with the rest of your liquids
Make observations about the color change in each glass. Try to be as specific as possible because some colors might be very similar. You are free to take pictures or use colored pencils to record your observations. You might want to create your own table to help organize your observations and make them easier to compare.
Once every mixture has had a chance to react and change color (no more than 5 minutes), identify a weak base from among your liquids (slight blue color) and your strongest acid (red color with very little purple left).
Take a very small amount of the original acidic liquid (¼ or ½ of a teaspoon) and add it to the weak base and cabbage indicator solution. Stir to mix the liquids
Make observations about any color changes that might have occured. If you didn’t notice any color changes, keep adding the acidic liquid in small amounts until the liquid returns to the neutral purple color of cabbage indicator mixed with water. Keep track of how much liquid you added until the solution turns purple
After gathering all of your data and observations, you can dispose of all your liquids and begin compiling your lab report

 

 

Questions:

Which liquids did you identify as acids? Why?
Which liquids did you identify as bases? Why?
Which liquids did you identify as neutral? Why?
Could you tell the relative strengths of acids and bases in your experiment? How?
How much volume of acid did it take to neutralize the basic solution? If you added different volumes of the acid and the base to get a neutral color for the indicator, why did it take more amounts of one type of liquid to reach neutralization?
What do you think was happening to the ions during the neutralization reaction?

 

 

Conclusion:

 

Write your conclusion. Don’t forget to discuss your hypothesis and use your data to support your conclusion. Talk about the concepts you learned and how they connect to the previous lessons and to real life. Evaluate the experiment itself and think about how it might be improved or expanded upon. Your conclusion should be 5 or more sentences in length. Look through the sample Lab Report Format for more guidance.

 

Summary of Submission Requirements:

Heading and unique title
Pre-lab, hypothesis, procedure, data, analysis, and conclusion section headings
Each section is complete and thorough
Completed lab report submitted through TurnItIn
Ignitia assignment submitted with TurnItIn Submission ID

Steps of Project Overview:

Project Overview

Additional Resources:

Downloadable copy of assignment
LiveBinder

Lab Report Rubric:

 

 

 

 

Lab Report Format

 

Last Name Page #

 

Student Name

 

Teacher Name

 

Course Name

 

Due Date

 

Title

 

 

Hypothesis

A prediction of what you think the result of the project will be. Write your hypothesis before you begin the experiment. A common sentence form for a hypothesis is to use an “if…then…” statement.

 

Materials

List the materials that you used to complete the experiment.

 

 

Procedure

Summarize the steps that you took to complete this experiment; the procedure should be written in 3rd person present tense, and it should give enough information for someone to repeat the experiment using only your procedure. Make sure to include any modifications you make.

 

 

Data

Write a detailed description of your observations, results, and any measurements. Do not interpret or try to explain your data; that discussion belongs in your conclusion. Try to use a table to organize your data if you can.

 

 

Calculations/Questions

Perform any calculations using your data and present the results here. Answer any questions from the prompt. Number your responses so that they correspond with the given questions. Do not type the questions themselves into this section; instead, restate the question within your response.

 

Conclusions

Begin by stating whether your hypothesis was true or false, and use specific data/observations/results to support your answer. Discuss how this experiment connects to some of the concepts you’ve been learning in this unit. How might these concepts apply to other areas of science or to your everyday life? Finally, discuss how the experiment went. Do you trust your results? What possible sources of errors or uncertainty were there? How might you improve the procedure to make the experiment better in the future (there is always something that can improve your data). What new questions do you have and how might you investigate them in the future (a general comment or two is fine)? A conclusion should be 5 or more sentences in length.

Master Homework
Order Now And Get A 20% Discount!
Pages (550 words)
Approximate price: -

Advantages of using our writing services

Custom Writing From Scratch

All our custom papers are written by qualified writers according to your instructions, thus evading any case of plagiarism. Our team consists of native writers from the USA, Canada, and the Uk, making it convenient for us to find the best to handle your order.

Unlimited Free Revisions

If you feel your paper didn't meet all your requirements, we won't stop till it's perfect. You're entitled to request a free revision within 7 days after we submit your paper.

Quality Writing In Any Format

If you have issues with citing sources and referencing, you need not worry. Our writers are highly knowledgeable in referencing, including APA/MLA/Havard/Chicago/Turabian and all other formatting styles.

Fast Delivery And Adherence To The Deadline

All our custom papers are delivered on time, even the most urgent. If we need more time to perfect your paper, we may contact you via email or phone regarding the deadline extension.

Originality & Security

At Master Homework, your security and privacy is our greatest concern. For this reason, we never share your personal information with third parties. We use several writing tools to ensure your paper is original and free from plagiarism.

24/7 Customer Support

Our agents are online 24 hours a day, 7 days a week, and are always ready to serve you. Feel free to contact us through email or talk to our live agents whenever you need assistance with your order.

Try it now!

Calculate the price of your order

We'll send you the first draft for approval by at
Total price:
$0.00

How it works?

Follow these simple steps to get your paper done

Place your order

Fill in the order form and provide all details of your assignment.

Proceed with the payment

Choose the payment system that suits you most.

Receive the final file

Once your paper is ready, we will email it to you.

Our Services

We work nonstop to see the best client experience.

Pricing

Flexible Pricing

We offer pocket-friendly prices that coincide with the preferred client's deadline.

Communication

Admission help & Client-Writer Contact

Our support team is always ready to ensure vital interaction between you and the writer whenever you need to elaborate on something.

Deadlines

Paper Submission

We deliver our papers early within the stipulated deadlines. We are glad to help you if there should be an occurrence of any alterations required.

Reviews

Customer Feedback

Your review, positive or negative, is of great concern to us and we take it very seriously. We are, consequently adjusting our policies to ensure the best customer/writer experience.