July/August 2017 – Vol. 29 No. 8

Acids and Bases Lab

Posted: Tuesday, February 1st, 2011

by Jeff Bradbury and Patricia Buchanan

Name ____________________

Date _____________________

Partners’ Name ____________

Question: When using materials to clean our house, are the products used usually acidic or basic, Why do you think so?

Purpose: To determine the importance of acids and bases while measuring the pH of different substances.

Part 1 Introduction:

In this lab you will be working in groups of two.

Acids were first recognized as substances that taste sour (The sour taste of lemons and limes is due to citric acid), will dissolve certain metals, and will dissolve some types of rocks.

Bases were characterized by their bitter taste and slippery feel (Hand soaps and toothpastes, for example).

A neutral solution is neither basic nor acidic.  Acids and bases will react together to form neutral solutions.  One can say that an acid will neutralize a base and vice-versa.

Indicators are substances that change color depending on whether they are in an acidic or basic solution.

In today’s lab you will observe some characteristic chemical and physical properties of acids and bases.

SAFETY

Safety goggles must be worn at all times. Hydrochloric acid, HCl, and acetic acid, HC2H3O2 can harm eyes, skin, and clothing.  Handle with care.  Any acid spilled on the skin or splashed into your eye should be rinsed with a large volume of water. NaOH and NH3(aq) solutions are corrosive to the skin and can harm your eyes.  Any base spilled on the skin or splashed into your eyes should be rinsed with a large volume of water.

Measuring pH with pH (Universal indicator) paper:

In your spot plate, obtain a sample (half-fill the wells) of each of the solutions shown in the table below.  Dip a small (1cm) piece of Universal Indicator paper into each well.  Record the color of the paper and match the color to the pH scale on the tube of paper.

Measuring pH with cabbage juice:

Make sure there is no Universal Indicator paper in the solution wells.  Obtain a piece of purple cabbage (one leaf) from the reagent bench.  Break it up into small pieces and boil it in about 150 ml of de-ionized water in a 250 ml beaker.  Add 15 drops of the cabbage juice extract to each of the wells of your spot plate.  Make sure you add the same amount of extract to each well.  Record the color of each solution.

Complete the table that compares the colors of each pH indicator at each pH

Table 1: Chemicals and their pH

Solution Color of cabbage juice Color of pH paper pH
.1 M HCL
.01 M HCl
.001 M HCl
.1 M NaOH
.01 M NaOH
.001 M NaOH
Windex
Milk
Orange Juice
Distilled water
Honey
Vinegar
NaCl
Tap water
Lemon juice

Compare your results with others in your group. Re-test those that are different.

Dispose of all solutions into the sink.

Complete the table showing the color of cabbage juice at each pH. 1-14.

Cabbage juice color pH
1
2
3
4
5
6
7
8
9
10
11
12
13
14

Acid Base Notes

Properties of Acids and Bases
Chemistry of Acids and Bases

Questions and Answers:

1.       Which substances had different pH’s than you expected?

2.       Why are acids and bases important?

3.       Were the household cleaners basic or acidic or both?

4.       What does pH mean to you now?

Jeff Bradbury is a professor of chemistry at Cerritos College in Norwalk and is community college director for CSTA; Patricia Buchanan is the Cal Grip Grant Project Assistant at Cerritos College. The original idea for this activity came from the Los Angeles County Office of Education 15 years ago, which the authors modified.

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

Leave a Reply

LATEST POST

CTC Seeking Educators for Science Standard Setting Conference

Posted: Wednesday, August 16th, 2017

The Commission on Teacher Credentialing (CTC) and Evaluation Systems group of Pearson are currently seeking California science educators to participate in a Science Standard Setting Conference for the California Subject Examinations for Teachers (CSET) program. Each standard setting panel is scheduled to meet for one-day, in Sacramento, California. The fields and dates are listed below:

Multiple Subjects Subtest II (Science), Monday, October 2, 2017
Science Subtest II: Physics, Monday, October 2, 2017
Science Subtest II: Chemistry, Tuesday, October 3, 2017
Science Subtest II: Life Sciences, Wednesday, October 4, 2017
Science Subtest II: Earth and Space Sciences, Thursday, October 5, 2017
Science Subtest I: General Science, Friday, October 6, 2017

The purpose of the conference is for panel members to make recommendations that will be used, in part, by the Commission on Teacher Credentialing (CTC) in setting the passing standard, for each field, in support of the updated California Subject Examinations for Teachers (CSET).

Click here to nominate educators. If you are interested in participating yourself, complete an application here for consideration.

Eligibility:

Public school educators who are:

• Certified in California
• Currently practicing (or have practiced within the last school year) in one or more of the fields listed above. 

College faculty who are:

• Teacher preparation personnel (including education faculty and arts and sciences faculty)
• Practicing (or have practiced within the last school year) in one or more of the fields listed above, and
• Preparing teacher candidates in an approved California teacher preparation program.

 Benefits of Participation Include:
• Receive substitute reimbursement for their school (public school educators only),
• Have the opportunity to make a difference in California teacher development and performance,
• Have the opportunity for professional growth and collaboration with educators in their field,
• Be reimbursed for their travel and meal expenses, and
• Be provided with hotel accommodations, if necessary.

For more information, visit their website at www.carecruit.nesinc.com/cset/index.asp

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

CSTA Annual Conference Early Bird Rates End July 14

Posted: Wednesday, July 12th, 2017

by Jessica Sawko

Teachers engaged in workshop activity

Teachers engaging in hands-on learning during a workshop at the 2016 CSTA conference.

Don’t miss your chance to register at the early bird rate for the 2017 CSTA Conference – the early-bird rate closes July 14. Need ideas on how to secure funding for your participation? Visit our website for suggestions, a budget planning tool, and downloadable justification letter to share with your admin. Want to take advantage of the early rate – but know your district will pay eventually? Register online today and CSTA will reimburse you when we receive payment from your district/employer. (For more information on how that works contact Zi Stair in the office for details – 916-979-7004 or zi@cascience.org.)

New Information Now Available On-line:

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

Goodbye Outgoing and Welcome Incoming CSTA Board Members

Posted: Wednesday, July 12th, 2017

Jill Grace

Jill Grace, CSTA President, 2017-2019

On July 1, 2017 five CSTA members concluded their service and four new board members joined the ranks of the CSTA Board of Directors. CSTA is so grateful for all the volunteer board of directors who contribute hours upon hours of time and energy to advance the work of the association. At the June 3 board meeting, CSTA was able to say goodbye to the outgoing board members and welcome the incoming members.

This new year also brings with it a new president for CSTA. As of July 1, 2017 Jill Grace is the president of the California Science Teachers Association. Jill is a graduate of California State University, Long Beach, a former middle school science teacher, and is currently a Regional Director with the K-12 Alliance @ WestEd where she works with California NGSS K-8 Early Implementation Initiative districts and charter networks in the San Diego area.

Outgoing Board Members

  • Laura Henriques (President-Elect: 2011 – 2013, President: 2013 – 2015, Past President: 2015 – 2017)
  • Valerie Joyner (Region 1 Director: 2009 – 2013, Primary Director: 2013 – 2017)
  • Mary Whaley (Informal Science Education Director: 2013 – 2017)
  • Sue Campbell (Middle School/Jr. High Director: 2015 – 2017)
  • Marcus Tessier (2-Year College Director: 2015 – 2017)

Learn More…

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

Finding My Student’s Motivation of Learning Through Engineering Tasks

Posted: Wednesday, July 12th, 2017

by Huda Ali Gubary and Susheela Nath

It’s 8:02 and the bell rings. My students’ walk in and pick up an entry ticket based on yesterday’s lesson and homework. My countdown starts for students to begin…3, 2, 1. Ten students are on task and diligently completing the work, twenty are off task with behaviors ranging from talking up a storm with their neighbors to silently staring off into space. This was the start of my classes, more often than not. My students rarely showed the enthusiasm for a class that I had eagerly prepared for. I spent so much time searching for ways to get my students excited about the concepts they were learning. I wanted them to feel a connection to the lessons and come into my class motivated about what they were going to learn next. I would ask myself how I could make my class memorable where the kids were in the driver’s seat of learning. Incorporating engineering made this possible. Learn More…

Powered By DT Author Box

Written by NGSS Early Implementer

NGSS Early Implementer

In 2015 CSTA began to publish a series of articles written by teachers participating in the California NGSS k-8 Early Implementation Initiative. This article was written by an educator(s) participating in the initiative. CSTA thanks them for their contributions and for sharing their experience with the science teaching community.

State Schools Chief Tom Torlakson Unveils Updated Recommended Literature List

Posted: Wednesday, July 12th, 2017

SACRAMENTO—State Superintendent of Public Instruction Tom Torlakson unveiled an addition of 285 award-winning titles to the Recommended Literature: Prekindergarten Through Grade Twelve list.

“The books our students read help broaden their perspectives, enhance their knowledge, and fire their imaginations,” Torlakson said. “The addition of these award-winning titles represents the state’s continued commitment to the interests and engagement of California’s young readers.”

The Recommended Literature: Prekindergarten Through Grade Twelve list is a collection of more than 8,000 titles of recommended reading for children and adolescents. Reflecting contemporary and classic titles, including California authors, this online list provides an exciting range of literature that students should be reading at school and for pleasure. Works include fiction, nonfiction, poetry, and drama to provide for a variety of tastes, interests, and abilities. Learn More…

Written by Guest Contributor

From time to time CSTA receives contributions from guest contributors. The opinions and views expressed by these contributors are not necessarily those of CSTA. By publishing these articles CSTA does not make any endorsements or statements of support of the author or their contribution, either explicit or implicit. All links to outside sources are subject to CSTA’s Disclaimer Policy: http://www.classroomscience.org/disclaimer.