Lesson 2 Acid/Base Titraton Experiment
Part of Curriculum Unit:Point of inflection of a logistic curve
Abstract help
Students are going to conduct a acid/base titration experiment to gather data. This activity has a cross-curricular connection with chemistry. The purpose is to determine the unknown concentration of an acid solution by titrating with a strong base of known concentration.
On the previous day students entered data from the contagious disease experiment which they use to find the logistic curve, derivatives and point of infection using the TI-83 calculator. This had a cross-curricular connection with biology.
On the day following this lesson, students will enter this data into the TI-83 and study the point of inflection first by using the CMBDERIV program on the TI-83 and then by the best-fit curve as in lesson one.
On the previous day students entered data from the contagious disease experiment which they use to find the logistic curve, derivatives and point of infection using the TI-83 calculator. This had a cross-curricular connection with biology.
On the day following this lesson, students will enter this data into the TI-83 and study the point of inflection first by using the CMBDERIV program on the TI-83 and then by the best-fit curve as in lesson one.
National Standards help
Mathematics instructional programs should include attention to data analysis, statistics, and probability so that all students
Pose questions and collect, organize, and represent data to answer those questions
Mathematics instructional programs should emphasize connections to foster understanding of mathematics so that all students
Recognize and use connections among different mathematical ideas
Recognize, use and learn about mathematics in contests outside of mathematics.
Representation
Mathematics instructional programs should emphasize mathematical representations to foster understanding of mathematics so that all students
Create and use representations to organize, record, and communicate mathematical ideas
Develop a repertoire of mathematical representations that can be used purposefully, flexibly, and appropriately
Use representations to model and interpret physical, social, and mathematical phenomena.
Pose questions and collect, organize, and represent data to answer those questions
Mathematics instructional programs should emphasize connections to foster understanding of mathematics so that all students
Recognize and use connections among different mathematical ideas
Recognize, use and learn about mathematics in contests outside of mathematics.
Representation
Mathematics instructional programs should emphasize mathematical representations to foster understanding of mathematics so that all students
Create and use representations to organize, record, and communicate mathematical ideas
Develop a repertoire of mathematical representations that can be used purposefully, flexibly, and appropriately
Use representations to model and interpret physical, social, and mathematical phenomena.
Pre-requisite Skills help
use of the TI-83
use of the CBL
use of the CBL
Teacher Information help
Students probably could conduct this experiment with no prior use of a CBL with a little instruction as the CBL will give directions.
Since this is in a math class, I may have four or five chemistry students present this experiment to the class and link the data to the rest of the class.
The CHEMBIO application must be loaded in the calculator and the experiment in its entirety can be found in the TI CHEMBIO packet.
Materials:
TI-83 with link cable
CSBL
pH probe and amplifier
.10-.25 M HC2H3O2
.10 M NaOH
Phenolphthalein indicator
Buret
Ring stand with buret clamp
250-mL beaker
Teacher should conduct experiment first before doing this lesson.
Since this is in a math class, I may have four or five chemistry students present this experiment to the class and link the data to the rest of the class.
The CHEMBIO application must be loaded in the calculator and the experiment in its entirety can be found in the TI CHEMBIO packet.
Materials:
TI-83 with link cable
CSBL
pH probe and amplifier
.10-.25 M HC2H3O2
.10 M NaOH
Phenolphthalein indicator
Buret
Ring stand with buret clamp
250-mL beaker
Teacher should conduct experiment first before doing this lesson.
Student Activity help
Students will conduct the acid/base titration experiment from the TI 1999 CHEM/BIO participant packet.
Procedure:
Link calculator to CBL and connect pH probe and amplifier to Channel 1 using gray DIN adapter.
Set up equipment as shown in the participant packet.
Conduct experiment as described in the packet.
Below is a summary of that experiment.
Place 50 mL of distilled water into a 250 mL beaker and add 10 mL of acid solution to the beaker along with 3 drops of phenolphthalein indicator.
Run the Chembio program and make the following selections:
Set up Probes
1 probe
pH probe in Channel 1
use stored calibration
collect data
trigger prompt
Stir beaker with probe, press trigger when CBL screen stablizies, and enter 0 to indicate no base haws been added. Press 1 to collect more data.
Enter small amount of base (5 mL) and repeat the procedure and answer the screen prompt. Collect data until the pH values level off. (somewhere around 12) Record the volume of base added when the indicator changes color to light pink.
When the titration is complete select Stop and Graph.
Press enter and select no and quit.
Turn on STAT Plot 1 for L1 and L2. Press zoom 9.
Trace to find the volume that corresponds to the point with the greatest change in pH.
Students will discuss how this equivalence point compares to the indicator's change of color.
Procedure:
Link calculator to CBL and connect pH probe and amplifier to Channel 1 using gray DIN adapter.
Set up equipment as shown in the participant packet.
Conduct experiment as described in the packet.
Below is a summary of that experiment.
Place 50 mL of distilled water into a 250 mL beaker and add 10 mL of acid solution to the beaker along with 3 drops of phenolphthalein indicator.
Run the Chembio program and make the following selections:
Set up Probes
1 probe
pH probe in Channel 1
use stored calibration
collect data
trigger prompt
Stir beaker with probe, press trigger when CBL screen stablizies, and enter 0 to indicate no base haws been added. Press 1 to collect more data.
Enter small amount of base (5 mL) and repeat the procedure and answer the screen prompt. Collect data until the pH values level off. (somewhere around 12) Record the volume of base added when the indicator changes color to light pink.
When the titration is complete select Stop and Graph.
Press enter and select no and quit.
Turn on STAT Plot 1 for L1 and L2. Press zoom 9.
Trace to find the volume that corresponds to the point with the greatest change in pH.
Students will discuss how this equivalence point compares to the indicator's change of color.
Assessment help
All students will participate in an experiment. They will be accessed on their participation and ability to collect the needed data by use of technology and link the data to those observing.
Enrichment / Alternative Activity help
students will use data gathered to find tangents along the curve using the slope formula to explore the change per delta x and estimate a point of inflection.
Technology Requirements/Integration help
Use of TI-83 calculator
Use of CBL and probes
Use of CBL and probes