S

How Much Acid is in Fruit Juices and Soft

Drinks?Lab E

AP Chemistry Guided-Inquiry Experiments The College Board (2013). Investigation 4.

Lab Tasks

Design a plan for collecting data from an acid-base titration in order to answer your developed scientific question.

Select appropriate lab equipment, tools, and indicator to use in performing a titration.

Conduct and evaluate the results of an acid-base titration.

Represent what is occurring at the molecular level with visual diagrams.

Analyze data to identify patterns and relationships.

Make predictions and provide an explanation for a real-world application from the learning gleaned in this experiment.

Materials Available

Beakers of various sizes (100mL, 150mL, 250mL, and 400mL)

Buret (50mL)

Erlenmeyer flasks (125mL and 250mL)

Graduated cylinders ( 10mL, 25mL, and 100mL)

Volumetric Pipets (10mL, 25mL)

Droppers

Acid-Base Indicators

pH meter and paper

0.10M acetic acid

Sprite, Diet Sprite, Pineapple Juice (MUST BE LIGHT-COLORED!)

0.10M NaOH

0.25M NaOH

DI Water

Safety and Disposal

Goggles must be worn AT ALL TIMES!

NaOH is a skin irritant and can cause burns.

Was hands with soap and water after completing the lab.

After neutralization solutions may be washed down the drain with lots of water.

Lab “Warm-up”

Write a complete chemical equation for the reaction of a solution of sodium hydroxide (NaOH) with hydrochloric acid (HCl).

How many mL of 0.1M HCl are required to react completely with 5mL of 0.1 M NaOH?

If equal molar amounts of NaOH and HCl are mixed, when the reaction is complete what will be the chemical species in the resulting solution?

What will be the pH of the mixture in the above situation? Explain.

Write the complete chemical equation for the reaction of a 0.1M solution of acetic acid with a 0.1M solution of NaOH.

How many mL of 0.1 M NaOH solution will be required to react completely with 5mL of a 0.1M acetic acid solution? Explain.

How is it possible to determine when an acid-base reaction is complete when the concentration of one of the reactants is unknown?

Pre-Lab Assignment pg 41

1. Identify a research question pertaining to acid concentration in fruit juices and sodas. Propose a hypothesis that answers your question, and then outline a tentative procedure. Be sure to clearly identify which pieces of equipment you plan to use during your investigation.

2. Make a simple sketch showing how you plan to set up your equipment, labeling the following: analyte, titrant, buret, Erlenmeyer flask, volumetric pipette.

3.Be prepared to discuss with and finalize an investigation with your lab partner tomorrow! Your plan will then be proposed to Mrs. Bechtum.

4. Labs will be approved and conducted TOMORROW! Be prepared.

Safety and Disposal

Goggles must be worn AT ALL TIMES!

NaOH is a skin irritant and can cause burns.

Was hands with soap and water after completing the lab.

After neutralization solutions may be washed down the drain with lots of water.

Lab Day… and Beyond!

Consult with your partner to finalize a question and procedure. (10-15 minutes)

Approval from Mrs. Bechtum (5-10 minutes)

Data Collection (60 Minutes)

Lab Report Completed INDIVIDUALLY!

Lab Report Due Monday, September 8th!!

Complete Data Collection and Computation 1, 2, (Omit 3 & 4)

Complete Post-Lab Assessment 1, 2, 3, 4, and 7 (Omit 5

and 6)