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Determination of Ka of Weak Acids—Classic Lab Kit for AP® Chemistry

By: The Flinn Staff

Item #: AP6358 

Price: $36.05

In Stock [94 pcs available]. To view alternative items others have purchased, please see "Suggested Products" below.

The Determination of Ka of Weak Acids Classic Lab Kit for AP® Chemistry allows students to measure the Ka value for the ionization of two unknown acids. pH values are then measured and utilized, calculating the pKa value of each unknown.

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Classic AP Requirement #10—Determination of the Equilibrium Constant for a Chemical Reaction

Students measure the Ka value for the ionization of two unknown weak acids. pH values are measured and used to calculate the pKa value for each unknown weak acid. These values are used to determine the identity of each acid. This laboratory challenges the students’ understanding of the relationship among Ka, pH and H3O+ concentration while providing the recommended familiarity with the use of pH meters.

Complete for 24 students working in pairs.

Determination of Ka of Weak Acids Inquiry Guidance & AP® Chemistry Curriculum Alignment Transition Guide available! Follow the link in Resources to find this valuable publication that lets youadapt this classic AP Chemistry experiment for guided-inquiry and correlate with the AP Chemistry curriculum framework.


Materials Included in Kit: 
Acetylsalicylic acid, 4 g
Phenolphthalein solution, 0.5%, 30 mL
Potassium bisulfate, 4 g
Potassium bitartrate, 4 g
Potassium hydrogen phthalate, 4 g
Potassium phosphate, monobasic, 4 g
Sodium hydroxide solution, 0.1 M, 250 mL

Additional Materials Required (for each lab group): 0.01-g precision balances (3 to share), beaker, pH 4 and 7 buffer solutions, Erlenmeyer flask, graduated cylinder, pH Meter, Beral-type pipets, stirring rod, wash bottle with distilled or deionized water, weighing dishes.

Correlation to Next Generation Science Standards (NGSS)

Science & Engineering Practices

Analyzing and interpreting data
Planning and carrying out investigations
Using mathematics and computational thinking

Disciplinary Core Ideas

HS-PS1.B: Chemical Reactions

Crosscutting Concepts

Energy and matter
Scale, proportion, and quantity

Performance Expectations

HS-PS1-2: Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
HS-PS1-5: Apply scientific principles and evidence to provide an explanation about the effects of changing the temperature or concentration of the reacting particles on the rate at which a reaction occurs.