Khan Academy
Khan Academy: Relationship Between Ka and Kb
Learn about the relationship between Ka of a weak acid and Kb for its conjugate base. Practice equations for converting between Ka and Kb, and converting between pKa and pKb.
Study Languages
Study Spanish: Subjunctive: Regular Stem Changing
Comprehensive lesson on how to conjugate verbs in the present subjunctive. Regular and stem-changing verbs are presented in this explanation. A quiz at the end of the lesson tests the student's mastery of verb conjugations in the present...
Study Languages
Study Spanish: Subjunctive: Spelling Changes
Fantastic explanation of spelling changes in the Spanish language and their effect upon conjugations in the present subjunctive. Verb infinitives that end in -car, -gar, and -zar are among those that are considered. A quiz at the end of...
Study Languages
Study Spanish: Subjunctive: Irregular Verbs
Great explanation of how to conjugate the six irregular verbs in the present subjunctive: dar, estar, haber, ir, saber, and ser. A quiz at the end of the lesson tests the student's mastery of irregular conjugations in the present...
Paul Dawkins
Paul's Online Notes: Complex Numbers Primer
This tutorial reviews complex numbers, notation associated with complex numbers, and the basic operations involving complex numbers. Topics examined are conjugates and moduli, polar form, exponential form, arithmetic of complex numbers,...
Oswego City School District
Regents Exam Prep Center: Multiply and Divide Complex Numbers
This tutorial shows students how to multiply and divide complex numbers and includes the topic of conjugates. Includes link to a graphing calculator tutorial.
Colby College
Spanish Language & Culture: Past Subjunctive Forms
Completion of these twenty-five clauses provide extensive practice of the past subjunctive tense. Verb infinitives are provided that need to be conjugated in the imperfect subjunctive according to the subject that proceeds it. Answers...
University of Texas at Austin
Ut Austin: Introduction to French Verbs
Excellent overview of French verbs! Defines a verb, introduces the concepts of infinitives, conjugations (with sample), common auxiliaries and modals, transitive vs. intransitive and the formation of present and past participles - all in...
Colby College
Spanish Language & Culture: El Preterito Formas (Part 3)
These Colby College exercises provide a very extensive review of irregular verbs, stem-changers, and spelling changes in the preterite tense. Change present tense conjugations to preterite tense. Answers may be checked and corrected.
Other
English Spanish Link: Creative
This site offers newspapers and magazines from various Spanish countries along with a tool bar that includes a spell checker, verb conjugator, Spanish and English dictionary, Spanish verbs and much more. Available in Spanish and English.
Chemistry Collective
Chem Collective: Designing a Buffer Solution With a Specific P H
Create a buffer solution at a specific pH using a weak acid and its conjugate base.
Lawrence Berkeley National Laboratory
Berkeley Lab: Charge, Parity, and Time Reversal (Cpt) Symmetry
A simple explanation of the development of three principles of symmetry: parity, time reversal invariance, and charge conjugation.
College Claparede (Switzerland)
Edu.ge.ch: English Exercises: Irregular Verbs 1
This 30-question quiz asks students to select the missing verb from the conjugation; for example, bite-bit-select bitten from the drop down menu. Java is required.
Language Guide
Language Guide: Future and Conditional
Learn the formation of the future and conditional tenses for both regular and irregular verbs. Three sets of links to practice verb conjugations are under each model.
English Zone
English zone.com: Confusing Verbs Lay / Lie 1
Ten practice sentences that ask students to fill in the blank with the correct conjugation of the verb "lay" and "lie."
English Zone
English zone.com: Be Verb Practice #1
Eight sentences with blanks where the "be" verb should be. Students practice conjugating the verb correctly while completing each sentence.
Languages Online
Languages Online: Si Clauses + Conditional Tense
This exercise-practice the teaches students how to write imperfect subjunctive and the conditional tense used in Spanish "if-would" clauses. Fill in the blank with the conditional or past subjunctive form of the verb. Answers may be...
Chemistry Collective
Chem Collective: Unknown Weak Acid Problem
Perform an experiment to determine the pKa and concentration of an unknown acid.
Chemistry Collective
Chem Collective: Unknown Weak Acid Problem Bonus
Perform an experiment to determine the concentrations of a mixture of two acids.
Chemistry Collective
Chem Collective: Unknown Base Problem
Perform an experiment to determine the pKa and concentration of an unknown weak base.
Chemistry Collective
Chem Collective: Determining the P Ka and Concentration Ratio
Use the virtual lab to determine the pKa of a protein then create a buffer solution with a specific concentration ratio of the protein in its protonated/ unprotonated form.
Chemistry Collective
Chem Collective: Unknown Acid and Base Problem
In this exercise, students graph the titration curve of an unknown acid and base to determine their pKa's and concentrations.
Chemistry Collective
Chem Collective: Dna Dye Binding: Equilibrium and Buffer Solutions
Students examine equilibrium and buffer solutions in a biological setting.
Chemistry Collective
Chem Collective: Strong Acid and Base Problems
Textbook-style strong acid and base problems that can be checked using the Virtual Lab.