Titrations and Rates of Reaction

The host, Melissa Marival, warmly welcomes viewers to her live show where she answers pre-submitted questions. She expresses excitement about the number of participants and encourages new viewers to engage. Melissa explains the format of the show, where she prepares detailed lessons based on the questions received. She emphasizes the value of the free tutoring provided and recommends tweeting questions ahead of time to ensure they are addressed on the show. She also mentions additional resources available in the description box, including online tutoring and homework help services.

Melissa delves into the topic of the day, titrations and rates of reaction. She explains that titrations involve an acid-base neutralization reaction and uses an indicator, like phenolphthalein, to signal when neutralization is reached. She shares a tip for accurately identifying the faint pink color that indicates the equivalence point. Melissa also discusses the importance of distinguishing between strong and weak acids and bases, as it affects the type of titration being performed. She provides a brief overview of how to calculate the equivalence point and set up the balanced equation for the reaction.

Melissa focuses on the strong acid-strong base titration, explaining how to determine the pH at different volumes. She outlines the process of finding the equivalence point by using the molarity of the acid and base, and emphasizes the importance of understanding the balanced chemical equation. Melissa also explains how to calculate the moles of the acid and base involved in the reaction and how to use this information to find the pH at various stages of the titration. She notes that the pH will be 7 at the equivalence point for a strong acid-strong base titration.

Shifting to weak acid-strong base titrations, Melissa explains the process of identifying the equivalence point and the use of an ICE (Initial, Change, Equilibrium) table. She highlights the importance of understanding the dissociation constant (Ka) for weak acids and how it differs from strong acids. Melissa also introduces the concept of the half-equivalence point, where the pH equals the pKa, and explains how to use this information to simplify calculations. She emphasizes the need to adjust calculations based on the strength of the acid and base involved.

Melissa addresses the concept of reaction rates and orders, explaining how changes in concentration of reactants affect the rate of reaction. She discusses zero, first, and second order reactions, and how they can be identified by comparing initial rates. She also talks about how keeping the concentration of one reactant constant can help determine the reaction order of another. Melissa suggests using the provided data to calculate the rate law and further understand the dependencies between reactants and reaction rates.

In the concluding segment, Melissa wraps up the lesson and encourages viewers to tweet their questions for future live shows. She reminds viewers to submit questions ahead of time and to check the description box for additional resources, including the chemistry survival guide and links to online tutoring and homework help services. Melissa also mentions her affiliation with check study, a resource she personally found helpful during her college years, and discloses her participation in their affiliate program. She ends the show on a positive note, thanking viewers for their participation and looking forward to the next live show.