Teaching Technology in Chemistry Education

  • Discussion during a meeting with the dean about teaching technology in online settings during COVID-19.
    • Mention of a coworker, Brett May, who innovatively used a laboratory ring stand to improve online teaching.
    • Set up camera on a ring stand to write on a piece of paper during Zoom sessions.
    • Highlighted that this simple setup was effective, cost nothing, and was created quickly (in 10 minutes).

Transition to Chapter 4

  • Observation of benefits of ebooks compared to paper books:

    • Text in ebooks spans the entire page, has increased visibility for easier reading.
    • Chemical reactions are presented in a more continuous format, less fragmented than in paper books.
  • Reminder about upcoming quiz on Friday concerning homework assigned on Monday:

    • Quiz will cover approximately one and a half lectures focusing on baking solutions and multi-liter topics.

Homework and Practice on Solubility Rules

  • Importance of having the solubility rules list available for reference during quizzes.
    • Encouraged students to memorize these rules as the course progresses.
    • Students will engage in practice writing chemical formulas, which aids in understanding reactions.

Precipitation Reactions Example: Follow-up 4.7a

  • Discussion of a precipitation reaction between iron(III) chloride (FeCl₃) and cesium phosphate.
    • Reaction outline:
    • Reactants: FeCl₃ + Cs₃PO₄
    • Products: Cesium chloride (CsCl) + Iron(III) phosphate (FePO₄)
    • Discussed the process of swapping cations and anions:
      • Metathesis concept: exchange of ions between the reactants.

Balancing Charges

  • Iron's charge: +3 (Fe³⁺), Phosphate's charge: -3 (PO₄³⁻)
    • Shows that the charge is balanced in the products.
    • Substituted other salts to represent soluble or insoluble products based on solubility rules.

Analyzing Solubility

  • Experience with solubility rules:
    • First rule: All compounds of group one cations (Li⁺, Na⁺, K⁺, etc.) are soluble.
    • Example: Cesium (Cs⁺) is in group one, hence the compound is soluble.
    • Second rule: Carbonates and phosphates generally are insoluble, but exceptions exist for group one and ammonium compounds.

Importance of Solubility Rules

  • Students encouraged to refer to the order of importance of solubility rules while analyzing reactions.
    • Discussed exceptions based on empirical observations and exceptions within the solubility rules.

Example Reactions and Their Analysis

  • Discussion of various chemical reactions including:
    • Hydroxide reacting with cadmium nitrate to yield cadmium hydroxide, highlighting the balance of charges.
    • Notable solubility of sodium compounds including sodium acetate and nitrates.
    • Notations about equilibria and how to determine solid, liquid, or gas states in net reactions.

Preparation for Quizzes and Assessments

  • Emphasized the significance of being thorough in writing reactions and identifying states (s, l, g).
    • Students should practice entering charges, labels, and ensuring proper balancing when working on quizzes.
    • Total ionic reactions showcased as requiring detailed interaction recording.

Calculating Molarity and Volume in Reactions

  • Discussion of water softening as a practical application of chemistry in real life.
    • Boiling scale formation due to calcium ion precipitation.
    • Example calculation provided for determining the volume needed for sodium phosphate to react with calcium chloride:
    • Process explained step-by-step including:
      1. Write balanced molecular equation.
      2. Determine molarity of solutions.
      3. Execute mole ratio calculations based on the reaction.
      4. Compute final volume from moles involved.

Test Averages and Grading Philosophy

  • Conversation on test averages following recent assessments.
    • Noted average test score as a metric, but emphasized individual performance variance and study habits.
    • Encouraged students to seek additional help and tutoring to improve performance.

Key Takeaways

  • Students reminded that understanding chemical reactions and applying solubility rules requires repetition and practice.
  • Direct engagement with problems and using available resources (e.g., periodic table, solubility tables) is vital for success.