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:
- Write balanced molecular equation.
- Determine molarity of solutions.
- Execute mole ratio calculations based on the reaction.
- 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.