Chemistry Year 12 - Module 8 - Lesson 2
Gravimetric Analysis
1. Key Ideas
A water authority receives an industrial wastewater sample and needs to know whether sulfate levels are too high for safe discharge. No fancy colour change, no spectrometer screen, just chemistry: dissolve, precipitate, filter, dry, weigh, and let the mass reveal what was present.
- The sequence dissolve → precipitate → filter → dry → weigh
- Why an insoluble, pure precipitate is essential for reliable gravimetric analysis
2. Success Criteria
By the end, you should be able to:
- The sequence dissolve → precipitate → filter → dry → weigh
- How gravimetric analysis determines the amount of analyte from precipitate mass
- Which precipitating agents are suitable for common ions
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. Explain this lesson goal in your own words: "The sequence dissolve → precipitate → filter → dry → weigh". Use one specific example from the lesson.
2. Apply this idea to a new example: "How gravimetric analysis determines the amount of analyte from precipitate mass". Show your reasoning clearly.
3. Analyse why this idea matters for understanding Gravimetric Analysis: "Which precipitating agents are suitable for common ions".
6. Extend: Apply the Idea
A student gives a memorised answer about Gravimetric Analysis but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Gravimetric Analysis?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Gravimetric Analysis?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.