C12 - Chemical Analysis
Independent learning
Introduction
In this topic you will look at laboratory tests that analysts have developed to detect specific chemicals. The tests are based on reactions that produce a gas with distinctive properties, or a colour change or an insoluble solid that appears as a precipitate.
Instrumental methods provide fast, sensitive and accurate means of analysing chemicals, and are particularly useful when the amount of chemical being analysed is small. Forensic scientists and drug control scientists rely on such instrumental methods in their work.
Specification links:
Task 1: Know
Task 1a: Use look, cover, write, check and quizlet to learn the answers to the core questions and the keywords for this topic.
Learn
Task 2: Pure and impure substances
Task 2b: Make notes that:
Define pure and impure substances.
Define formulations.
Describe the difference between pure substances, impure substances, and formulations.
Explain how melting point and boiling point data can be used to determine the purity of a substance.
Explain uses of formulations.
Complete the questions on slide 21.
Task 2c: Complete and self mark the exam questions
Task 3: Chromatography required practical
Task 3b: Make notes that:
Plan and carry out a method for paper chromatography.
Describe a use of chromatography.
Explain how chromatography separates solutes.
Calculate Rf values from given data.
Explain why different substances and different conditions will have different Rf values.
Task 3c: Complete the exam questions
Task 4: Gas tests
Task 4b: Make notes that:
Describe how to carry out the laboratory test for hydrogen.
Describe how to carry out the laboratory test for oxygen.
Describe how to carry out the laboratory test for carbon dioxide.
Describe how to safely carry out the laboratory test for chlorine gas.
Task 4c: Complete the exam questions
Set 2 & 3: Go to task 8 now
Set 1 only. - Complete the progress quiz
Task 5: Tests for positive ions - Set 1 only
Task 5b: Make notes that:
Describe how to carry out flame tests for positive ions.
Explain why a flame test cannot be used to identify a mixture of metal solutions.
Give balanced ionic equations, including state symbols for the production of an insoluble metal hydroxide.
Explain why iron(II) hydroxide solution often changes colour when it stands in air.
Task 5c: Complete exam question
Task 6: Tests for negative ions - Set 1 only
Task 6b: Make notes that:
Describe how to carry out tests for halides.
Describe how to carry out tests for carbonates.
Describe how to carry out tests for sulfates.
Give balanced symbol equations, including state symbols for the reactions in the simple laboratory tests for carbonate, halide, or sulfate ions.
Explain in detail how to identify a compound from the results of simple laboratory tests.
Task 6c: Complete and self mark the exam questions
Task 7: Spectroscopy - Set 1 only
Task 7b: Make notes that:
Compare instrumental techniques with simple laboratory tests.
Describe the main processes of flame emission spectroscopy.
Explain how flame emission spectroscopy is an improvement on flame tests.
Task 7c: Complete the literacy worksheet
Task 8: Summary
Task 8c: Complete the seneca learning unit for your set.
Task 8d: Make a mind map or other revision resources and add them to your revision folder