2.2 Analytical Chemistry: Identify Ions Present in Solution
achievement_standard_ch_2-2_specifications.pdf | |
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Key Ideas:
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Assessment information:
The assessment for this standard will include both practical and written portions. You will be provided with several solutions and asked to identify either the cation OR the anion present using techniques you have learned during class. During your testing, you will need to identify any precipitates and/or complex ions formed and write balanced equations for the reactions involved. |
Keep this ion list for the rest of the year. It will be your friend.
polyatomic_ions_reference_list.pdf | |
File Size: | 424 kb |
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2.2.1 Coloured Ions
Lesson overview:
Metals appear and behave differently when they are ions in solution then when they are solid. The colour of the solution can sometimes be used as a clue when identifying unknown solutions. You should be able to:
In Class Activity: Make a table similar to page 35 in text and identify the colour of solutions and respective ions provided in class.
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2.2.2 Solubility Rules and Ionic Equations
Lesson Overview:
Some ionic compounds are soluble in water while others are not. When two solutions are mixed, two of the ions present in the new solution may form an insoluble salt resulting in a precipitate. You should be able to:
Homework (to be started in class):
Notes
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2.2.3 Predicting Precipitation Reactions
Lesson Overview:
Solubility rules can be used to predict whether or not two solutions will result in a precipitation reaction, and what the precipitate will be. You should be able to:
In class activity:
Homework: Worksheet Handouts (handed out in class, answers included in attachment below)
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2.2.4 Identifying unknown solutions
Lesson Overview:
When identifying unknown ions present in a solution, we will focus on either the anion OR the cation, never both at the same time. You will need to use your knowledge of solubility rules and precipitation reactions to devise and carry out a plan to identify unknown solutions.
When identifying unknown ions present in a solution, we will focus on either the anion OR the cation, never both at the same time. You will need to use your knowledge of solubility rules and precipitation reactions to devise and carry out a plan to identify unknown solutions.
In class activity (2 days):
- Practical 4.2 (pg 39-40)
- Write out your own directions on how to test for each anion
- Write out all observations for all tests carried out
- Write balanced equations for all reactions
2.2.5 Identifying Anions
Lesson Overview:
Use your knowledge of identification techniques and the flowchart provided to identify all six anions in a mock-exam setting. By the end of this section you should be able to:
(Missing answer sheet document) |
2.2.6 Complex Ions
***Note: This is an excellence level skill.
Lesson Overview: If a new chemical is added to a precipitate and the precipitate dissolves, a soluble complex ion is formed
You should be able to:
Homework 2.2.6: Select four different anions that you tested for in class. Use the provided assessment chart to show how you identified each ion and the equations used.
Refer to the attached document for more on complex ions
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The first ~2:30 of this video provide a nice description of complex ion formation. Everything after that is beyond the scope of this unit (ie. K values, equilibrium, etc)
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2.2.7 Identifying Cations
Lesson Overview:
Use the skills you have learned while identifying unknown anions and apply them to cations. You should also identify where complex ions are formed. You should be able to:
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Worksheets for more Practice
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testing_for_ions.docx | |
File Size: | 15 kb |
File Type: | docx |
unknown_ion_scenarios.docx | |
File Size: | 177 kb |
File Type: | docx |
2.2.8 Exam Prep
Ions in Solution Weekend Study Guide
•Go through the flow chart and write the steps and equations, including complex ions, for every single ion
•Make sure you know what salt is formed in every ppt reaction
•Know what happens when you add NH3 and get a ppt with OH-
•Use the text book to check your equations but be aware that they may use different pathways
Points to remember when testing solutions
•Write the colour of the ppt or solution
•Any time there is a CHANGE, there is an EQUATION (no change = no equation)
•Make sure you name the salt form in a ppt reaction
•Use a small test sample so if you need to dissolve a ppt, there isn’t too much. And give them time.
•You may not know what salt is formed when you first see it, remember to go back and write the equation once you identify the ion.
•Go through the flow chart and write the steps and equations, including complex ions, for every single ion
•Make sure you know what salt is formed in every ppt reaction
•Know what happens when you add NH3 and get a ppt with OH-
•Use the text book to check your equations but be aware that they may use different pathways
Points to remember when testing solutions
•Write the colour of the ppt or solution
•Any time there is a CHANGE, there is an EQUATION (no change = no equation)
•Make sure you name the salt form in a ppt reaction
•Use a small test sample so if you need to dissolve a ppt, there isn’t too much. And give them time.
•You may not know what salt is formed when you first see it, remember to go back and write the equation once you identify the ion.