List two chemical reactions that resulted in a colored precipitate – look for a red, orange, or yellow product. Be sure to list the names of all reactants and products for both reactions. Consider all the reactions from the lab that gave a colored precipitate (red, orange or yellow). What ion or ions do these reactions have in common?Answer:(7 points) Please answer the following questions based on your own lab results. ScoreList two chemical reactions from this lab that resulted in a white precipitate. For each reaction, list the names of all reactants and products. Look over your results carefully – what ion or ions do the reactions that resulted in a white precipitate have in common with each other?Answer:(6 points)ScoreHow many of the chemical reactions performed in the lab resulted in a precipitate? How many reactions did not? Define the term double-displacement in your own words, then make a general statement about the interaction of aqueous ionic compounds using the terms double-displacement reaction and precipitate.Answer:Your Score___ of 20
Lab 4 – Materials and Lab Information
If you are missing materials from your lab kit, notify your teacher immediately and call 1-866-K12CARE so that K12 can send you the missing item(s).
Supplied in Kit:
- hand lens
- goggles, safety
- gloves, disposable
- microplate, 24 well
- barium nitrate (10 mL, 0.1 M)
- silver nitrate (10 mL, 0.2 M)
- sodium sulfate (20 mL, 0.1 M)
- barium chloride (20 mL, 0.1 M)
- sodium chromate (10 mL, 0.2 M) aluminum sulfate (20 mL, 0.1 M)
- sodium hydroxide (10 mL, 0.2 M)
- aluminum chloride (10 mL, 0.1 M)
- magnesium nitrate (20 mL, 0.1 M)
- magnesium sulfate (10 mL, 0.1 M)
- magnesium chloride (20 mL, 0.1 M)
- potassium chromate (10 mL, 0.2 M)
- potassium chloride (10 mL, 0.1 M)
Also Needed (Supplied by student):
- toothpicks 24
- notebook/printer paper
HYPOTHESIZE: Before you begin the lab, you should make a hypothesis about the lab. Write a hypothesis that describes how solutions may differ in terms of their ability to form a precipitate when mixed with other solutions. Write your hypothesis as an if-then statement, and base it on your everyday observations.
Microplate Chemical Combinations: **Wash Microplate between each set!
Set 1
| 1 | 2 | 3 | 4 | 5 | 6 |
A | Ba(NO3)2 Na2SO4 | Ba(NO3)2 Al2(SO4)3 | Ba(NO3)2 Mg(NO3)2 | Ba(NO3)2 MgCl2 | Ba(NO3)2 AlCl3 | X |
B | Na2SO4 Al2(SO4)3 | Na2SO4 Mg(NO3)2 | Na2SO4 MgCl2 | Na2SO4 AlCl3 | X | X |
C | Al2(SO4)3 Mg(NO3)2 | Al2(SO4)3 MgCl2 | Al2(SO4)3 AlCl3 | X | X | X |
D | Mg(NO3)2 MgCl2 | Mg(NO3)2 AlCl3 | MgCl2 AlCl3 | X | X | X |
Set 2
| 1 | 2 | 3 | 4 | 5 | 6 |
A | KCl MgCl2 | KCl Na2SO4 | KCl NaOH | KCl BaCl2 | KCl MgSO4 | X |
B | MgCl2 Na2SO4 | MgCl2 NaOH | MgCl2 BaCl2 | MgCl2 MgSO4 | X | X |
C | Na2SO4 NaOH | Na2SO4 BaCl2 | Na2SO4 MgSO4 | X | X | X |
D | NaOH BaCl2 | NaOH MgSO4 | BaCl2 MgSO4 | X | X | X |
Set 3
| 1 | 2 | 3 | 4 | 5 | 6 |
A | BaCl2 Mg(NO3)2 | BaCl2 Na2CrO4 | BaCl2 Al2(SO4)3 | BaCl2 K2CrO4 | BaCl2 AgNO3 | X |
B | Mg(NO3)2 Na2CrO4 | Mg(NO3)2 Al2(SO4)3 | Mg(NO3)2 K2CrO4 | Mg(NO3)2 AgNO3 | X | X |
C | Na2CrO4 Al2(SO4)3 | Na2CrO4 K2CrO4 | Na2CrO4 AgNO3 | X | X | X |
D | Al2(SO4)3 AgNO3 | Al2(SO4)3 K2CrO4 | K2CrO4 AgNO3 | X | X | X |
General Notes:
- Read through all of the lab information in the course and in the lab manual before you begin!
- This lab will be completed and graded as a lab report. Please ignore any mention in the course of a discussion.
- In between each ‘set’ of the lab and at the end of the lab, make sure you clean your microplate thoroughly! Use a soapy water solution and q-tips to clean each well. Leave the microplate upside down to dry. Do not put your microplate in the dishwasher!
- LAB SAFETY: make sure the room is well ventilated; wear gloves & goggles; do not taste, ingest, or smell chemicals; make sure you have an adult to supervise the experiment; make sure you have running water in the room where you do the lab; know your local poison control #; do not carry out the lab around any heat sources
Data Collection: Make charts like the following to help you record your observations.
Set | Well | Solution A | Solution B | Color change (Y/N) | Precipitate Formed (Y/N) |
1 | 1A | Ba(NO3)2 | Na2SO4 |
|
|
1 | 2A | Ba(NO3)2 | Al2(SO4)3 |
|
|
1 | 3A | Ba(NO3)2 | Mg(NO3)2 |
|
|
Continue for all combinations from all sets
Questions to Answer – Answers will be typed into the lab sheet and saved/submitted as a Word document into the Dropbox.
BE VERY THOROUGH IN YOUR RESPONSES!!!!
- List at least two chemical reactions that resulted in either a yellow, orange, or red precipitate. For each of these reactions, list the possible chemical name of the precipitate and other product (list the names of both products for each reaction). What do these reactions, and the others with yellow, orange, or red precipitates, have in common?
- List at least two chemical reactions that resulted in a white precipitate. For each of these reactions, list the possible chemical name of the precipitate and other product (list the names of both products for each reaction). What do these reactions, and the others with white precipitates have in common?
- Of all the reactions you performed, how many resulted in a precipitate and how many did not? Make a general statement about the interaction of aqueous ionic compounds, using the term doubledisplacement reaction.
Once you have answered the above questions, open the lab report sheet
(found in lesson ‘Lab: Salts 1’) and type in your answers to the questions on the lab report. Save your file and submit your final lab report as a Word document into the Dropbox.
Make sure you are very thorough in answering the questions on the final lab report!