Four bottles, labeled A through D, each containing about 5 grams of finely powdered white substance are found in a lab. Near the bottles are four labels specifying high purity and indicating that substances are glucose (C6H12O6), sodium chloride (NaCl), aluminum oxide (Al2O3), and zinc sulfate (ZnSO4). These labels belong to the bottles and each bottle has only one substance.
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Describe tests you would use to help find which label goes to which bottle. Then figure out what substance actually goes to which of the four bottles and explain.
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I'm so confused on how to do this. Please help me asap! THANKS!!!
What do you know about the properties of these four substances?
Glucose, NaCl, and ZnSO4 are soluble in water. Al2O3 is not. One down.
Of the solutions, glucose does not conduct electricity. NaCl and ZnSO4 do. Two down.
ZnSO4 + NaOH produces Zn(OH)2, an insoluble ppt. NaCl has no reaction with NaCl. Three and four down.
Post any questions you have about this process. It is important that you are able to apply chemical knowledge about ions and compounds in solution. In the old days we taught qualitative chemistry. Qualitative analysis is not emphasized these days.
So would all I need to solve this is to know the solulubility rules?
Yes, knowing the solubility rules is a good start. You may also need to know the reactions of the substances with other chemicals, such as NaOH, to help you identify them.
Knowing the solubility rules will definitely help you in solving this problem. By understanding the solubility of each substance in water, you can perform tests to determine the identity of each substance in the bottles. Here's how you can approach it:
1. Test for solubility: Take a small amount of the substance from bottle A and dissolve it in water. If it is soluble, it could be glucose, NaCl, or ZnSO4. Repeat this test with substances from bottles B, C, and D as well.
2. Test for electrical conductivity: Dissolve a small amount of the substance from bottle A in water and check if the solution conducts electricity using a conductivity tester. If it does not conduct electricity, it is likely to be glucose. Repeat this test with substances from bottles B, C, and D.
3. Test for precipitation: Mix a solution of NaOH with a small amount of the substance from bottle A. If it forms a precipitate (a solid that settles at the bottom), it is likely to be ZnSO4. Repeat this test with substances from bottles B, C, and D.
4. By process of elimination, you can now identify the substances in each bottle. The substance that is soluble in water but does not conduct electricity must be glucose (C6H12O6). The substance that is soluble in water and conducts electricity must be NaCl (sodium chloride). The substance that is insoluble in water and forms a precipitate with NaOH must be ZnSO4 (zinc sulfate). Therefore, the remaining substance (which is insoluble in water and does not react with NaOH) must be Al2O3 (aluminum oxide).
So, based on these tests, bottle A contains glucose, bottle B contains sodium chloride, bottle C contains aluminum oxide, and bottle D contains zinc sulfate.
Remember, this is a hypothetical situation, and in a real lab setting, you would need to perform more accurate and precise tests, such as melting point determination or spectroscopic analysis, to confirm the identity of the substances.
Knowing the solubility rules is definitely helpful in solving this problem. By understanding the solubility properties of each substance, you can perform tests to identify which label corresponds to which bottle. Here is a step-by-step guide to help you find the correct labeling for each bottle:
Step 1: Establish solubility in water:
- Take a small amount of substance from the first bottle (labeled A) and dissolve it in water.
- If the substance dissolves completely, it is either glucose or NaCl, as both are soluble in water.
- If the substance does not dissolve, it is either aluminum oxide or zinc sulfate, as they are not soluble in water.
Step 2: Conductivity test:
- Take a small amount of the dissolved substance (from Step 1) and test its conductivity using a conductivity tester.
- If the solution does not conduct electricity, it is glucose.
- If the solution conducts electricity, it is NaCl or ZnSO4.
Step 3: Distinguishing between NaCl and ZnSO4:
- Take a small amount of the conductive solution (from Step 2) and add a few drops of NaOH (sodium hydroxide) to it.
- If a white precipitate (insoluble ppt) forms, the solution contains ZnSO4.
- If there is no reaction or precipitate, the solution contains NaCl.
After conducting these tests, you should be able to determine the labeling for each bottle:
Bottle A contains glucose (C6H12O6), as it dissolves in water but does not conduct electricity.
Bottle B contains NaCl (sodium chloride), as it dissolves in water and conducts electricity. It does not react with NaOH.
Bottle C contains Al2O3 (aluminum oxide), as it does not dissolve in water.
Bottle D contains ZnSO4 (zinc sulfate), as it dissolves in water and conducts electricity. It forms a white precipitate with NaOH.
Remember to handle the substances and chemicals used in these tests safely and follow proper lab protocols.
Knowing the solubility rules is indeed important to help solve this problem. In this case, you need to perform a series of tests to identify the substance in each bottle. Here's a step-by-step approach to solve this:
1. Test for solubility: Dissolve a small amount of substance from each bottle in water separately. Glucose, NaCl, and ZnSO4 will all dissolve in water, while Al2O3 will not.
- If all substances dissolve, move to the next test.
- If any substance does not dissolve, you can confirm that the bottle with that substance is labeled Al2O3.
2. Test for electrical conductivity: Take the solutions obtained in step 1 and use a conductivity tester to check which ones conduct electricity. Glucose will not conduct electricity, while NaCl and ZnSO4 will.
- If all solutions conduct electricity, move to the next test.
- If one solution does not conduct electricity, you can confirm that the bottle with that substance is labeled glucose.
3. Test for precipitation reaction: Take the remaining solutions (containing NaCl and ZnSO4) and add a few drops of NaOH (sodium hydroxide) separately to each solution. NaCl will not produce any visible reaction, while ZnSO4 will produce a white precipitate of Zn(OH)2.
- If one solution produces a white precipitate, you can confirm that the bottle with that substance is labeled ZnSO4.
- The remaining bottle will contain NaCl.
To summarize the results based on the tests:
- Bottle A: Al2O3 (based on insolubility in water test)
- Bottle B: Glucose (based on lack of electrical conductivity)
- Bottle C: ZnSO4 (based on precipitation reaction test)
- Bottle D: NaCl (remaining substance)
Keep in mind that this is a logical deduction based on the given information and the results of the tests.