I need help with figuring out an appropriate way to do this sort of lab: how to determine an unknown compound.
With this one however, the teacher just gave us a white powdered compound - and asks us to figure out how to identify it using ANY lab procedures.
He gave hints that the powder DOES NOT react with water and it can be a SALT or just molecules.
I thought of doing a flame test, qualitative, finding molar mass, etc... but I don't know what to do specifically. Help?
Thank you!
Is it just one compound? Is the compound an inorganic compound?
Color can give a hint.
A flame test is good if you know it's just one compound. Sometimes, but not always of course, it can identify the metal.
See if it's soluble in water. Then look at the table of solubilities. That will eliminate many compounds.
See it it reacts with dilute HNO3, HCl. dilute H2SO4? If it dissolves, does it do so with the evolution of a gas. If a gas, what's the odor of the gas? Again, consult with the solubility table for nitrates, chlorides, and sulfates. This should get you started.
[Note: For example, if it dissolves in water and a ppt forms with dilute HCl, you know immediately that it is one of three things. It must be a silver compound, a lead compound, or mercury(I) compound for those chlorides are insoluble in water. AgNO3, for exampl would be soluble in water but insoluble in dilute HCl.] I think what your prof wants you to do is to call on your knowledge of chemistry to create a reasonable procedure for systematic identification of ions.
[
To determine the identity of an unknown compound, there are several lab procedures you can consider. Based on the information provided by your teacher, here is a step-by-step approach to follow:
1. Conduct a visual examination: Observe the appearance of the white powdered compound. Note its texture, color, and any recognizable features. This can provide initial clues about the compound's nature.
2. Perform a solubility test: Dissolve a small amount of the powder in a variety of solvents, such as water, ethanol, or acetone. If the compound is soluble in a specific solvent, it can provide information about its chemical nature.
3. Conduct a flame test: Take a small sample of the compound and place it in a flame. Observe the color of the flame produced. Different compounds emit characteristic colors when heated. This can provide clues about the presence of certain elements.
4. Perform a molar mass determination: Calculate the molar mass of the compound using various methods. This could involve techniques like vapor density determination, freezing point depression, or colligative properties. Compare the calculated molar mass with known values for different compounds to narrow down the possibilities.
5. Use qualitative analysis techniques: Perform tests or experiments to identify specific functional groups or ions present in the compound. These tests could include pH testing, precipitation reactions, or acid-base titrations. The results will help in identifying the compound's composition.
6. Utilize spectroscopy techniques: Employ spectroscopic methods such as infrared spectroscopy (IR), nuclear magnetic resonance (NMR), or mass spectrometry (MS). These techniques can provide detailed information about the compound's structure, functional groups, and molecular composition.
Remember, it may not be necessary to use all of these techniques. Start with the most accessible and straightforward tests, and based on the obtained results, proceed with further analysis. It's also important to consult relevant literature, such as chemical reference books or online databases, to compare your findings with known compounds and assist in identification.