How to identify an unknown metal?

Question

Breaking my brain to figure this one out:

A 2.00g sample of an unknown metal, M, was completely burned in excess O2 to yield 0.02224 mol of the metal oxide M2O2, what is the unknown metal?

So far, I've run in circles and only managed to figure out that the reaction would have to be something like 4M+3O2--> 2M2O3 any hints as to how to begin solving this would be greatly appreciated.

I just noticed I put in a typo in the problem, it yielded 0.02224 mol of M2O3, not M2O2... Sorry.

Answer 1

Ok, which is it M2O3 or M2O2? Your question has both of those as the product of the reaction.

You know how many moles of product you end up with. You know how many grams of metal you began with. You figure out the chemical formula and figure out how many moles of the metal you started with. Then go to the periodic table and see which element will have that number of moles equal to 2 grams.

Ok, here is what I have

From the equation it takes 2 moles of M to make 1 mole of M2O3. You have .02224 moles of M2O3. That means that you need .04448 moles of M. We know that we started with 2 grams of M. So 2 grams of M will be .04448 moles of M. I divided 2 by .04448 to find the grams per mole for the metal. That came to 44.964 grams per mole. I went to a periodic table and found that Scandium has 44.955 grams per mole. That is the closest match on the table that I could find. So, I am going to go with Scandium.

Answer 2

Density is a very reliable place to start (assuming that the metallic is a "organic" metallic). you ought to degree hardness. in case you have an somewhat hardness tester, this is extremely straight forward. in case you haven't any longer have been given a hardness tester, you need to use the Mohr Hardness scale, from talc to diamond. Google it. you additionally can use magnetism yet, except you have a magnetometer (an tool for measuring magnetic fields) this may be regularly a "confident/no" measurement. in case you have a volt meter, you ought to degree electric resistance and convert that to electric resistivity. google resistivity. reliable luck