What is the formula for magnetite?
magnetite is Fe3O4 and they can also call it ferrous-ferric oxide
Convert the percent to mass, and then the mass to moles: (72.4g Fe)/(1 mol Fe/55.85g Fe) 1.30 mol Fe (27.6g O)/(1 mol O/16g O) 1.73 mol O Divide by the smallest number of moles: 1.30 mol Fe/1.30 mol 1 1.73 mol O/1.30 mol 1.33 Multiply until you get a whole number Fe: 1 x 3 3 O: 1.33 x 3 4 So there is 3 iron, and 4 oxygen Thus, the formula is ---- Fe3O4
First possibility that comes to mind is they did not get the bead seated all the way around. You should be able to tell by looking. Most tires have a line that runs about 1/8 away from the rim all the way around. If that line goes behind the rim, the bead is not seated.
I have read the other answers and by all means check to see if there are any loose bolts. But, my guess is that in pushing a flat tire 2 miles that the tire is now out of round. But, in the future you can change the tire yourself if it is a tube type. Dennis kirk is a good place to buy tires, innertubes and you can even learn how to balance a tire yourself. I have learned that I can do most repairs myself. It is a good idea to learn as much as you can about maintaining your own bike. I have a honda rebel that has an out of round tire. I figure that since I only ride this bike around town that it is not that big of a deal. But, I could see if you go at highway speed you would want to replace the tire.
If you assume you have 100 grams of magnetite, then you can divide the 72.6g by its atomic weight of approx. 55.8g/mole. Do the same for the oxygen's 27.6g by dividing by 16 g/mole and then ratio the results and you will find the ratio of Fe to O is 3 to 4. So the formula is Fe3O4. This may look weird because it does not give a whole number for the oxidation number of iron, but it works out this way because it is a mixture of FeO and Fe2O3.
