What is the formula for magnetite?
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.
magnetite is Fe3O4 and they can also call it ferrous-ferric oxide
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.
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.
