2 Iron(III) oxide (Fe2O3) is reduced by carbon on heating to give iron metal (Fe) and carbon dioxide (CO2). (Ar values Fe 56, C 12,0 16)
When 480 g of Fe2O3 is heated with carbon, 336 g of Fe and 198 g of CO2 are produced.
Use the Law of Conservation of Mass to work out the mass of carbon that
reacted.
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considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

im doing test rn im going with 2 but ill give answer if itss wrong,   : )