To find the amount of oxygen that reacted with the iron, we need to determine the difference in mass between the iron and the rust formed.
Given: Mass of iron (Fe) = 4 g Mass of rust (Fe2O3) = 10 g
Since rust is an oxide of iron, the formula for rust is Fe2O3. From this information, we can determine the molecular masses of iron and oxygen.
Atomic mass of iron (Fe) = 55.85 g/mol Atomic mass of oxygen (O) = 16 g/mol
The molecular mass of rust (Fe2O3) can be calculated as follows: 2(Fe) + 3(O) = 2(55.85 g/mol) + 3(16 g/mol) = 111.7 g/mol + 48 g/mol = 159.7 g/mol
Now, we can find the amount of oxygen that reacted with the iron by subtracting the mass of iron from the mass of rust: Mass of oxygen = Mass of rust - Mass of iron = 10 g - 4 g = 6 g
Therefore, 6 grams of oxygen reacted with 4 grams of iron to form 10 grams of rust.