When iron rusts and forms iron oxide, the iron oxide has more mass than the iron. Which statement correctly explains this difference in mass?

Question

A. There are more iron atoms in iron oxide than in pure iron
B. Iron oxide has oxygen atoms, and pure iron does not
C. The iron atoms in iron have more mass than pure iron
D. The oxygen atoms in iron oxide have more mass than the iron atoms in pure iron

Answer 1

The correct statement that explains the difference in mass when iron rusts and forms iron oxide is:

B. Iron oxide has oxygen atoms, and pure iron does not.

This is because when iron rusts, it combines with oxygen from the environment to form iron oxide, which adds mass to the resulting compound.