An atom of element X has an atomic mass of about 40; after reacting with a second atom of X, a different element (called Y) with an atomic mass of 80 is produced. What type of reaction is this?
a. fusion
b. fission
c. combustion
d. synthesis
The answer is a. fusion. The reaction formed a different element, so this is not a chemical reaction. Then c and d are not correct. Two atoms form one atom, so it is fusion.
