Aluminum metal is used in many products. It quickly reacts with oxygen in the reaction 4Al (s) + 3O2 (g)--> 2Al2O3 (s). Which component is different on each side of the equation arrow?

a. mass
b. atoms
c. moles
d. all are the same.

1 answer

4Al (s) + 3O2 (g)--> 2Al2O3 (s)

The mass on each side must be the same (conservation of mass) which means that the number of each type of atom is the same on each side.

From the equation you can see that there are 7 moles on the LHS and 2 moles on the RHS. So are moles the same on each side?