To determine which component is different on each side of the equation, let's analyze the chemical reaction:
4Al (s) + 3O2 (g) -> 2Al2O3 (s)
The equation represents a chemical reaction between aluminum metal (Al) and oxygen gas (O2) to form aluminum oxide (Al2O3). The numbers in front of the chemical symbols represent the coefficients, which indicate the relative number of moles or molecules involved in the reaction.
On the left side of the arrow, we have 4 atoms of aluminum (4Al) and 3 molecules of oxygen gas (3O2). On the right side of the arrow, we have 2 moles of aluminum oxide (2Al2O3).
From this analysis, we can conclude that the component that is different on each side of the equation is the moles, as the number of moles of reactants and products does not match.
Therefore, the correct answer is:
c. moles