How would you balance Al + H2SO4 = Al2(SO4)3 + H2?
2Al + 3H2SO4 = Al2(SO4)3 + 3H2
When balancing chemical equations I always start with oxygen and identify which compound has the most, which in our case is Al2(SO4)3. So because we have 4 O in SO4, and there are 3 of moles of SO4, so we multiple 4x3=12. So now, go to the opposite compound with O (H2SO4) and manipulate it to even out the O, in this case multiple by 3. Now we have 12 O on each side, 3 S on each side, and all we have to do here is multiply the lone Al on the reactants side by 2, and then because we multiplied H2SO4 by 3, we have 6 H on that side, so just multiple H2 on the other side by 3 as well and your done