Al + H2SO4 = Al2(SO4)3 + H2 single replacement
We still need to balance it though al needs a 2
2Al + H2SO4 = Al2(SO4)3 + H2
SO4 needs a 3 so
2Al + 3H2SO4 = Al2(SO4)3 + H2
now the H on the right needs a 3 to be equal to left h's 6
2Al + 3H2SO4 = Al2(SO4)3 + 3H2
Balanced.
C5H12 + O2 = H2O + CO2 double replacement
so we need 5 c so
C5H12 + O2 = H2O + 5CO2
now we need 6 h's to equal left h's 12
C5H12 + O2 = 6H2O + 5CO2
the left O needs an 8 to equal right side
C5H12 + 8O2 = 6H2O + 5CO2
Balanced
