# What coefficients balance Al(OH)_3 -> Al_2O_3 + H_2O?

$2 A l {\left(O H\right)}_{3} \rightarrow A {l}_{2} {O}_{3} + 3 {H}_{2} O$
On the the left side, there are $1 A l , 3 O , \mathmr{and} 3 H$ originaly and $2 A l , 4 O , \mathmr{and} 2 H$. Since both sides need to have the same amount of each element, both sides need to have $2 A l , 6 O , \mathmr{and} 6 H$. This is why there are 3 water molecules, two $A l {\left(O H\right)}_{3}$ molecules, and 1 molecule of $A {l}_{2} {O}_{3}$ to have the equation balanced.