How do you balance BaCl_2 + Al_2S_3 -> BaS + AlCl_3?

1 Answer
Apr 15, 2016

Create an equation for each of the elements, then set one of them and solve for the others. Answer is:

3BaCl_2+Al_2S_3->3BaS+2AlCl_3

Explanation:

Let the four balancing factors be a b c d as follows:

aBaCl_2+bAl_2S_3->cBaS+dAlCl_3

For each element, we can have a balance equation:

Ba: a=c

Cl: 2a=3d

Al: 2b=d

S: 3b=c

You can notice that if you set one of these factors it will chain you to the next factor. Let's set a=1

a=1

c=a=1

3d=2a<=>d=2/3

2b=d<=>b=(2/3)/2=1/3

Now the equation can be balanced:

BaCl_2+1/3Al_2S_3->BaS+2/3AlCl_3

However, many don't like the fractions because of the molecule concept. Since they have a common denuminator, multiply everything by 3 to get ride of the fractions:

3BaCl_2+Al_2S_3->3BaS+2AlCl_3