Question

What coefficients would result in the below chemical equationbeing balanced? (The coefficients in the answers are written in thesame order as they would be placed into the chemical equation.)Chemical Equation:__Al(s) +_HCl(aq) --> ___AICI3(s) +H2(g)——--——

Answer 1

To balance the equation we must count the number of atoms of each element on each side of the reaction. The reaction will be balanced when the number of atoms of each element is the same on both sides of the reaction. Let's see how many atoms we have in the following table. I will update the table as we find the coefficients.

We will start by balancing the chlorine, there are 3 chlorines in the products and one in the reactants, we will place the coefficient 3 in the HCl molecule. I will update the table and I will count the atoms again.

Now we will balance the hydrogen. We see that there are three hydrogens in the reactants and two in the products, in order to balance it we must modify the coefficients of both molecules that contain hydrogen. We will look for a multiple of 3 and 2, we will put 6 hydrogens on each side of the reaction. So we must place the coefficient 6 in HCl and 3 in the H2 molecule. I will update the table.

When balancing the hydrogen we must balance the chlorine again, placing the coefficient 2 in the AlCl3 molecule, thus we will have 6 chlorines on each side of the reaction.

To finish we balance the Aluminum, and we place the coefficient 2 in the Al molecule. I will update the table.

Now, the equation is balanced. The order of the coefficients will be:

2, 6, 2, 3

2 Al(s) + 6 HCl(aq) --> 2 AICI3(s) + 3 H2(g)