Question

How does the law of conservation of mass apply to this reaction: Al + 3HCl → H2 + AlCl3 ?

Answer 1

Answer:

Only the hydrogen needs to be balanced. There are equal numbers of aluminum and chlorine.

Explanation:

I took the K12 test, listened to some other idiot and got it wrong, so this is the correct one.

Hope this helps!

Answer 2

Answer: Only the hydrogen needs to be balanced. There are equal numbers of aluminum and chlorine.

Explanation:

A balanced chemical equation always follow law of conservation of mass.

This law states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form. This also means that total number of individual atoms on reactant side must be equal to the total number of individual atoms on the product side.

For the given chemical equation, the balanced reaction follows:

$2Al+6HCl\rightarrow 3H_2+2AlCl_3$

On reactant side:

Number of aluminium atoms = 2

Number of hydrogen atoms = 6

Number of chlorine atoms = 6

On product side:

Number of aluminium atoms = 2

Number of hydrogen atoms = 6

Number of chlorine atoms = 6

Hence, only the hydrogen needs to be balanced. There are equal numbers of aluminum and chlorine.