Question

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

Hydrogen and chlorine need to be balanced. There is an equal amount of aluminum on each side.


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


The law of conservation of mass has already been applied. There is an equal number of each element on both sides of the equation.


The equation needs to be balanced. There are fewer hydrogen atoms in the equation than aluminum or chlorine.

Answer 1

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

Step-by-step 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.