Question

How does the law of conservation of mass apply to this reaction C2H4 + O2 > 2H2O + 2CO2

Answer 1

It alwase equals the same amount of mass after the reaction

Answer 2

Answer: The total mass on the reactant side is equal to the total mass on the product side.

Explanation:

Law of conservation of mass 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 mass on the reactant side must be equal to the total mass on the product side.

The chemical equation for combustion of ethene follows:

$C_2H_4+3O_2\rightarrow 2H_2O+2CO_2$

On the reactant side:

Mass of ethene = $[(2\times 12)+(4\times 1)]=28g/mol$

Mass of oxygen gas = $3[(2\times 16)]=96g/mol$

Total mass on the reactant side = $(28+96)=124g/mol$

On the product side:

Mass of water = $2[(2\times 1)+16]=32g/mol$

Mass of carbon dioxide gas = $2[(1\times 12)+(2\times 16)]=88g/mol$

Total mass on the product side = $(32+88)=124g/mol$

As, total mass on the reactant side is equal to the total mass on the product side.

Hence, the above equation follows law of conservation of mass.