Question

Test the law of mass conservation on the reaction : CuSO4 + heat= CuO + SO3

Answer 1

According to law of mass conservation:- In a stoichiometrically balanced chemical equation ,

The total mass of reactants = Total mass of the products formed

or, sum of the masses of reactants = sum of the masses of products formed

The masses of different reactants and /or products are usually calculated by adding up the atomic masses of different atoms present in the concerned molecule ( in case of compounds ) ,or atoms (In case of elements). Now,

in the given reaction CuSO₄   + heat = CuO + SO₃

hence , molecular masses of reactant & products 159.61 79.55 80.06

thus . molecular mass of the reactant sum of molecular masses of products

159.61 79.55 + 80.06

= 159.61

Again , since in a stoichiometrically balanced chemical equation the masses of reactant= sum of the masses of products, as verfied above -

" Law of mass conservation holds good "

Molecular masses of -

CuSO₄ = 63.55 + 32.06 + (16.00 x 4)   

= 159.61

CuO = 63.55 + 16

=79.55

SO₃ = 32.06 + 48

= 80.06

Note - (1) Atomic masses in amu has been taken up from ' Table of atomic masses ' as-

Cu = 64.55 ; S = 32.06 ; O = 16.00

(2) Energy/ heat is considered as massless so far as the Law of conserrvation of masses is concerned.