100 ml of hydrogen + 50 ml of oxygen = 100ml of water.....is this not voilating law of conservation of mass??

Question

Is the above question does voilate law of conservation of mass

Answer 1

Let's look at the chemical equation in question.

2H₂ + O₂ ==> 2H₂O

As can be seen from the BALANCED equation, it takes twice as much H₂ as it does O₂ to make water.  And the amount of water is equal to the amount of H2 and equal to half the amount of O2.  The "amounts" can be in mls or moles as long as both H₂ and O₂ are being measured at the same temperature and pressure.  So, this DOES NOT violate the law of conservation of mass.

 

Take 2 moles H₂ and 1 mole of O₂ to make 2 moles of H₂O

Mass of reactants = 2 x 2 = 4 g + 1 x 32 = 32 g = 36 g total mass of reactants

Mass of product = 2 x 18 = 36 g total mass of product

 

The same will be true with 100 ml H₂ and 50 ml O₂ to make 100 ml H₂O as long as they are at the same temperature and pressure.