Question

Which equation shows conservation of mass and energy for a reaction at 101.3 kpa and 298 k?

a.2h2(g) + o2(g) 2h2o(g) + 483.6 kj
b.2h2(g) + o2(g) 2h2o(l) + 285.8 kj
c.h2(g) + o2(g) h2o(g) + 483.6 kj
d.h2(g) + o2(g) h2o (l) + 285.8 kj?

Answer 1

C and D are not correctly balanced so it is not show conservation of energy also for B the energy value is not correct it is not show conservation of mass and energy so the correct answer is A:
2 H₂(g) + O₂(g) → 2 H₂O(g) +483.6 kJ

Answer 2

Answer is: a.2h2(g) + o2(g) 2h2o(g) + 483.6 kj.

Conservation of mass (mass is never lost or gained in chemical reactions), during chemical reaction no particles are created or destroyed, the atoms are rearranged from the reactants to the products.

The law of conservation of energy states that the total energy of an isolated system remains constant; energy can neither be created nor destroyed; it can only be transformed or transferred from one form to another.

Balanced chemical reaction: 2H₂ + O₂ → 2H₂O ΔH = 483.6 kJ.

There are four hydrogen atoms and two oxygen atoms on both side of balanced chemical reaction.