Which of the following chemical equations proves that the law of conservation of mass is in effect? Question 2 options:

Mg2 + LiBr ---> LiMg + Br

2KCl + F2 ---> 2KF + Cl2

Na +O2 ---> Na2O

H20 ---> H2 + O2

2KCl + F₂   →     2KF + Cl₂

Explanation:

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

2KCl + F₂   →     2KF + Cl₂

In this equation mass of reactant and product is equal. There are 2 potassium 2 chlorine and fluorine atoms on both side of equation it means mass remain conserved.

All other options are incorrect because mass is not conserved.

Mg₂ + LiBr ---> LiMg + Br

In this equation mass of magnesium is more on reactant side.

Na +O₂ ---> Na₂O

In this equation there is more oxygen and less sodium on reactant side while there is more sodium and less oxygen on product side.

H₂O ---> H₂ + O₂

In this equation there is less oxygen on reactant side while more oxygen on product side.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.

2b2t

explanation:

2b2t