Law of Conservation of Mass
Law of Conservation of Mass states that “Mass can neither be created nor can be destroyed in a chemical reaction” but it can be transformed from one form to another.
In other words, in an enclosed system whenever matter undergoes a chemical or physical change, the total mass of reacting matter (reactants or matter before the change) is exactly equal to the total mass of reaction products. As no products or reactants are allowed to exit the system in a closed system, there is no loss of the substance, and hence the mass is conserved.
For example, in automobiles, fuel is burned to create energy for vehicles to move forward and the fuel is converted into fumes such as carbon dioxide, carbon monoxide, or sulfur dioxide, etc. This law was first outlined by Mikhail Lomonosov in 1756 and then further refinements are proposed by Antoine Lavoisier in 1773 after a lot of experiments.
Example of Law of Conservation of Mass
For an example of conservation of mass, let’s consider the formation of a water molecule from oxygen and hydrogen molecules. Balance chemical Reaction of formation of water is:
2H2 + O2 → 2H2O
In the above example, 2 molecules of Hydrogen combine with 1 molecule of Oxygen to form 2 molecules of water.
- Mass of H is 1 unit and O is 16 units.
- Mass of 2 molecules of Hydrogen (2H2) is 4 units.
- Mass of 1 molecule of Oxygen (O2) is 32 units.
- Mass of 2 molecules of water (2H2O) is 36 units.
2H2 + O2 → 2H2O
4 unit 32 unit 36 unit
The total mass of the reactants equals the total mass of the products in this case. Furthermore, the number of hydrogen and oxygen atoms in the reactant and product sides are also equal.
Laws of Chemical Combination
Laws of Chemical Combination are one of the most fundamental building blocks of the subject of chemistry. As in our surrounding different matter reacts with each other and form various kind of different substances. Laws of Chemical Combination are the collection of laws that explains how these substances combine together to form anything at all. When matter reacts with another matter, a chemical reaction happens which changes the form, properties, or characteristics of the matter drastically. This interaction of matter with each other is governed by the Laws of Chemical Combination.