State the law of constant proportion and give one example?
Ans-A chemical compound is always found to be made up of the same elements combined together in fixed proportion by mass.
For ex-CaCO3----->CaO+CO2^
The law of constant proportion, also known as the law of definite proportions, states that a chemical compound is always composed of the same elements in the same fixed proportions by mass. This means that regardless of the amount or source of a compound, the ratio of the elements remains constant.
For example, let's consider calcium carbonate (CaCO3), which is commonly found in limestone. According to the law of constant proportion, calcium carbonate will always contain one calcium atom (Ca), one carbon atom (C), and three oxygen atoms (O) in a fixed proportion by mass.
When calcium carbonate is heated, it undergoes a chemical reaction and decomposes into calcium oxide (CaO) and carbon dioxide (CO2). Even in this reaction, the proportions of the elements remain constant. For every unit of calcium carbonate decomposed, it will always yield one unit of calcium oxide and one unit of carbon dioxide.
This principle holds true for all chemical compounds, as long as they are pure and not contaminated by impurities. The law of constant proportion helps us understand the predictable nature of chemical reactions and aids in the analysis and synthesis of compounds in chemistry.