Question

Avogadro s law finds application in the determination of (1) Atomicity of gases (2) Molecular weight of gases (3) Molecular formula of certain gaseous compounds (4) All the above

Short answer

(4) All the above

Step-by-step solution

Understanding Avogadro's Law

Avogadro's Law states that equal volumes of all gases, at the same temperature and pressure, have the same number of molecules. This principle helps in understanding the behavior of gases.

Application to Atomicity of Gases

Avogadro's Law helps in determining the atomicity of gases by comparing the volumes of gases under similar conditions and relating them to the number of molecules.

Application to Molecular Weight of Gases

The law also aids in determining the molecular weight of gases. By knowing the volume and the amount of gas (in moles), the molecular weight can be calculated using the formula: \(M = \frac{dRT}{P}\), where \(M\) is the molecular weight, \(d\) is density, \(R\) is the gas constant, \(T\) is the temperature, and \(P\) is the pressure.

Application to Molecular Formula of Gaseous Compounds

Avogadro's Law is used to determine the molecular formula of certain gaseous compounds by comparing the volumes and using the concept of moles to understand the ratio of atoms in a compound.

Conclusion

Since Avogadro's Law applies to various aspects such as atomicity, molecular weight, and molecular formula, it is evident that the law has multiple applications.

Key concepts

Atomicity of gases

Avogadro's Law plays a crucial role in understanding the atomicity of gases. Atomicity refers to the number of atoms in a molecule of a gas. This becomes more interesting when you consider gases like hydrogen \(H_2\), oxygen \(O_2\), and nitrogen \(N_2\). Thanks to Avogadro's Law, we know that equal volumes of these gases, under the same conditions of temperature and pressure, will contain the same number of molecules. By comparing volumes and using Avogadro's principle, we can deduce the atomicity of a gas.
For instance:

• A single molecule of hydrogen consists of 2 atoms of hydrogen, so its atomicity is 2.
• Similarly, a molecule of oxygen also consists of 2 atoms, making its atomicity 2.

This insight facilitates the understanding of more complex gases and helps in predicting their chemical behavior and reactions.

Molecular weight determination

Avogadro's Law is not only foundational for understanding atomicity but also crucial for determining the molecular weight of gases. The molecular weight, also known as the molar mass, can be calculated using the relationship given by Avogadro's Law:

\[M = \frac{dRT}{P}\text{, where }M\text{ is the molecular weight, }d\text{ is density, }R\text{ is the gas constant, }T\text{ is temperature, and }P\text{ is pressure}.\text{.}\]

By rearranging this formula, the molecular weight of a gas can be determined if the other variables are known. This application is particularly useful in chemistry and other sciences where precise measurements of gas properties are needed.

Molecular formula determination

Lastly, Avogadro's Law helps us determine the molecular formula of certain gaseous compounds. The molecular formula reveals the exact number of atoms of each element in a single molecule of a compound. To determine this, we leverage the concept of moles and ratios. For example, if we know the volume of gases involved in a reaction and their respective mole ratios, we can infer the molecular formula of the resulting compound.
For instance:

• If we react hydrogen \(H_2\) with oxygen \(O_2\) to form water \(H_2O\), we can use the mole ratio (2:1:2) to determine the molecular formula \(H_2O\).

Therefore, by using Avogadro's Law and understanding mole concepts, we can accurately determine the molecular formula of various gaseous compounds.