A common balance is used for measuring

Mass

Explanation:

A common balance, also known as a beam balance, is an instrument designed to measure the mass of an object. It operates on the principle of comparing the unknown mass to a known standard mass. When the masses on both sides of the balance are equal, the beam achieves equilibrium, indicating the mass of the object being measured.

It's important to distinguish between mass and weight.

• Mass: A measure of the amount of matter in an object, typically measured in kilograms (kg) or grams (g). Mass is a scalar quantity and remains constant regardless of location.
• Weight: The force exerted on an object due to gravity, calculated as the product of mass and gravitational acceleration. Weight is a vector quantity and can vary depending on the gravitational field strength.

Since a common balance measures mass by comparing it to known masses, it provides consistent measurements irrespective of local gravitational variations. This characteristic makes it a reliable tool for determining mass, not weight.

Note: While the term weight is often colloquially used to refer to mass, in scientific contexts, it's crucial to differentiate between the two. A common balance specifically measures mass.

Additionally, it's worth noting that thermodynamics is not concerned about the rate at which a reaction proceeds; instead, it focuses on the energy changes and feasibility of chemical reactions.