There are five (easy) ways to detect a reaction:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.

Signs of a physical change include:

1. Expected color change.
2. Change in size or shape.
3. Change in state of matter.
4. Reversible.
5. No new substance formed!

1. Color Change.
2. Precipitate Formation (solid formation falling out of solution)
3. Gas Formation (bubbles and odor)
4. Temperature Change.
5. pH Change.

Seven Things That Indicate a Chemical Change Is Occurring

• Gas Bubbles Appear. Gas bubbles appear after a chemical reaction has occurred and the mixture becomes saturated with gas.
• Formation of a Precipitate.
• Color Change.
• Temperature Change.
• Production of Light.
• Volume Change.
• Change in Smell or Taste.

The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.

Examples of physical change include changes in the size or shape of matter. Changes of state—for example, from solid to liquid or from liquid to gas—are also physical changes. Some of the processes that cause physical changes include cutting, bending, dissolving, freezing, boiling, and melting.

Volume, mass, length, density, pressure, viscosity, and hardness are a few more physical properties. Chemical properties are those that get observed or measured when the substance undergoes a chemical change.

Both: They both invlove changes in the state of matter. They both have energy changes. There are new things made either way, no matter if the chemical composition is changed or not.

Explanation: In physical changes the appearance of substances is altered but not their nature, that is, the substances remain the same. In chemical changes a substance is transformed into new substances with different properties. Therefore the correct option is B.

Physical absorption — A non-reactive process e.g. when oxygen present in air dissolves in water. The process depends on the liquid and the gas, and on physical properties like solubility, temperature and pressure. Chemical absorption — A chemical reaction takes place when the atoms or molecules are absorbed.

The adsorption is known as van der Waals adsorption and the force is called van der Waals force. Since van der Waals force exists between any two molecules, physical adsorption can occur on any solid surface. The adsorbed substance is also easier to desorb, so the physical adsorption is reversible to a certain extent.

There are 2 types of absorption processes: physical absorption and chemical absorption, depending on whether there is any chemical reaction between the solute and the solvent (absorbent).

Physical adsorption, or physisorption, is a type of adsorption that occurs for most particles in contact with a solid or liquid surface. Condensation of water molecules sticking to a drinking glass is an example. As a result, fewer water molecules (which are not drawn to scale) can stick to the top part of the glass.

Common examples of adsorbents are clay, silica gel, colloids, metals etc. Adsorption is a surface phenomenon. The process of removal of adsorbent from the surface of adsorbate is known as desorption.

Physisorption, also called physical adsorption, is a process in which the electronic structure of the atom or molecule is barely perturbed upon adsorption.

Chemical Adsorption: It is also known as chemisorption. It occurs due to the strong chemical forces of bonding between adsorbate and adsorbent. From the examples given in the question, the Haber process and hydrogenation of vanaspati ghee are the examples of chemisorption.

Adsorption is present in many natural, physical, biological and chemical systems and is widely used in industrial applications such as heterogeneous catalysts, activated charcoal, capturing and using waste heat to provide cold water for air conditioning and other process requirements (adsorption chillers), synthetic …

Adsorption can be either physical or chemical, depending on the forces/interactions of adsorbate and adsorbent. Yet there is a chemical reaction occurring (i.e., if the mode of adsorption is chemisoprtion). For example, during ligand exchange processes.

Chemical adsorption, also known as chemisorption, on solid materials is achieved by substantial sharing of electrons between the surface of adsorbent and adsorbate to create a covalent or ionic bond. Thus, chemical adsorption may not be fully reversible, and could require high energy for regeneration.

Explanation: Activated complex formed during adsorption possess lower energy level in chemisorption as it is more exothermic.

Physical adsorption is reversible in nature (due to presence of weak van der waals forces) and chemical adsorption is irreversible in nature (due to presence of strong chemical bonds).

The reactive absorption of carbon dioxide by an aqueous solution of sodium hydroxide (NaOH) is also irreversible and there not as economically acceptable as the reversible reactive absorption of carbon dioxide by ethanolamine solutions.

Absorption is defined as the process when one thing becomes part of another thing, or the process of something soaking, either literally or figuratively. An example of absorption is soaking up spilled milk with a paper towel. A paper towel takes up water, and water takes up carbon dioxide, by absorption.

The process is reversible, i.e., desorption of the gas occurs by increasing the temperature or decreasing the pressure.

The second law of thermodynamics can be used to determine whether a process is reversible or not. Intuitively, a process is reversible if there is no dissipation. For example, Joule expansion is irreversible because initially the system is not uniform. All complex natural processes are irreversible.

A process is said to be irreversible if after the process has been completed in the forward and reverse orders, the system fails to return into the initial state. It is a matter of general experience that all natural spontaneous processes are irreversible, and no natural reversible processes exist.

incapable of being reversed