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1800-102-2727This concept page deals with the physical and chemical changes. To better understand, consider an iron rod.
What happens when the iron rod is bent?
It undergoes a physical change. The iron rod which was linear before has lost its linearity.
Similarly, what happens when the iron rod gets rusted?
The iron atoms in the iron rod are oxidised to iron oxide. Therefore, it undergoes a chemical change.
In this concept page, we will get to know more about physical changes, chemical changes and their differences.
TABLE OF CONTENTS
A substance's structure and chemical makeup are both impacted by these modifications. Because the modifications it makes are reversible, the situation can return to how it was originally. When a substance undergoes modifications that do not influence its chemical bonds, a physical change takes place. It results in modifications to a substance's external appearance, including changes to shape, colour, and size. It is used to separate mixtures into the substance's constituents. These modifications are made through reactions that do not alter the chemical structure in any way. It is contrary to a chemical change, where the reactants combine to create new products. In order to separate mixtures into their respective components, physical modifications are used. It is employed to separate a chemical into more basic components. It also involves modifications to its specific physical characteristics, such as texture, toughness, and change.
Heating and cooling: A substance’s phase can be changed by either heating or cooling it. When a substance is heated, it changes its physical state from a solid to liquid or liquid to gas or solid to gas. When a substance is cooled, it changes its physical state from gas to liquid or liquid to solid, or gas to solid.
Magnetism: Materials that naturally exhibit ferromagnetism are magnetic. It is reversible.
Example: Melting of ice. A block of ice can turn into liquid water as the temperature changes, but the water can also turn back into ice on cooling.
Chemical changes usually happen when two or more substances combine and this combination results in a change in their chemical bonds. Chemical changes are permanent. They are unable to return to their former configuration after they have changed into a different form. Chemical changes are also referred to as chemical reactions. The rearrangement of the atoms that occurs during chemical changes typically results in the gain or loss of electrons. Exothermic and Endothermic reactions are thus two categories of chemical reactions. Exothermic chemical changes are those in which heat energy is released to create a new product. Heat and light are the two forms of energy that are released. An endothermic chemical change is another type of chemical change in which energy is required for a reaction to take place. There are numerous further types of chemical changes.
Organic Change - Organic change is the chemical change occurring in a compound containing carbon.
Biochemical Change - This change relates to chemical processes that take place throughout the function and development of biological things.
Example: Rusting of iron is a well-known example of chemical change. Iron forms ferric oxide when it is exposed to air and oxygen (Fe2O3). The iron acquires a reddish-brown hue as a result.
Physical Change |
Chemical Change |
Though the molecules rearrange, the composition remains the same |
The molecules rearrange themselves, and the composition completely changes. |
The modification is reversible. |
The transformation is irreversible. |
It only changes physical characteristics such as colour, size, and shape. |
Not only do the physical properties change, but so do the chemical bonds. |
It does not require a large amount of energy absorption. |
Energy is either absorbed or released in a chemical change. |
Physical changes do not need the absorption of energy. |
Chemical changes need a change in energy. |
There is no new substance formed. |
New substances are formed. |
Examples: Melting of ice, boiling of water, etc., |
Examples: Digestion of food, rusting or iron, etc,. |
Answer: D
Solution: Chemical and physical changes adhere to the law of mass conservation. As a result, mass remains constant. The properties given in other options can change in physical and chemical changes.
So, option D is the correct answer.
Answer: A
Solution:
Thus, the process given in option A is a physical change.
So, option A is the correct answer.
Answer: D
Solution:
Thus, the processes given in a), b) and c) are chemical changes whereas, the process given in d) is a physical change.
So, option D is the correct answer.
Answer: D
Solution:
Thus, the statements given in options A), B) and C) are true.
So, option D is the correct answer.
1. How do you distinguish between physical and chemical changes?
Answer: During a physical change, the appearance or form of matter changes, but the type of matter in the substance does not. A chemical change, on the other hand, produces at least one new substance with new properties.
2. Why is it important to understand the distinction between physical and chemical changes?
Answer: It is critical to distinguish between chemical and physical changes. There are several obvious changes, but there are some fundamental concepts to be aware of. Physical changes are typically changes in the physical state of something. Chemical changes occur on a molecular level when two or more molecules interact.
3. What are the three physical forces that can cause a change?
Answer: Physical changes can be caused by three major forces such as motion, temperature, and pressure. On the contrary, chemical changes can be caused by the combination of two or more substances in addition to motion, temperature and pressure.
4. Can physical and chemical changes happen simultaneously?
Answer: Yes, physical and chemical changes can happen simultaneously in some cases. The burning of a candle is one such example. The wax in the candle melts and becomes liquid. This implies that the change is physical in nature. At the same time, the carbon and hydrogen in the candle react with the oxygen in the air to form new products. This implies that a chemical change is taking place.
Related Topics
Metals and non-metals |
Difference between atom and molecule |
Difference between molecules and compounds |
Mixtures |
Difference between compounds and mixtures |
Non-metals |