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The NCERT Solutions for Class 9 Science are provided in this article. Some of the important topics in Chapter 3 Atoms and Molecules include:
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NCERT Solutions for Class 9 Science Chapter 3
Class 9 Science Chapter 3 Atoms and Molecules – Important Topics
Atom is the smallest constituent unit of matter that possess the properties of the chemical element. Atoms don’t exist independently, instead, they form ions and molecules which further combine in large numbers to form matter that we see, feel and touch.
Dalton’s Atomic Theory
Dalton’s Atomic Theory hypothesized and further claimed that the law of conservation of mass and the law of definite proportions could possibly de elaborated by using the idea of atoms. According to him, all substances are indestructible building units.
| Example: What are two postulates of Dalton’s Atomic Theory? Solution: The two postulates of Dalton’s Atomic Theory are:
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Atomic Mass
The complete mass of one atom of a distinct element can be otherwise called as its atomic mass. The unit it has is known as unified atomic mass unit, that is represented by the letter ‘u.’
| Example: Calculate the atomic mass of an oxygen isotope that has 9 neutrons. Solution: To calculate the atomic mass of an oxygen isotope, we need to know the number of protons and neutrons it has. |
Mole Concept
Mole concept can be defined as the atomic mass of a mole which is usually measured in grams. Ideally, the gram atomic mass of an element is otherwise referred to as a mole.
| Example: What is the formula of Mole Concept? Solution: The number of units responsible to compose mole can be evaluated by 6.022 ×10²³. The fundamental constant is called the Avogadro's number (NA) or Avogadro constant. It can be represented using an explicit unit termed per mole. Thus, to calculate Mole Concept, |
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| Important Science Study Guides | ||
|---|---|---|
| Physics Constants | Named Reactions | Difference between in chemistry |
| Difference between in biology | Difference between in physics | Periodic Table |
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