Answer sheets of meritorious students of class 12th’ 2012 M.P Board – All SubjectsFebruary 14, 2013
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NCERT Solutions for Class 9 Science Chapter 3: The chapter covers all the basics of Atoms and Molecules. The chapter is of significant importance since the primary understanding of atoms and molecules is necessary to understand its dependent and complex topics in Class X, XI, and XII. The topic is also important regarding career prospects in Chemistry and Biotechnology. Students are advised to thoroughly study this chapter and get all their basic doubts cleared.
Atoms and molecules chapter mainly talks about Law of Conservation of Mass, Law of Definite Proportions, Postulates of Dalton’s Atomic Theory, Atoms, Molecules and Ions and many more. Embibe delivers over 470 practice questions for all the sub-topics of chapter 3 Class 9 Science. Students must study all the in-text questions curated by Embibe to achieve good marks. Keep scrolling to access the NCERT solutions for Class 9 Science chapter 3.
Atoms and Molecules is one of the easiest concepts to understand. Students are advised to go through the concepts first so that they can solve the questions easily. Solving as many questions as possible is advisable to develop speed and accuracy in problem-solving. The more the questions are practised, the easier it becomes to answer the questions in the final exam.
Embibe offers solutions to all the questions in the Class 9 Science chapter 1 textbook, considering the latest syllabus. Students can solve the questions at Embibe for free. Along with the free NCERT solutions, students can also access NCERT 3D Videos, NCERT Exemplars, Embibe Explainers, etc., for free at Embibe.
Students can go through the list of topics of Class 9 Science chapter 1 as mentioned below:
|1||Laws of Chemical Combination|
|5||Writing Chemical Formulae|
|6||Molecular Mass and Mole Concept|
We have provided some of the important points to remember for NCERT Class 9 Science chapter 3 as mentioned below:
Ans: We know hydrogen and water mix ratio 1: 8.
For every 1g of hydrogen, it is 8g of oxygen. Therefore, for 3g of hydrogen, the quantity of oxygen = 3 x 8 = 24g. Hence, 24g of oxygen would be required for the complete reaction with 3g of hydrogen gas.
Ans: The postulate of Dalton’s Atomic theory, which is a result of the law of conservation of mass, is “Atoms can neither be created nor destroyed”.
Ans: The postulate of Dalton’s atomic theory that can explain the law of definite proportions is – the relative number and kinds of atoms are equal in given compounds.
Ans: The following are the formulae: (i) sodium oxide – Na2O, (ii) aluminium chloride – AlCl3, (iii) sodium sulphide – Na2S and (iv) magnesium hydroxide – Mg (OH)2.
Ans: The number of atoms present is as follows: (i) H2S molecule has 2 atoms of hydrogen and 1 atom of sulphur, hence 3 in totality and (ii) PO43- ion has 1 atom of phosphorus and 4 atoms of oxygen hence 5 atoms in totality.
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