Fill in the blanks in the following stat | Class 7 Science Chapter Physical and Chemical Changes, Physical and Chemical Changes NCERT Solutions

Welcome to the NCERT Solutions for Class 7 Science - Chapter Physical and Chemical Changes. This page offers a step-by-step solution to the specific question from Exercise 1, Question 3: . With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.

Question 3:

Fill in the blanks in the following statements:

(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________.
(b) The chemical name of baking soda is _________.
(c) Two methods by which rusting of iron can be prevented are _________ and _________.
(d) Changes in which only _________ properties of a substance change re called physical changes.
(e) Changes in which new substances are formed are called _________ changes.

Answer:

(a) Calcium carbonate (CaCO3)
CO2 that is Carbon dioxide reacts with Ca(OH)2 (Calcium hydroxide) that is lime water, to form a white precipitate of CaCO3 (Calcium carbonate).

(b) Sodium hydrogen carbonate
The chemical name of baking soda is (NaHCO3) Sodium hydrogen carbonate (Sodium bicarbonate) .Sodium bicarbonate comes with sodium, acid and hydrogen. Sodium carbonate is diprotic and a strong base compound.

(c) Painting and galvanization                                                                                                                                                                                                      Metals which cannot wear easily are melted into their molten form and are used to cover metals which rust easily. The surface of iron or metal are coated with paint or grease. Galvanization is the process of applying a protective layer of zinc on a metal. It is a very common method of preventing the rusting of iron.

(d) Physical
The change in which physical properties of the substance or a material change, this is called physical change. In physical changes, no new substances are formed.

(e) Chemical
The changes in which cannot be seen by naked eyes are called chemical changes. The chemical changes cannot be reversed.


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Physical and Chemical Changes.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

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Welcome to the NCERT Solutions for Class 7 Science - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 3: Fill in the blanks in the following statements: (a) When carbon dioxide is passed through lime wa....