title: Understanding Chemical Reactions
author:  M. C. Day 
description: Whereas this book was written primarily with the introductory chemistry course in mind, the authors feel that it will be of help both as a review for students taking an advanced inorganic chemistry course and as a review of basic chemistry for new graduate students.
zlib_text: Chemical Reactions
  and Equations
  1
  CHAPTER
  C
  onsider the following situations of daily life and think what happens
  when –
  �
  milk is left at room temperature during summers.
  �
  an iron tawa/pan/nail is left exposed to humid atmosphere.
  �
  grapes get fermented.
  �
  food is cooked.
  �
  food gets digested in our body.
  �
  we respire.
  In all the above situations, the nature and the identity of the initial
  substance have somewhat changed. We have already learnt about physical
  and chemical changes of matter in our previous classes. Whenever a chemical
  change occurs, we can say that a chemical reaction has taken place.
  You may perhaps be wondering as to what is actually meant by a
  chemical reaction. How do we come to know that a chemical reaction
  has taken place? Let us perform some activities to find the answer to
  these questions.
  Figure 1.1
  Burning of a magnesium ribbon in air and collection of magnesium
  oxide in a watch-glass
  Activity 1.1
  Activity 1.1
  Activity 1.1
  Activity 1.1
  Activity 1.1
  CAUTION: