Chemical equation and reaction full notes class 10 for free download.
Physical and chemical changes Chemical change - one or more new substances with new physical and chemical properties are formed. Example: F e ( s ) + C u S O 4 ( a q ) → F e S O 4 ( a q ) + C u ( s ) (Blue) (Green) Here, when copper sulphate reacts with iron, two new substances, i.e., ferrous sulphate and copper are formed. Physical change - change in colour or state occurs but no new substance is formed. Example: Water changes to steam on boiling but no new substance is formed(Even though steam and water look different when they are made to react with a piece of Na, they react the same way and give the exact same products). This involves only change in state (liquid to vapour). Observations that help determine a ch...