Question

pls give answer bit wise. How can you say these are chemical changes? Give one reason for your answer? 1-burning of candle 2-milk sours in hot and humid weather 3-decomposition of water into hydrogen and oxygen 4-rusting of iron 5-a frog breathes heavily

Answer 1

1. because after melting it can't be again turned into a candle
2. After it sour it turns to cheese or paneer which can't be turned into milk
3. i don't know
4.iron after rusting sometime change into very small particles which after heating also don't change into iron.
5.i don't know

Answer 2

1) It is not chemical change
2) We can not get milk back after souring
3) Chemical property is changed
4) We can not get pure iron back after rusting and new product rust is form
5) It is not chemical change