Question

how can you say these are chemical change? 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 breather heavily​

Answer 1

Answer:

ok i tell that chemical change is possible.

let us conclude that from the following examples

1st burning of candle

When you light the candle, the wax present near the wick will melt. Wick absorbs the liquid wax. The liquid wax vaporizes due the heat produced by the flame. This wax vapor near to flame burns and gives new substances like Carbon Dioxide, Carbon soot, water vapours, heat and light.

2nd Milk sours in hot and humid weather

When milk turns sour for example in a warm room it is a chemical change. If it was a physical change you would be able to undo the souring of milk.

4th rusting of iron

when metal oxidises it starts to rust it and it cannot be brought back to its original form of clean and shining metal.

5th frog breathing heavily

In respiration the glucose molecules is oxidised to form carbon dioxide and water along with release of energy . since, in this new products are formed so it is a chemical change in this respect the frog breathing heavily is a chemical change

Answer 2

Answer:

The liquid wax vaporizes due the heat produced by the flame. This wax vapor near to flame burns and gives new substances like Carbon Dioxide, Carbon soot, water vapours, heat and light. When milk turns sour for example in a warm room it is a chemical change.

Explanation:

hope this us helpful to you....