An iron rod is heated till it becomes red-hot.

Is heating of the iron rod a chemical change? Select the correct response with explanation.

Ramesh describes how roti is made in his house in 5 steps. Here are the 5 steps:

i). Wheat grains are ground to make flour.

ii). Flour is mixed with water to make soft dough.

iii). Small balls of dough are flattened out with a rolling pin.

iv). The flat round dough is cooked on a pan.

v). The crisp roti is coated with a layer of butter.

In which of the above steps does a physical change take place and in which one does a chemical change take place?