Question

3. Why is respiration considered an exothermic reaction? b)

Why do copper vessel lose shine when exposed to air ​

Answer 1

Answer:

a. Carbolydrates present in food are broken down to form glucose. This glucose combines with oxygen in the cells of our body and provides energy. This reaction is known as respiration. hence,respiration is considered as an exothermic reaction.

b. A copper vessel reacts with oxygen present in air when exposed to it , they forms copper oxide which , in turn , is a black coating over the vessel and makes the vessel to lose its shine . The copper oxide which is formed is black in colour

Answer 2

Exothermic reactions release heat or energy.When we breath out,breath is warmer.This is happened for respiration reaction of our body. Carbolydrates present in food are broken down to form glucose.This glucose combines with oxygen in the cells of our body and provides energy.This reaction is known as respiration.hence,respiration is considered as an exothermic reaction.

when a copper vessel reacts with oxygen which is present in the air it forms a substance called copper oxide which makes the vessel lose its shine

hope i helped :)