Question

Cellular respiration is a biological process in which glucose is broken down to form energy in the form of ATP. The reactants have a starting energy of 3564 kilojoules of energy, and the products have a resulting 2878 kilojoules of energy.

Which best describes cellular respiration?
It is an exothermic reaction because energy is lost.
It is an exothermic reaction because energy is gained.
It is an endothermic reaction because energy is lost.
It is an endothermic reaction because energy is gained.

Answer 1

It is an endothermic reaction because energy is lost.

Answer 2

Answer: The correct answer is- It is an exothermic reaction because energy is lost.

As per the question, the starting energy of reactants for cellular respiration is 3564 kilojoules and energy of products is 2878 kilojoules.

We can find out whether a reaction is exothermic or endothermic by calculating ΔH that is energy change or enthalpy change of a reaction.

A negative value of ΔH represents exothermic reaction ( energy is lost) whereas a positive value represents endothermic reaction ( energy is consumed).

ΔH =
`H_(final)-H_(initial)`

ΔH = 2878- 3564

ΔH = -686 kilojoules

As the value of ΔH is negative, this represents energy is lost in this reaction and therefore, it is an exothermic process.