Question

state difference between exothermic and endothermic reactions and justify your answer

Answer 1

Explanation:

'Thermic' refers to 'heat ' while 'endo' refers to 'inside'
and 'exo' refers to 'outside ' or simply 'exit'

Hence,

An endothermic reaction is one during which energy is absorbed from the surrounding (for e.g: from thermometer, cup, beaker, solutions, etc...). The latter become colder.
an example is : photosynthesis (chlorophyll is used to react carbon dioxide + water +energy to make glucose and oxygen)

An exothermic reaction is one during which energy is liberated to the surrounding (for e.g : thermometer, beakers, etc...) causing the reaction mixture to become hotter.
an example is: combustion (burning)

another difference is that:
for endothermic reaction : the ΔH (enthalpy of system) is always positive i.e ΔH = +ve, meaning that the energy of the products is greater (>) than the energy of the reactants

while

for exothermic reactions , the ΔH is always negative
i.e, ΔH = −ve
in other words, the energy of reactants >energy of products

Answer 2

in exothermic reaction heat is released such as respiration
in endo thermic reaction heat is absorbed such as u can say melting of ice to form water in which heat is needed