Consider the transformations a water sample undergoes without external pressure variation (a) Transformations 2 and 4 are endothermic.
(b) Transformations 1 and 2 are exothermic.
(c) The amount of energy absorbed in 3 is equal to the amount released in 1.
(d) The amount of energy released in 2 is equal to the amount released in 4.
(e) The change of physical state does not involve heat energy.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

a pan containing water is placed in a positio n where it is exposed to a 10 mile per hour wind. the pan contains a uniform depth of 1.27 cm of water, is quite wide, and has a length of 2.44 m in the wind direction. the water in the pan is at a constant temperature of 15.5 °c.