Chemical Thermodynamics MCQs for NEET — Chemistry Questions with Answers

For the reaction $CO_{(g)} + {1 ackslash 2} O_{2(g)} ightarrow CO_{2(g)}$, the enthalpy change (ΔH) is greater than the change in internal energy (ΔE) because the reaction involves a change in the number of moles of gas. At constant temperature and pressure, the enthalpy change includes the pressure-volume work done by the system, making ΔH larger than ΔE.

The change in enthalpy (ΔH) can be less than the change in internal energy (ΔE) if the number of moles of the products is less than the number of moles of the reactants. This is because ΔH = ΔE + PΔV, and if the volume decreases (fewer moles of gas), then PΔV is negative, making ΔH less than ΔE.

Enthalpy is an extensive property. Extensive properties depend on the amount of matter in a sample. Since enthalpy is proportional to the amount of substance, it is classified as an extensive property.

Hess's Law of Heat Summation states that the total enthalpy change of a reaction is the same, regardless of the number of steps the reaction is carried out in. Thus, it includes both the initial reactants and final products. This implies that the enthalpy change is dependent on the initial and final states of the reactants and products.

As dew formation is spontaneous process therefore entropy or
randomness of the universe will increase. As randomeness of the system has decreased but randomness of the surrounding will increase larger so that change is positive.

It I is because of the fact that for spontaneity, the value of OG = (OH – TOS) should be $ \lt 0 $ . If OS is – ve, the value of TOS shall have to be less than OH or the value of OS has to be less than that of x

Spontaneous adsorption of a gas on a solid surface is exothermic because it leads to a decrease in the entropy of the system. The gas molecules lose their freedom of movement when they get adsorbed onto the solid surface, leading to a decrease in entropy.

According to the third law of thermodynamics, at absolute zero (0 K), the entropy of a perfectly crystalline substance is zero. This is because a perfectly crystalline substance at absolute zero has only one possible microstate, leading to zero entropy.