NEET · Chemistry · Chemical Thermodynamics doubts

What does “Enthalpy (H)” actually mean in Chemical Thermodynamics, and why does it matter for NEET?

the heat content at constant pressure; ΔH is negative for exothermic and positive for endothermic reactions.

I keep getting “Enthalpy (H)” questions wrong in Chemical Thermodynamics. What's the trap?

getting the sign of ΔH the wrong way round.

What does “Entropy (S)” actually mean in Chemical Thermodynamics, and why does it matter for NEET?

a measure of disorder or the number of ways energy can be arranged.

I keep getting “Entropy (S)” questions wrong in Chemical Thermodynamics. What's the trap?

thinking entropy always increases for the system alone.

What does “Gibbs free energy” actually mean in Chemical Thermodynamics, and why does it matter for NEET?

ΔG = ΔH − TΔS decides spontaneity — negative ΔG means the process is spontaneous.

I keep getting “Gibbs free energy” questions wrong in Chemical Thermodynamics. What's the trap?

judging spontaneity from ΔH alone.

What does “Hess's law” actually mean in Chemical Thermodynamics, and why does it matter for NEET?

the total enthalpy change is the same no matter the route taken.

I keep getting “Hess's law” questions wrong in Chemical Thermodynamics. What's the trap?

thinking ΔH depends on the reaction path.

What is the difference between enthalpy and entropy?

Enthalpy is about heat content/energy; entropy is about disorder — spontaneity balances the two through ΔG.

What is the difference between exothermic reaction and endothermic reaction?

Exothermic releases heat (ΔH<0, surroundings warm); endothermic absorbs heat (ΔH>0, surroundings cool).

What is the difference between system and surroundings?

The system is the reaction you study; the surroundings are everything else that can exchange heat/work with it.

When do I use ΔG = ΔH − TΔS in Chemical Thermodynamics, and what does it mean?

Gibbs free energy change deciding spontaneity.