For each of the following reactions state the signs of ∆H (enthalpy) and ∆S (entropy): a) Fusion of ice. b) Sublimation of CO 2 c) Vaporization of aqueous water. d) Deposition of chlorine gas. e) Condensation of water vapor.

Okay, guys, let's look at practice question to were asked to find the signs of Delta H and Delta s. So here we know that fusion just means melting. And remember, if you're melting, you're going from solid toe liquid. And in this case, where breaking bonds And if you're breaking Bonds, we'd expect that both Delta H and Delta s to be positive for the next one. We have the sublimation off CO two now. Hope you guys remember what sublimation means. Sublimation just means we're going from solid to gas and again we're breaking bonds. So this means that both will be positive. And just remember that going from solid to liquid requires us to absorb energy in order to break these bonds to go into a liquid phase. But going from solid to gas is an even bigger jump. So you're gonna need to require it's gonna require you to absorb even mawr energy. So Mawr Energy is required to go from solid to gas than from going from solid to liquid. Next vaporization vaporization is just going from liquid two gas. So again, or breaking bonds. So both should be positive. Deposition is just the opposite of sublimation here we're depositing a solid. So we're going from gas to solid and because we're going from gas to solid word, forming new bonds so both should be negative. And then the last one condensation is the opposite Off vaporization, we're going from gas toe liquid. We're forming new bonds, so both will be negative. Hope you guys were able to get these questions correct. But again, it's all based on you knowing the definitions of these words. So it's kind of hard, because in the earlier one we had a chemical equation, which we could kind of see what to do here. You have to know the definition. Also, just realize that Delta s and Delta H will always be the same sign. It just happens to be when they're forming bonds or breaking bonds. They usually have the same type of sign. But this is not always the case. We're gonna learn that when it comes to spontaneity, Delta s and Delta H really aren't the best criteria toe look at the best way to determine if something is spontaneous or not is to really look at Delta G, which is called Gibbs Free Energy. We'll go more into Gibbs free energy later on, when we go deeper into this chapter. But for now, just remember the trends when it comes to figuring out the science for Delta H Delta S N Delta G and remember that they don't always agree in sign Delta H and Delta s aren't always the same exact sign. We'll see this the further into the chapter we go.

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1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

19. Chemical Thermodynamics

Entropy

General Chemistry

19. Chemical Thermodynamics

Entropy

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Multiple Choice

For each of the following reactions state the signs of ∆H (enthalpy) and ∆S (entropy):
a) Fusion of ice.
b) Sublimation of CO₂
c) Vaporization of aqueous water.
d) Deposition of chlorine gas.
e) Condensation of water vapor.

a) — b) — c) + d) — e) +

a) — b) — c) — d) — e) —

a) + b) + c) + d) — e) —

a) — b) — c) — d) + e) +

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Verified step by step guidance

Identify the type of process for each reaction: a) Fusion of ice is melting, b) Sublimation of CO2 is a solid turning into gas, c) Vaporization of aqueous water is liquid turning into gas, d) Deposition of chlorine gas is gas turning into solid, e) Condensation of water vapor is gas turning into liquid.

Understand the concept of enthalpy (∆H): For endothermic processes (absorbing heat), ∆H is positive. For exothermic processes (releasing heat), ∆H is negative.

Understand the concept of entropy (∆S): Entropy increases (positive ∆S) when disorder increases, such as when a substance changes from solid to liquid or liquid to gas. Entropy decreases (negative ∆S) when disorder decreases, such as when a substance changes from gas to liquid or liquid to solid.

Apply these concepts to each reaction: a) Fusion of ice involves solid to liquid, so ∆H is positive and ∆S is positive. b) Sublimation of CO2 involves solid to gas, so ∆H is positive and ∆S is positive. c) Vaporization of aqueous water involves liquid to gas, so ∆H is positive and ∆S is positive.

Continue applying these concepts: d) Deposition of chlorine gas involves gas to solid, so ∆H is negative and ∆S is negative. e) Condensation of water vapor involves gas to liquid, so ∆H is negative and ∆S is negative.