1. Intro to General Chemistry

2. Atoms & Elements

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Spontaneous Process

Free Energy

&#916;Ssurroundings is positive when the system absorbs heat from the surroundings.

&#916;Ssurroundings will decrease as a result of an exothermic process.

&#916;Ssurroundings is always positive when &#916;Suniv is positive.

In order for the entropy of the universe to increase, the signs of the two changes will not be the same.

&#916;Ssurroundings is independent of the heat released or absorbed by the system.

&#916;Ssurroundings is always positive when &#916;Ssystem is negative for a spontaneous process.

Correct application of the second law of thermodynamics.

At constant pressure, qsys can be used to quantify the change in entropy of the system.

Which of the following is a true statement about &#916;Ssurroundings?

Indicate whether each statement is true or false.
(a) Unlike enthalpy, where we can only ever know changes in H, we can know absolute values of S.
(b) If you heat a gas such as CO2, you will increase its degrees of translational, rotational and vibrational motions.
(c) CO21g2 and Ar(g) have nearly the same molar mass. At a given temperature, they will have the same number of microstates.

When K > 1, &#916;G is negative, under standard conditions (when Q = 1) the reaction is spontaneous in the reverse direction.

K > 1, &#916;G is negative indicates a favorable forward reaction.

When K < 1, &#916;G is positive, under standard conditions (when Q = 1) the reaction is spontaneous in the forward direction.

K < 1, &#916;G is positive indicates a favorable reverse reaction.

When K < 1, &#916;G is negative, under standard conditions (when Q = 1) the reaction is spontaneous in the reverse direction.

K < 1, &#916;G is positive indicates a favorable forward reaction.

When K = 1, &#916;G is zero, and the reaction is never spontaneous.

When K = 1, &#916;G is zero, and the reaction is at equilibrium.

Review the equation that relates K and &#916;G

Which of the following is a true statement about the relationship between &#916;G and K?

Which of the following statements is/are true?

a) The rusting of iron by oxygen is a non-spontaneous reaction.

b) The addition of a catalyst to a reaction increases spontaneity.

c) The movement of heat from a cold object to a hot object is a non-spontaneous reaction.

d) The diffusion of perfume molecules from one side of a room to the other is a non-spontaneous reaction.

e) None of the above.&#160;

Chemical Thermodynamics 4.1 - Spontaneous Processes

The standard formation reaction involves the formation of one mole of the product, MgO.

The standard entropies of formation of magnesium and oxygen gas are not zero.

Recall that the summation equation is products minus reactants.

The equation for the reaction must be balanced and the summation equation is products minus reactants.

By definition, a formation reaction is a reaction in which one mole of product is formed from the elements in their natural states. S&#176; values can be found in tables in your textbook; &#916;S&#176;rxn = &#931;npS&#176;(products) &#x2212; &#931;npS&#176;(reactants)

Calculate &#916;S&#176;rxn (J/K) for the formation reaction of the salt MgO (s).

(a) What is the difference between a state and a microstate of a system?

Would each of the following changes increase, decrease, or have no effect on the number of microstates available to a system: (b) decrease in volume

Make a rough, qualitative plot of the standard molar entropy versus temperature for methane from 0 K to 298 K. Incorporate the following data into your plot: mp = -182 °C; bp = -164 °C; °S = 186.2 J/(K*mol) at 25 °C.

Calculate ΔS
surr at the indicated temperature for each reaction.
d. ΔHrxn ° = +114 kJ; 77 K

Which of these processes are nonspontaneous? Are the 
nonspontaneous processes impossible? 
a. a bike going up a hill 
b. a meteor falling to Earth 
c. obtaining hydrogen gas from liquid water 
d. a ball rolling down a hill

Indicate whether each statement is true or false.
(a) A reaction that is spontaneous in one direction will be nonspontaneous in the reverse direction under the same reaction conditions.
(b) All spontaneous processes are fast.
(c) Most spontaneous processes are reversible.
(d) An isothermal process is one in which the system loses no heat.
(e) The maximum amount of work can be accomplished by an irreversible process rather than a reversible one.

Consider the distribution of ideal gas molecules among three bulbs (A, B, and C) of equal volume. For each of the follow-ing states, determine the number of ways (W) that the state can be achieved, and use Boltzmann's equation to calculate the entropy of the state. 
(a) 2 molecules in bulb A
(b) 2 molecules randomly distributed among bulbs A, B, and C

The normal boiling point of Br21l2 is 58.8 °C, and its molar enthalpy of vaporization is ΔHvap = 29.6 kJ>mol.
(b) Calculate the value of ΔS when 1.00 mol of Br21l2 is vaporized at 58.8 °C.

Trouton's rule states that for many liquids at their normal boiling points, the standard molar entropy of vaporization is about 88 J>mol@K. (a) Estimate the normal boiling point of bromine, Br2, by determining ΔH°vap for Br2 using data from Appendix C. Assume that ΔH°vap remains constant with temperature and that Trouton's rule holds. (b) Look up the normal boiling point of Br2 in a chemistry handbook or at the WebElements website (www.webelements.com) and compare it to your calculation. What are the possible sources of error, or incorrect assumptions, in the calculation?

For the vaporization of benzene, ∆Hvap = 30.7 kJ/mol and ∆Svap = 87.0 J/(K*mol). Does benzene boil at 70 °C and 1 atm pressure? Calculate the normal boiling point of benzene.

The second law of thermodynamics states that for any spontaneous process the entropy of the universe must increase (&#916;Suniv > 0).

&#916;Ssurroundings is negligible.

&#916;Ssurroundings must also be positive.

Nothing; only &#916;Suniverse can tell about the overall spontaneity of a process.

Correct in accordance with the second law of thermodynamics.

&#916;Suniv = &#916;Ssystem + &#916;Ssurroundings

A positive &#916;Ssystem indicates what about the overall spontaneity of a process?

Trouton's rule says that the ratio of the molar heat of vapor-ization of a liquid to its normal boiling point (in kelvin) is approximately the same for all liquids: ∆Hvap/Tbp ≈ 88 J/(K*mol) 
(b) Explain why liquids tend to have the same value of ∆Hvap/Tbp.

Naphthalene, better known as 'mothballs,' has bp = 218 °C 
and ΔHvap = 43.3 k# J>mol. What is the entropy of vaporiza 
tion, ΔSvap in J>1K mol2 for naphthalene?

Which of these processes is spontaneous? 
a. the combustion of natural gas 
b. the extraction of iron metal from iron ore 
c. a hot drink cooling to room temperature 
d. drawing heat energy from the ocean's surface to power a ship

Use the values of &#916;H and &#916;S to determine the temperature when &#916;G = 0.

Correct temperature based on &#916;H and &#916;S.

This reaction is spontaneous at all temperatures.

The reaction is nonspontaneous at some temperatures.

This reaction is nonspontaneous at all temperatures.

The reaction is spontaneous at some temperatures.

The crossover temperature can be determined when &#916;G = 0.

At what temperature does the following reaction become nonspontaneous? 2 NO (g) + O2 (g) &#8594; 2 NO2 (g)

The accompanying diagram shows how entropy varies with temperature for a substance that is a gas at the highest temperature shown. 
 
(c) If this substance is a perfect crystal at T = 0 K, what is the value of S at this temperature?<img class="fr-dib" src="https://lightcat-files.s3.amazonaws.com/problem_images/dd26be0a7075c95b-1677068195544.jpg" style="width: 300px;">

The element gallium (Ga) freezes at 29.8 °C, and its molar enthalpy of fusion is ΔHfus = 5.59 kJ>mol. (b) Calculate the value of ΔS when 60.0 g of Ga(l) solidifies at 29.8 °C.

Calculate the change in entropy that occurs in the system when
1.00 mole of isopropyl alcohol (C3H8O) melts at its melting
point (-89.5 °C). See Table 11.9 for heats of fusion.

18.1 The Laws of Thermodynamics | General Chemistry

Spontaneous Processes

A reaction that requires no outside energy source is classified as a natural process and is spontaneous.&#160;

Trouton's rule says that the ratio of the molar heat of vapor-ization of a liquid to its normal boiling point (in kelvin) is approximately the same for all liquids: ∆Hvap/Tbp ≈ 88 J/(K*mol) 
(c) Which of the liquids in the table deviate(s) from Trouton's rule? Explain.

(c) In a particular spontaneous process, the number of microstates available to the system decreases. What can you conclude about the sign of ΔSsurr?

The gas state is less ordered than the solid state.

the dissolving of solid NaCl in water to make an aqueous solution

The solid solute is highly ordered compared to the aqueous solute.

the decomposition of liquid water into hydrogen gas and oxygen gas

This reaction involves the formation of two moles of gaseous product per one mole of liquid reactant.

the formation of ice from water at &#8722;25&#x2103;

the decomposition of carbon dioxide gas into carbon monoxide gas and oxygen gas

This reaction involves the formation of two moles of product per one mole of reactant.

A negative &#916;S is associated with a process that becomes more ordered (less random).

Which of the following would have a negative &#916;S?

Calculate the change in entropy that occurs in the system when
1.00 mole of diethyl ether (C4H10O) condenses from a gas to a
liquid at its normal boiling point (34.6 °C). See Table 11.7 for
heats of vaporization.

(b) As a system goes from state A to state B, its entropy decreases. What can you say about the number of microstates corresponding to each state?

positive &#916;S and positive &#916;H

This combination could produce either a positive value or a negative value of &#916;G depending on the temperature and the magnitudes of &#916;S and &#916;H.

negative &#916;S and positive &#916;H

This combination would produce a positive value of &#916;G at all temperatures.

positive &#916;S and negative &#916;H

Correct the value of &#916;G will always be negative with this combination.

negative &#916;S and negative &#916;H

A negative &#916;G indicates a spontaneous reaction; &#916;G = &#916;H &#x2212; T&#916;S

A process is always spontaneous under which conditions?

Which of the following processes are spontaneous and which are nonspontaneous: (d) lightning

There is more than one spontaneous process listed.

The decomposition of water requires an input of energy.

Correct, the decomposition of water requires an input of energy.

 A spontaneous process is a process that occurs without ongoing outside intervention. 

Which of the following is (are) spontaneous processes?(i)	a ball rolling down a hill (ii)	a car rusting (iii)	the decomposition of water into H2 gas and O2 gas

Consider the vaporization of liquid water to steam at a pressure of 1 atm. (c) In what temperature range is it a nonspontaneous process?

Chloroform has ΔHvaporization = 29.2 kJ>mol and boils at 61.2 °C. What is the value of ΔSvaporization for chloroform?

Thermodynamics | Spontaneous Process & Entropy.

Spontaneous Reaction

Entropy: Embrace the Chaos! Crash Course Chemistry #20

Which of the following processes are spontaneous and which are nonspontaneous: (e) formation of CH4 and O2 molecules from CO2 and H2O at room temperature and 1 atm of pressure?

(b) Based on your general chemical knowledge, predict which of these reactions will have K 7 1.
(i) 2 Mg1s2 + O21g2Δ2 MgO1s2
(ii) 2 KI1s2Δ2 K1g2 + I21g2
(iii) Na21g2Δ2 Na1g2
(iv) 2 V2O51s2Δ4 V1s2 + 5 O21g2

Understanding Spontaneity

Which of the following processes are spontaneous, and which are nonspontaneous?
(a) Freezing of water at 2 °C 
(b) Corrosion of iron metal 
(c) Expansion of a gas to fill the available volume
(d) Separation of an unsaturated aqueous solution of potassium chloride into solid KCl and liquid water

Which of the following processes are spontaneous and which are nonspontaneous: (a) the ripening of a banana

A standard air conditioner involves a refrigerant that is typically now a fluorinated hydrocarbon, such as CH2F2. An air-conditioner refrigerant has the property that it readily vaporizes at atmospheric pressure and is easily compressed to its liquid phase under increased pressure. The operation of an air conditioner can be thought of as a closed system made up of the refrigerant going through the two stages shown here (the air circulation is not shown in this diagram). 
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/5d14639fa3655013-1667390153941.jpg" alt="" /> 
During expansion, the liquid refrigerant is released into an expansion chamber at low pressure, where it vaporizes. The vapor then undergoes compression at high pressure back to its liquid phase in a compression chamber. (e) Suppose that a house and its exterior are both initially at 31 °C. Some time after the air conditioner is turned on, the house is cooled to 24 °C. Is this process spontaneous or nonspontaneous?

For the melting point of sodium chloride, ΔHfusion = 28.16 kJ/mol and ΔSfusion = 26.22 J/(K·mol). Does NaCl melt at 1100 K? Calculate the melting point of NaCl.

A reaction that requires a continuous energy source to happen is classified as an unnatural process and is nonspontaneous.&#160;

Trouton's rule says that the ratio of the molar heat of vapor-ization of a liquid to its normal boiling point (in kelvin) is approximately the same for all liquids: ∆Hvap/Tbp ≈ 88 J/(K*mol) 
(a) Check the reliability of Trouton's rule for the liquids listed in the following table.

When rolling a pair of dice, there are two ways to get a point total of 3(1+2;2+1) but only one way to get a point total of 2(1+1). How many ways are there of getting point totals of 4 to 12? What is the most probable point total?

Consider a system that consists of two standard playing dice, with the state of the system defined by the sum of the values shown on the top faces.

(f) Calculate the absolute entropy of the two-dice system.

The system consists of 2.00 mol of water.

Correct, the entropy change of the surroundings is determined by the energy dispersed into the surroundings and the absolute temperature.

The system consists of 2.00 mol of water and the defining equation includes the term &#x2212;qsys.

The defining equation includes the term &#x2212;qsys.

&#916;Ssurroundings = &#x2212;qsys/Tsurr. &#916;Hfus = 6.02 kJ/mol.

Calculate &#916;Ssurr (in units of J/K) for the process in which 2.00 mol of water are placed into a freezer at &#x2212;10.0&#x2103;.

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Thermodynamics&#160;is the branch of physical science concerned with heat and its transformations to and from other forms of energy.&#160;

Entropy

Entropy is the disorder or chaos associated with a system’s inability to convert thermal energy into mechanical work.&nbsp;

Gibbs Free Energy

Gibbs Free Energy (&#916;G)&#160;represents energy associated with a chemical reaction that can be used to do work.