(Solved by Humans)-For which process is S negative? a. Grinding a large crystal of

Question

?For which process is ?S?negative?
a. Grinding a large crystal of KCl to powder.

b. Evaporation of 1 mol of CCl₄(l).

c. Mixing 5 mL ethanol with 25 mL water.

d. Compressing 1 mol Ne at constant temperature from 1.5 L to 0.5 L.

e. Raising the temperature of 100 g Cu from 275 K to 295 K.

2.? The second law of thermodynamics states that:
A.the entropy of the universe is increasing.

B.the entropy of a perfect crystal is zero at 0 K.

C.the energy of the universe is increasing.

D.the entropy of the universe is constant.

E.the energy of the universe is constant.

3.? Assume that the enthalpy of fusion of ice is 6020 J/mol and does not vary appreciably over the temperature range 270-290 K. If one mole of ice at 0?C is melted by heat supplied from surroundings at 275?K, what is the entropy change in the surroundings, in J/K?
A.-22.1 B.22.1 C.21.9 D.0.0 E.-21.9

4.? Which of the following is true for exothermic processes?
a. ?S_surr?= -?H/T

b. ?S_surr?> 0

c. ?S_surr?= 0

d. ?S_surr?< 0

e. Two of these choices are correct.

5.? Given that ?H_vap?is 56.0?kJ/mol, and the boiling point is 83.4?C, 1 atm, if one mole of this substance is vaporized at 1 atm, calculate ?S_surr.
a. 0?

b.?-671 J/K mol?

c.?157 J/K mol

d. -157 J/K mol

e. 671 J/K mol

6.? Substance X has a heat of vaporization of 53.0?kJ/mol at its normal boiling point (423?C). For the process X(l) ? X(g) at 1 atm and 423?C calculate the value of ?S_univ.
a. -76.1 J/K mol?

b.?-125 J/K mol

c. 125 J/K mol

d. 76.1 J/K mol

e. 0

7.? Substance X has a heat of vaporization of 53.0?kJ/mol at its normal boiling point (423?C). For the process X(l) ? X(g) at 1 atm and 423?C calculate the value of ?G.
a. 0 J?

b.?76.1 J

c. 125 J

d. -76.1 J

e. -125 J

8.? For the process CHCl₃(s) ? CHCl₃(l), ?H? = 9.15?kJ/mol and ?S? = 43.9 J/mol/K. What is the melting point of chloroform?
a. -65 ?C?

b.?208 ?C

c. 129 ?C

d. 65 ?C

e. -129 ?C

9. ?S?is ______ for exothermic reactions and ______ for endothermic reactions.
unfavorable,favorable

cannot tell

unfavorable,unfavorable

favorable,?favorable

favorable,?unfavorable

10.? The melting point of water is 0?C at 1 atm pressure because under these conditions:
a. ?S?and ?S_surr?for the process H₂O(s) ? H₂O(l) are equal in magnitude and opposite in sign.

b. ?S?for the process H₂O(s) ? H₂O(l) is positive. ?S?and ?S_surr?for the process H₂O(s) ? H₂O(l) are both positive.

c. ?G?is positive for the process H₂O(s) ? H₂O(l).

d. None of these is correct.

11.? For a certain process at 355 K, ?G?= -11.0?kJ and ?H?= -9.2 kJ. Therefore, ?S?for the process is:
a. 5.1 J/K mol

b. 25.9 J/K mol

c. -5.1 J/K mol

d. 0 J/K mol

e. -25.9 J/K mol

12.? For the process of a certain liquid vaporizing at 1 atm, ?H?_vap?= 51.0?kJ/mol and ?S?_vap=?74.1?J/mol K. Assuming these values are independent of?T, what is the normal boiling point of this liquid?
a. 961 ?C?b.?0.688 ?C?c.?688 ?C?d.?415 ?C?e.?None of these choices are correct.

13.?

Given the following data, calculate the normal boiling point for formic acid (HCOOH).

A. 0.39 ?C?B.?390 ?C?C.?279 ?C?D.?663 ?C?E.?117 ?C

14.? The following reaction takes place at 120?C: H₂O(l) ? H₂O(g) ?H?=?44.0?kJ/mol ?S?=?0.119?kJ/mol K

Which of the following must be true?

A. ?G?< 0 B.?The reaction is not spontaneous. C.??G?= 0 D.?The reaction is spontaneous. E.?Two of these choices are correct.

15.? The third law of thermodynamics states:
A.The entropy is zero at 0 K for a perfect crystal.

B.The entropy of the universe equals the sum of the entropy of system and surroundings.

C.The absolute entropy of a substance decreases with increasing temperature.

D.The entropy of the universe is increasing.

E.The entropy of the universe is constant.