Thermodynamics Test

Question 1
1 / -0

Which of the following conditions guarantee a spontaneous reaction?

A
Positive $$\triangle H$$, positive $$\triangle S$$

B
Positive $$\triangle H$$, negative $$\triangle S$$

C
Negative $$\triangle H$$, negative $$\triangle S$$

D
Negative $$\triangle H$$, positive $$\triangle S$$

E
None of the above

Question 2
1 / -0

The heat capacity for aluminum is $$\displaystyle 0.89{ Jg }^{ -10 }{ C }^{ -1 }$$, for iron is $$\displaystyle 0.45{ Jg }^{ -10 }{ C }^{ -1 }$$, and for zinc is $$\displaystyle 0.39{ Jg }^{ -10 }{ C }^{ -1 }$$. If 100 J of heat energy was added to a10 g sample of each of the metals, which of the following would be true?

A
$$\displaystyle Al$$ would have the largest temperature increase.

B
$$\displaystyle Fe$$ would have the largest temperature increase.

C
$$\displaystyle Zn $$ would have the largest temperature increase.

D
$$\displaystyle Fe$$ and $$\displaystyle Zn$$ would have the same increase.

E
All three metals would have the same temperature increase.

Question 3
1 / -0

To which portion of the heating curve for water does $$\Delta {H}_{vap}$$ apply?

A
$$A-B$$

B
$$B-C$$

C
$$C-D$$

D
$$D-E$$

Question 4
1 / -0

$$C_v$$ for helium gas $$(He)$$ is $$(in J \ mol^{-1} \ K^{-1})$$

A
2.5

B
10.5

C
1.5

D
12.5

Question 5

1 / -0

Consider a spontaneous electrochemical cell between $$Cu$$ and $$Al$$. Predict what would happen if excess concentrated $$NaOH$$ were added to the cell with copper ions and a precipitate forms.

Standard Potential (V)	Reduction Half-Reaction
$$2.87$$	$$F_{2}(g) + 2e^{-} \rightarrow 2F^{-}(aq)$$
$$1.51$$	$$MnO_{4}^{-}(aq) + 8H^{+}(aq) + 5e^{-}\rightarrow Mn^{2+}(aq) + 4H_{2}O(l)$$
$$1.36$$	$$Cl_{2}(aq) + 3e^{-} \rightarrow 2Cl^{-}(aq)$$
$$1.33$$	$$Cr_{2}O_{7}^{2-} (aq) + 14H^{+}(aq) + 6e^{-} \rightarrow 2Cr^{3+}(aq) + 7H_{2}O(l)$$
$$1.23$$	$$O_{2}(g) + 4H^{+}(aq) + 4e^{-}\rightarrow 2H_{2}O(l)$$
$$1.06$$	$$Br_{2}(l) + 2e^{-} \rightarrow 2Br^{-}(aq)$$
$$0.96$$	$$NO_{3}^{-}(aq) + 4H^{+}(aq) + 3e^{-}\rightarrow NO(g) + H_{2}O(l)$$
$$0.80$$	$$Ag^{+}(aq) + e^{-} \rightarrow Ag(s)$$$
$$0.77$$	$$Fe^{3+} (aq) + e^{-} \rightarrow Fe^{2+}(aq)$$
$$0.68$$	$$O_{2}(g) + 2H^{+}(aq) + 2e^{-}\rightarrow H_{2}O_{2}(aq)$$
$$0.59$$	$$MnO_{4}^{-}(aq) + 2H_{2}O(l) + 3e^{-}\rightarrow MnO_{2}(s) + 4OH^{-}(aq)$$
$$0.54$$	$$I_{2}(s) + 2e^{-}\rightarrow 2I^{-}(aq)$$
$$0.40$$	$$O_{2}(g) + 2H_{2}O(l) + 4e^{-} \rightarrow 4OH^{-}(aq)$$
$$0.34$$	$$Cu^{2+}(aq) + 2e^{-} \rightarrow Cu(s)$$
$$0$$	$$2H^{+}(aq) + 2e^{-}\rightarrow H_{2}(g)$$
$$-0.28$$	$$Ni^{2+}(aq) + 2e^{-}\rightarrow Ni(s)$$
$$-0.44$$	$$Fe^{2+}(aq) + 2e^{-}\rightarrow Fe(s)$$
$$-0.76$$	$$Zn^{2+}(aq) + 2e^{-}\rightarrow Zn(s)$$
$$-0.83$$	$$2H_{2}O(l) + 2e^{-}\rightarrow H_{2}(g) + 2OH^{-}(aq)$$
$$1.66$$	$$Al^{3+}(aq) + 3e^{-}\rightarrow Al(s)$$
$$-2.71$$	$$Na^{+}(aq) + e^{-} \rightarrow Na(s)$$
$$-3.05$$	$$Li^{+}(aq) + e^{-}\rightarrow Li(s)$$

Voltage would increase since more ions can give up electrons.

Voltage will decrease since there will be less $$Cu^{2+}$$ ions in solution.

Voltage would stay the same since $$NaOH$$ is a strong electrolyte and will exist as a spectator ion.

Voltage would increase and then decrease as the addition of new ions reach equilibrium.

Question 6
1 / -0

ln which of the processes, does the internal energy of the system remain constant?

A
Adiabatic

B
Isochoric

C
Isobaric

D
Isothermal

Question 7
1 / -0

Given, sublimation and ionization energy of $$Na$$ are $$107\space kJ/mol$$ and $$502 \space kJ/mol$$ respectively and bond dissociation energy required for chlorine gas and its electron affinity energy are $$121\space kJ/mol$$ and $$-355\space kJ/mol$$. If $$\triangle H_{f}^{0}$$ is $$-411\space kJ/mol$$. What is its approximate lattice enthalpy?

A
$$-786\space kJ/mol$$

B
$$788\space kJ/mol$$

C
$$388\space kJ/mol$$

D
$$-508\space kJ/mol$$

Question 8
1 / -0

Correct mathematical formulation of first law of thermodynamics used in thermochemistry is :

A
$$\Delta H =\ \Delta U +\ \Delta n RT$$

B
$$\Delta U =\ \Delta H +\ \Delta n RT$$

C
$$\Delta H =\ \Delta U -\ \Delta n RT$$

D
$$\Delta H =\ -\Delta U +\ \Delta n RT$$

Question 9
1 / -0

To which portion of the heating curve for water does $$\Delta {H}_{fus}$$ apply?

A
$$A-B$$

B
$$B-C$$

C
$$C-D$$

D
$$D-E$$

Question 10
1 / -0

Based on knowledge of solid compounds and bond strengths, which of the following reactions is considered non-spontaneous due to the extremely high activation energy but once started becomes extremely spontaneous?

A
Dissolution of sodium hydroxide.

B
Creating a dilution of hydrochloric acid.

C
The burning of $$C_{20}H_{42}$$.

D
The synthesis of silver oxide.