Which ionic compound has the largest value of lattice enthalpy?

A. MgS

B. MgO

C. CaBr₂

D. NaF

Which combination of ΔH ^θ and ΔS ^θ will result in a non-spontaneous reaction at all temperatures?

Which combination gives the standard hydration enthalpy of ${\mathrm{Na}}^{+} \left(\mathrm{g}\right)$?

A.  $4+359+790$

B.  $4+359-790$

C.  $-4-359+790$

D.  $4-359+790$

Which equation represents the lattice enthalpy of magnesium sulfide?

A. MgS (s) → Mg (g) + S (g)

B. MgS (s) → Mg⁺ (g) + S^– (g)

C. MgS (s) → Mg²⁺ (g) + S^2– (g)

D. MgS (s) → Mg (s) + S (s)

The table shows the variation of standard Gibbs energy with temperature for a reversible reaction.

$∆G^{⦵}=∆H^{⦵}\mathit{-}T∆S^{⦵}$

$∆G^{⦵}=\mathit{-}RT \ln K$

What can be concluded about the reaction?

A.  Equilibrium shifts left as temperature increases.

B.  The forward reaction is more spontaneous below 300 K.

C.  Entropy is higher in the products than in the reactants.

D.  K_c decreases as temperature increases.

Which value represents the lattice enthalpy, in kJ mol⁻¹, of strontium chloride, SrCl₂?

A.     – (–829) + 164 + 243 + 550 + 1064 – (–698)

B.     –829 + 164 + 243 + 550 + 1064 – 698

C.     – (–829) + 164 + 243 + 550 + 1064 – 698

D.     –829 + 164 + 243 + 550 + 1064 – (–698)

In which of the following situations is the forward reaction spontaneous?

A.  The equilibrium constant is greater than one under standard conditions.

B.  The cell potential is negative.

C.  The Gibbs free energy change of the reverse reaction is negative.

D.  The entropy change of the universe for the forward reaction is negative.

In which reaction does entropy decrease?

A.  NaCl (s) → NaCl (aq)

B.  Zn (s) + H₂SO₄(aq) → ZnSO₄(aq) + H₂(g)

C.  NH₃(g) + HCl (g) → NH₄Cl (s)

D.  CuCO₃(s) → CuO (s) + CO₂(g)

What are the signs of ΔH and ΔS for a reaction that is non-spontaneous at low temperatures but spontaneous at high temperatures?

Which ion’s hydration energy is the most exothermic?

A.     Li⁺

B.     Na⁺

C.     Br^–

D.     I^–

Which represents electron affinity?

A.  Al²⁺(g) → Al³⁺(g) + e⁻

B.  C (g) + e⁻ → C⁻(g)

C.  Cl₂(g) → 2Cl (g)

D.  S (s) → S⁺(g) + e⁻

Which equation represents the standard enthalpy of atomization of bromine, Br₂?

A. $\frac{1}{2}$Br₂ (l) → Br (g)

B. Br₂ (l) → 2Br (g)

C. Br₂ (l) → 2Br (l)

D. $\frac{1}{2}$Br₂ (l) → Br (l)

What is the enthalpy of solution of MgF₂(s) in kJ mol⁻¹?

Lattice enthalpy of MgF₂(s) = 2926 kJ mol⁻¹

Hydration enthalpy of Mg²⁺(g) = −1963 kJ mol⁻¹

Hydration enthalpy of F⁻(g) = −504 kJ mol⁻¹

A.     2926 − 1963 + 2(−504)

B.     2926 − 1963 − 504

C.     −2926 − (−1963) − (−504)

D.     −2926 − (−1963) − 2(−504)

What is the order of increasing (more exothermic) enthalpy of hydration?

Xⁿ⁺ (g) → Xⁿ⁺ (aq)

A.  Ca²⁺, Mg²⁺, K⁺, Na⁺

B.  Na⁺, K⁺, Mg²⁺, Ca²⁺

C.  K⁺, Na⁺, Ca²⁺, Mg²⁺

D.  Mg²⁺, Ca²⁺, Na⁺, K⁺

Which compound has the largest value of lattice enthalpy?

A.  Na₂O

B.  K₂O

C.  Na₂S

D.  K₂S

What are the signs of ΔH^Θ and ΔS^Θ for the reaction, which is spontaneous at low temperature and non-spontaneous at very high temperature?

ΔG^Θ = ΔH^Θ − TΔS^Θ

SO₃ (g) + CaO (s) → CaSO₄ (s)

Which system has the most negative entropy change, ΔS, for the forward reaction?

A.     N₂(g) + 3H₂(g) $\rightleftharpoons$ 2NH₃(g)

B.     CaCO₃(s) → CaO(s) + CO₂(g)

C.     2S₂O₃²⁻(aq) + I₂(aq) → S₄O₆²⁻(aq) + 2I^–(aq)

D.     H₂O(l) → H₂O(g)

Which statements are correct for ionic compounds?

I.   Lattice energy increases as ionic radii increase.
II.  Within the same group, the melting point of salts tends to decrease as the radius of the cation increases.
III. Solubility in water depends on the relative magnitude of the lattice energy compared to the hydration energy.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Which term in the expression ΔG^⦵ = ΔH^⦵ − TΔS^⦵ is an indirect measure of the entropy change of the surroundings when divided by T?

A.  ΔG^⦵

B.  ΔH^⦵

C.  ΔS^⦵

D.  −TΔS^⦵

Which change is exothermic?

A.  $\frac{1}{2}$Cl₂ (g) → Cl (g)

B.   K (g) → K⁺ (g) + e⁻

C.   KCl (s) → K⁺ (g) + Cl⁻ (g)

D.   Cl (g) + e⁻ → Cl⁻ (g)

Which represents the enthalpy change of hydration of the chloride ion?

Which statement is correct?

A.     If ΔH < 0, reaction is always spontaneous.

B.     If ΔH > 0, reaction is never spontaneous.

C.     If ΔS < 0, reaction can be spontaneous if temperature is low enough.

D.     If ΔS < 0, reaction can be spontaneous if temperature is high enough.

The Born-Haber cycle for potassium oxide is shown below:

Which expression represents the lattice enthalpy in kJ mol^–1?

A.     –361 + 428 + 838 + 612

B.     –(–361) + 428 + 838 + 612

C.     –361 + 428 + 838 – 612

D.     –(–361) + 428 + 838 – 612

Which substance has the highest lattice enthalpy?

A.  $\text{KCl}$

B.  ${\text{CaCl}}_2$

C.  $\text{KF}$

D.  ${\text{CaF}}_{\text{2}}$

Which equation represents lattice enthalpy?

A. NaCl (g) → Na⁺ (g) + Cl⁻ (g)

B. NaCl (s) → Na⁺ (g) + Cl⁻ (g)

C. NaCl (s) → Na⁺ (aq) + Cl⁻ (aq)

D. NaCl (s) → Na⁺ (s) + Cl⁻ (s)

Which equation represents hydration enthalpy?

A.  Na⁺(g) → Na⁺(aq)

B.  Na⁺(aq) → Na⁺(g)

C.  NaCl (s) → NaCl (aq)

D.  NaCl (aq) → NaCl (s)

Consider the Born–Haber cycle for the formation of sodium oxide:

What is the lattice enthalpy, in kJ mol⁻¹, of sodium oxide?

A.  414 + 2(108) + 249 + 2(496) − 141 + 790

B.  414 + 2(108) + 249 + 2(496) + 141 + 790

C.  −414 + 2(108) + 249 + 2(496) − 141 + 790

D.  −414 − 2(108) − 249 − 2(496) + 141 − 790

What is the standard enthalpy of formation, in kJ mol^–1, of IF (g)?

IF₇ (g) + I₂ (s) → IF₅ (g) + 2IF (g)        ΔH${}^{\theta }$ = –89 kJ

ΔH${}_f^{\theta }$ (IF₇) = –941 kJ mol^–1

ΔH${}_f^{\theta }$ (IF₅) = –840 kJ mol^–1

A. –190

B. –95

C. +6

D. +95

Which equation represents enthalpy of hydration?

A.     Na(g) → Na⁺(aq) + e⁻

B.     Na⁺(g) → Na⁺(aq)

C.     NaCl(s) → Na⁺(g) + Cl⁻(g)

D.     NaCl(s) → Na⁺(aq) + Cl⁻(aq)

Which is correct for the reaction H₂O (g) → H₂O (l) ?

A. Enthalpy increases and entropy increases.

B. Enthalpy decreases and entropy increases.

C. Enthalpy increases and entropy decreases.

D. Enthalpy decreases and entropy decreases.

Which change has the greatest increase in entropy?

A. CO₂ (s) → CO₂ (g)

B. CO₂ (g) → CO₂ (l)

C. CO₂ (g) → CO₂ (s)

D. CO₂ (l) → CO₂ (s)

Which reaction becomes more spontaneous as temperature increases?

A.  ${\mathrm{CaCO}}_3 \left(\mathrm{s}\right)\to \mathrm{CaO} \left(\mathrm{s}\right)+{\mathrm{CO}}_2 \left(\mathrm{g}\right)$

B.  ${\mathrm{N}}_2 \left(\mathrm{g}\right)+3{\mathrm{H}}_2 \left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3 \left(\mathrm{g}\right)$

C.  $3{\mathrm{CO}}_2 \left(\mathrm{g}\right)+4{\mathrm{H}}_2\mathrm{O} \left(\mathrm{g}\right)\to {\mathrm{C}}_3{\mathrm{H}}_8 \left(\mathrm{g}\right)+5{\mathrm{O}}_2 \left(\mathrm{g}\right)$

D.  ${\mathrm{SO}}_2 \left(\mathrm{g}\right)+{\mathrm{H}}_2{\mathrm{O}}_2 \left(\mathrm{l}\right)\to {\mathrm{H}}_2{\mathrm{SO}}_4 \left(\mathrm{l}\right)$

Which reaction has the greatest increase in entropy of the system?

A. HCl (g) + NH₃ (g) → NH₄Cl (s)

B. (NH₄)₂Cr₂O₇ (s) → Cr₂O₃ (s) + N₂ (g) + 4H₂O (g)

C. CaCO₃ (s) → CaO (s) + CO₂ (g)

D. I₂ (g) → I₂ (s)

Which change results in the largest negative value of ΔS?

A.  C₂H₅OH (l) + SOCl₂(l) → C₂H₅Cl (l) + SO₂(g) + HCl (g)

B.  CaCO₃(s) → CaO (s) + CO₂(g)

C.  H₂O (l) → H₂O (s)

D.  NH₃(g) + HCl (g) → NH₄Cl (s)

The combustion of glucose is exothermic and occurs according to the following equation:

C₆H₁₂O₆ (s) + 6O₂ (g) → 6CO₂ (g) + 6H₂O (g)

Which is correct for this reaction?