EASY

Earn 100

Give the unit of electron gain enthalpy.

Important Questions on Energetics (Thermochemistry AHL)

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The ionization enthalpy of

{Na}^{+}

formation from

{Na}_{(g)}

495.8 kJ {mol}^{- 1},

while the electron gain enthalpy of

Br

- 325.0 kJ {mol}^{- 1}

. Given the lattice enthalpy of

NaBr

- 728.4 kJ {mol}^{- 1}

. The energy for the formation of

NaBr

ionic solid is

(-)_____10^{- 1} kJ {mol}^{- 1}

HARD

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

For one mole of NaCl(s) the lattice enthalpy is

${Na}_{(s)} + \frac{1}{2} {Cl}_{2} (g) \overset{+ 108.4 kJ / mol}{⟶} {Na}_{(s)} + \frac{1}{2} {Cl}_{2} (g) \overset{+ 495.6 kJ / mol}{⟶} {Na}_{(g)}^{+} + \frac{1}{2} {Cl}_{2} (g) \overset{121 kJ / mol}{⟶}$

${Na}_{(g)}^{+} + Cl (g) \overset{- 348.6 kJ / mol}{⟶} {Na}_{(g)}^{+} + {Cl}_{(g)}^{-} \overset{{ΔH}^{0} altice}{⟶} Nacl$ (solid) $\underset{- 411.2 kJ / mol}{\leftarrow} {Na}_{(s)} + \frac{1}{2} {Cl}_{2} (g)$

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The elements with the highest and the lowest enthalpy of atomisation respectively, for first row transition elements are:

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

In which of the following thermochemical changes, the

∆

H° is always negative?

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The heat of atomisation of

{PH}_{3 (g)} is 228 kcal {mol}^{- 1} and that of P_{2} H_{4 (g)} is 355 kcal {mol}^{- 1}

. The energy of the P

-

P bond is _____

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Consider the Born-Haber cycle for the formation of an ionic compound given below and identify the compound

Z

formed.

[\begin{array}{l} M (s) \overset{{ΔH}_{1}}{\to} M (g) \overset{{ΔH}_{2}}{\to} M^{+} (g) \\ \frac{1}{2} X_{2} (g) \overset{{ΔH}_{3}}{\to} X (g) \overset{{ΔH}_{4}}{\to} X^{-} (g) \end{array}] \overset{{ΔH}_{5}}{\to} Z

HARD

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Which of the following parameter cannot be estimated by using Born - Haber cycle?

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Which of the following is INCORRECT regarding Born-Haber cycle for the formation of

NaCl

HARD

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The heat of atomisation of PH₃(g) is 228 kcal mol^-1 and that P₂H₄(g) is 355 kcal mol^-1 . The energy of the P - P is (in kcal):

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The enthalpy of atomization of

{CH}_{4}

and

C_{2} H_{6}

are

360

and

620 kcal {mol}^{- 1}

, respectively. The

C — C

bond energy is expected to be?

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The enthalpy change

(∆ H)

for the process

N_{2} H_{4} (g) \to 2 N (g) + 4 H (g) is 1724 kJ {mol}^{- 1} .

If the bond energy of

N - H

bond in ammonia is

391 kJ {mol}^{- 1}

, what is the bond energy of

N - N

bond in

N_{2} H_{4}

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Born-Haber cycle is used to determine ______.

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

C a O

and

N a C l

have the same crystal structure and approximately the same ionic radii. If

U

is the lattice energy of

NaCl

, the approximate lattice of

CaO

is?

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Which of the following statements is incorrect about the Born–Haber cycle?

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Enthalpy of atomization of

C_{2} H_{6} (g)

and

C_{3} H_{8} (g)

are

620

and

880 kJ {mol}^{- 1}

respectively. The

C - C

and

C - H

bond energies are respectively

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The heat of atomisation of

P H_{3} (g)

228 kcal {mol}^{- 1}

and that of

P_{2} H_{4} (g)

335 kcal {mol}^{- 1}

. The energy of

P - P

bond is:

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

If for

H_{2} (g) ⇌ 2 H (g); ΔH = 104 kcal

, heat of atomisation of hydrogen is:

EASY

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

The Born-Haber cycle may be used to calculate:

MEDIUM

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Enthalpy of solution of

NaCl (s)

+ 4 kJ {mol}^{- 1}

and enthalpy of hydration is

- 784 kJ {mol}^{- 1}

. Lattice enthalpy of

NaCl (s)

will be _____

kJ {mol}^{- 1}

HARD

Chemistry>Physical Chemistry>Energetics (Thermochemistry AHL)>Born- Haber Cycle

Enthalpy of atomisation of

C_{2} H_{6} (g)

and

C_{3} H_{8} (g)

are

620 kJ {mol}^{- 1}

and

880 kJ {mol}^{- 1}

. Therefore,

Give the unit of electron gain enthalpy.

Important Questions on Energetics (Thermochemistry AHL)

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