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Standard XII

Chemistry

Heat Capacity

Using the giv...

Question

Using the given data and calculate the enthalpy of formation of acetone(g).

Bond enthalpy of :
$C - H = 415; C - C = 350; (C = O) = 730$
$(O = O) = 495.0; H - H = 435;$

$Δ_{s u b} H$ of C $= 720$

[All values in kJ mol $^{- 1}$ ]

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Solution

Given $- C - H = 415 k J / m o l$ $C - C = 350 K J / m o l$
$C = 0 = 730 K J / m o l$ $O - O = 495 K J / m o l$
$H - H = 435 K J / m o l$ $Δ H_{s u b}$ of $C = 720 K J / m o l$
$C (s) \to C (g) - Δ H = 720 K J / m o l$
$O$
$| |$
$3 C (g) + 3 H_{2} (g) + \frac{1}{2} O_{2} (g) \to C H_{3} - C - C H_{3}$
Heat of formation of Acetone $=$ [Bond energy of formation of bond]
$+$ [Bond energy of dissociation of bond]
$= [6 (C - H) + 2 (C - C) + 1 (C = 0)]$
$+ [3 {C (s) \to C (g)} + 3 (H - H) + \frac{1}{2} (0 - 0)]$
$= - [6 \times 415 + 2 \times 350 + 1 \times 730]$
$+ [3 \times 720 + 3 \times 435 + \frac{1}{2} \times 495]$
$= - [2490 + 700 + 730]$
$+ [2160 + 1305 + 2475]$
$= - 3920 K J + 37125 K J$
$= - 207.5 K J / m o l$
$∴$ Heat of formation of acetone is $- 207.5 K J / m o l$

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Similar questions

Q. Using the bond enthalpy data given below, calculate the enthalpy of formation of acetone (g)
Bond energy

C - H = 413.4 k J {m o l}^{- 1}

;
Bond energy

C - C = 347.0 k J {m o l}^{- 1}

;
Bond energy

C = O = 728.0 k J {m o l}^{- 1}

;
Bond energy

O = O = 495.0 k J {m o l}^{- 1}

;
Bond energy

H - H = 435.8 k J {m o l}^{- 1}

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Δ H_{s u b} C (s) = 718.4 k J {m o l}^{- 1}

Q. Enthalpy of formation of

C_{2} H_{6} = - 83 k J / m o l

Enthalpy of sublimation of graphite =

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Enthalpy of bond dissociation of

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C - H bond enthalpy =

414 k J / m o l

Calculate the bond enthalpy of C - C

Q. Compute the enthalpy of formation of liquid methyl alcohol in kJ

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{C H}_{3} O H = 38 k J / m o l

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Enthalphy of formation of gaseous atoms from the elements in their standard states are enthalpy of formation of gaseous atoms from the elements in their standard states are

H

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C

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715 kJ / mol ;

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C - H

\to

415 kJ/mol ;

C - O

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356 kJ / mol ;

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Q. Compute the enthalpy of formation of liquid methyl alcohol in kJ mol

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Enthalpy of vaporisation of liquid

C H_{3} O H = 38

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Enthalpy of formation of gaseous atoms from the elements in their standard states are

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C \to 715

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C - H \to 415

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Q. Using the data (all values are in

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= - 72

(ii) Enthalpy of formation of benzene

(l) = 49

(iii) Enthalpy of vaporization of benzene

(l) = 30

(iv) Resonance energy of benzene

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H = 218, C = 715

Average bond energy of

C - H = 415

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C - C

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Using the given data and calculate the enthalpy of formation of acetone(g). Bond enthalpy of :C−H=415;C−C=350;(C=O)=730 (O=O)=495.0;H−H=435; ΔsubH of C =720 [All values in kJ mol−1]

Using the given data and calculate the enthalpy of formation of acetone(g).

Bond enthalpy of :
$C - H = 415; C - C = 350; (C = O) = 730$
$(O = O) = 495.0; H - H = 435;$

$Δ_{s u b} H$ of C $= 720$

[All values in kJ mol $^{- 1}$ ]