Using the following thermochemical data- C s - O 2 g - CO 2 g - H -94-0 kcalH 2 g -1-2 O 2 g - H 2 O l - H -68-0 kcalCH 3 COOH l -2 O 2 g - 2 CO 2 g -2 H 2 O l - H -210-0 kcalthe heat of formation of acetic acaid is -A- -114 kcalB- 114 kcalC- 116 kcalD- -116 kcal

The correct option is A 114 kcalGiven reactions are C(s)+O_2(g)→ CO_2(g) Δ H= 94.0 kcal....(1) H_2(g)+1/2O_2(g)→ H_2O(l) Δ H= 68.0 kcal...(2) CH_3CO ...

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Byju's Answer

Standard XII

Chemistry

Heat of Formation

Using the fol...

Question

Using the following thermochemical data,
$C (s) + O_{2} (g) \to C O_{2} (g) Δ H = - 94.0 k c a l$
$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) Δ H = - 68.0 k c a l$
$C H_{3} C O O H (l) + 2 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l) Δ H = - 210.0 k c a l$
the heat of formation of acetic acaid is :

116 kcal

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-116 kcal

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-114 kcal

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114 kcal

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Solution

The correct option is C -114 kcal
Given reactions are $C (s) + O_{2} (g) \to C O_{2} (g) Δ H = - 94.0 k c a l . . . . (1)$

$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) Δ H = - 68.0 k c a l . . . (2)$

$C H_{3} C O O H (l) + 2 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l) Δ H = - 210.0 k c a l . . . . (3)$

reversing the reaction 3, we get
$2 C O_{2} (g) + 2 H_{2} O (l) \to C H_{3} C O O H (l) + 2 O_{2} (g) Δ H = + 210.0 k c a l . . . . (4)$

multipling equation 1 and 2 by 2 we get,
$2 C (s) + 2 O_{2} (g) \to 2 C O_{2} (g) Δ H = 2 \times - 94.0 k c a l . . . . . . . .5$
$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (l) Δ H = 2 \times - 68.0 k c a l . . . . . . .6$

now add eqn 4, 5 and 6 to obtain
$2 C (s) + 2 H_{2} (g) + O_{2} (g) \to C H_{3} C O O H (l)$

so the heat of formation of acetic acid $= 210.0 + 2 (- 94.0) + 2 (- 68.0)$
$= - 114 k c a l$

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Similar questions

Q. Using the following thermochemical data

C (S) + O_{2} (g) \to C O_{2} (g)

Δ H = - 94.0 K c a l

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l)

Δ H = - 68.0 K c a l

C H_{3} C O O H (l) + 2 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l)

Δ H = - 210.0 K c a l

The heat of formation of acetic acid is

Q. Using the following thermochemical data,

C (s) + O_{2} (g) \to C O_{2} (g) Δ H = - 94.0 k c a l

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) Δ H = - 68.0 k c a l

C H_{3} C O O H (l) + 2 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l) Δ H = - 210.0 k c a l

the heat of formation of acetic acid is :

Q. Given,

C (s) + O_{2} (g) \to C O_{2} (g) Δ H = - 94.2 k c a l

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) Δ H = - 68.3 k c a l

C H_{4} (g) + 2 O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l) Δ H = - 210.8 k c a l

The heat of formation of methane in kcal will be :

Q. Given,

C (s) + O_{2} (g) \to C O_{2} (g) Δ H = + 94.2 k c a l

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) + 68.3 Δ H = k c a l

C H_{4} (g) + 2 O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l) Δ H = + 210.8 k c a l

The heat of formation of methane in

k c a l

will be:

Q. Calculate the heat of formation of acetic acid from the following data.

C H_{3} C O O H (l) + 2 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l), △ H = - 207.9 K c a l

C (s) + O_{2} (g) \to C O 2 (g) △ H = - 94.48 K c a l

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l) △ H = - 68.4 K c a l

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Heat of Formation

Standard XII Chemistry

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Using the following thermochemical data, C(s)+O2(g)→CO2(g) ΔH=−94.0 kcal H2(g)+12O2(g)→H2O(l) ΔH=−68.0 kcal CH3COOH(l)+2O2(g)→2CO2(g)+2H2O(l) ΔH=−210.0 kcal the heat of formation of acetic acaid is :