Calculate the standard enthalpy of formation of CH3OHI from the following data - CH3OH I -32O2g- CO2g-2H2Ol- rH-726 kJ mpl-1 Cgraphite-O2g - CO2g- cH- 393 kJ mol-1 H2g-12O2g - H2Ol- fH-286 kJ mol-1

On reversing the first equation we get, #160; CO_2(g) + 2H_2O(l) → CH_3OH(l) + 32O_2(g) ; Δ_rH^θ = +726kJmol^ 1 #160;(on reversing the reaction, t ...

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Standard XII

Chemistry

Heat of Formation

Calculate the...

Question

Calculate the standard enthalpy of formation of $C H_{3} O H (I)$ from the following data :
$C H_{3} O H (I) + \frac{3}{2} O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l); △_{r} H^{θ} = - 726 k J m p l^{- 1}$
$C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g); △_{c} H^{θ} = - 393 k J m o l^{- 1}$
$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); △_{f} H^{θ} = - 286 k J m o l^{- 1}$

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Solution

On reversing the first equation we get,
$C O_{2} (g) + 2 H_{2} O (l) \to C H_{3} O H (l) + \frac{3}{2} O_{2} (g)$ ; $Δ_{r} H^{θ} = + 726 k J m o l^{- 1}$ (on reversing the reaction, the sign of $Δ H$ also reverses)

The second equation remains as such,
$C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g); Δ_{c} H^{θ} = - 393 k J m o l^{- 1}$

On multiplying equation three by 2 we get,

$2 H_{2} (g) + O_{2} (g) \to 2 H_{2} O (l); 2 Δ_{f} H^{θ} = 2 \times - 286 k J m o l^{- 1} = - 572 k J m o l^{- 1}$

On adding these three equations we get,

$C_{(g r a p h i t e)} + 2 H_{2} (g) + \frac{1}{2} O_{2} (g) \to C H_{3} O H (l)$

Enthalpy of formation of $C H_{3} O H = Δ_{f} H = Δ_{r} H^{θ} + Δ_{c} H^{θ} + 2 Δ_{f} H^{θ}$

$Δ_{f} H = + 726 - 393 - 572 k J m o l^{- 1} = - 239 k J m o l^{- 1}$

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Similar questions

Calculate the standard enthalpy of formation of CH₃OH₍_l₎ from the following data:

CH₃OH₍_l₎ + O₂₍_g₎ CO₂₍_g₎ + 2H₂O₍_l₎ ; Δ_rH^θ = –726 kJ mol^–1

C₍_g₎ + O₂₍_g₎ CO₂₍_g₎ ; Δ_cH^θ = –393 kJ mol^–1

H₂₍_g₎ +O₂₍_g₎ H₂O₍_l₎ ; Δ_fH^θ = –286 kJ mol^–1.

C H_{3} O H (1) + \frac{3}{2} O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (I); Δ, H^{⊖} = - 726 k J m o l^{- 1}

C (g r a p h i t e) + O_{2} (g) \to C O_{2} (g); Δ_{c} H^{⊖} = - 393 k J m o l^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (I); Δ_{f} H^{⊖} = - 286 k J m o l^{- 1}

Calculate the standard enthalpy of formation of

{C H}_{3} O H (l)

from the following data:

Q. Calculate the standard enthalpy of formation of

C H_{3} O H (l)

from the following data.

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

;

Δ H^{o} = - 726

m o l^{- 1}

C(graphite)

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

Δ_{c} H^{0} = - 393

m o l^{- 1}

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

Δ_{t} H^{o} = - 286

m o l^{- 1}

Q. Calculate the standard enthalpy of formation of

C H_{3} O H

from the following data.

C H_{3} O H (l) + \frac{3}{2} O_{2} (g) \to C O_{2} (g) + 2 H_{2} O (l); Δ_{r} H^{⊖} = - 726 k J m o l^{- 1}

C (g) + O_{2} (g) \to C O_{2} (g); Δ_{c} H^{⊖} = - 393 k J m o l^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ_{f} H^{⊖} = - 286 k J m o l^{- 1}

Q. Calculate enthalpy for formation of ethylene from the following data:

(I)

C (g r a p h i t e) + O_{2} (g) \to C O_{2} (g); Δ H = - 393.5 k J

(II)

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ H = - 286.2 k J

(III)

C_{2} H_{4} (g) + 3 O_{2} (g) \to 2 C O_{2} (g) + 2 H_{2} O (l); Δ H = - 1410.8 k J

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Calculate the standard enthalpy of formation of CH3OH(I) from the following data :CH3OH(I)+32O2(g)→CO2(g)+2H2O(l);△rHθ=−726kJmpl−1C(graphite)+O2(g)→CO2(g);△cHθ=−393kJmol−1H2(g)+12O2(g)→H2O(l);△fHθ=−286kJmol−1