Given Cgraphite-O2g - CO2g-f H-393-5 kJ mol-1H2g-1-2O2g - H2O l-f H-285-8 kJ mol-1CO2g-2H2Ol - CH4g-2O2g-f H-890-3 kJ mol-1Based on the above thermochemical equations- the value of -f H- at 298 K for the reactionCgraphite-2H2g - CH4g will be-

C_(graphite)+O_2 (g) → CO_2 (g); nbsp; Δ_f H^∘= 393.5 kJmol^ 1……… (1) H_2(g)+1/2O_2 (g) → H_2O(l); nbsp;Δ_f H^∘= 285.8 kJmol^ 1……… (2) CO_2(g)+2H_2O(l ...

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Standard XII

Chemistry

Lattice Energy

Given Cgraphi...

Question

Given $C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g);$

$Δ_{f} H^{\circ} = - 393.5 k J m o l^{- 1}$

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

$Δ_{f} H^{\circ} = - 285.8 k J m o l^{- 1}$

$C O_{2} (g) + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g)$

$Δ_{f} H^{\circ} = + 890.3 k J m o l^{- 1}$

Based on the above thermochemical equations, the value of $Δ_{f} H^{\circ}$ at 298 K for the reaction

$C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)$ will be:

+ 144.0 k J m o l^{- 1}

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- 74.8 k J m o l^{- 1}

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- 144.0 k J m o l^{- 1}

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+ 74.8 k J m o l^{- 1}

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Solution

The correct option is B $- 74.8 k J m o l^{- 1}$
$C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g)$ ; $Δ_{f} H^{\circ} = - 393.5 k J m o l^{- 1} \dots \dots \dots (1)$

$H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l)$ ; $Δ_{f} H^{\circ} = - 285.8 k J m o l^{- 1} \dots \dots \dots (2)$

$C O_{2} (g) + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g)$ ; $Δ H_{f}^{\circ} = + 890.3 k J m o l^{- 1} \dots \dots \dots (3)$

$C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)$ ; $Δ H = ? \dots \dots \dots (4)$

[Eq.(1) + Eq.(3)] + $[2 \times E q . (2)] = E q . (4)$

$∴ [Δ H_{1} + Δ H_{3}] + [2 \times Δ H_{2}] = Δ H_{4}$

$[(- 393.5) + (890.3)] + [2 (- 285.8)] = - 74.8 k J m o l^{- 1}$

$= - 74.8 k J m o l^{- 1}$

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Similar questions

Q. Given

C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g);

Δ_{f} H^{\circ} = - 393.5 k J m o l^{- 1}

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

Δ_{f} H^{\circ} = - 285.8 k J m o l^{- 1}

C O_{2} (g) + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g)

Δ_{f} H^{\circ} = + 890.3 k J m o l^{- 1}

Based on the above thermochemical equations, the value of

Δ_{f} H^{\circ}

at 298 K for the reaction

C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)

will be:

Q. Given,

C_{(g r a p h i t e s)} + O_{2} (g) \to C O_{2} (g)

Δ_{r} H^{\circ} = - 393.5 k J m o l^{- 1}

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

Δ_{r} H^{\circ} = - 285.8 k J m o l^{- 2}

C O_{2} (g + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g)

Δ_{r} H^{\circ} = + 890.3 k J m o l^{- 1}

Based on the above thermochemical equations, the value of

Δ_{r} H^{\circ}

at 298K for the reaction,

C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)

will be

Q. Given,

C_{(g r a p h i t e s)} + O_{2} (g) \to C O_{2} (g)

Δ_{r} H^{\circ} = - 393.5 k J m o l^{- 1}

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

Δ_{r} H^{\circ} = - 285.8 k J m o l^{- 2}

C O_{2} (g + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g)

Δ_{r} H^{\circ} = + 890.3 k J m o l^{- 1}

Based on the above thermochemical equations, the value of

Δ_{r} H^{\circ}

at 298K for the reaction,

C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)

will be

Q. Given,

C_{(g r a p h i t e)} + O_{2} (g) \to C O_{2} (g); Δ_{r} H^{o} = - 393.5 k J m o l^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ_{r} H^{o} = - 285.8 k J m o l^{- 1}

C O_{2} (g) + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g); Δ_{r} H^{o} = + 890.3 k J m o l^{- 1}

Based on the above thermochemical equations, the value of

Δ_{r} H^{o}

298 K

for the reaction

C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)

will be:

Q. Given,

C_{(g r a p h i t e} + O_{2} (g) \to C O_{2} (g); Δ_{r} H^{o} = - 393.5 k J m o l^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ_{r} H^{o} = - 285.8 k J m o l^{- 1}

C O_{2} (g) + 2 H_{2} O (l) \to C H_{4} (g) + 2 O_{2} (g); Δ^{r} H 6 o = + 890.3 k J m o l^{- 1}

Based on the above thermochemical wquations, the value of

D e l t a_{r} H^{o}

298 K

for the reaction,

C_{(g r a p h i t e)} + 2 H_{2} (g) \to C H_{4} (g)

will be:

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Given C(graphite)+O2(g)→CO2(g); ΔfH∘=−393.5 kJmol−1 H2(g)+12O2(g)→H2O(l) ΔfH∘=−285.8 kJmol−1 CO2(g)+2H2O(l)→CH4(g)+2O2(g) ΔfH∘=+890.3 kJmol−1 Based on the above thermochemical equations, the value of ΔfH∘ at 298 K for the reaction C(graphite)+2H2(g)→CH4(g) will be: