The standard enthalpies of formation at 300 K for CCl 4 l - H 2 O g - CO 2 g and HCl g are -107-242-394- and -93 kJ mol -1 respectively-The value of - U for the reaction CCl 4 l -2 H 2 O g - CO 2 g -4 HCl g at 300 K is-A- -182-50 kJ mol -1B- -282-50 kJ mol -1C- -170 kJ mol -1D- -175 kJmol -1

The correct option is A 182.50 kJmol^ 1The reaction given is, CCl_4(l)+2H_2O(g)→ CO_2(g)+4HCl(g) So, Δ H=Δ H_f(CO_2,g)+4Δ H_f(HCl,g) Δ H_f(CCl_4,l) 2Δ H_f(H_2 ...

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Standard XII

Chemistry

CFSE in Octahedral and Tetrahedral Complexes

The standard ...

Question

The standard enthalpies of formation at 300 K for $C C l_{4} (l), H_{2} O (g), C O_{2} (g) a n d H C l (g)$ are -107, -242, -394, and -93 $k J m o l^{- 1}$ respectively. The value of $Δ U$ for the reaction
$C C l_{4} (l) + 2 H_{2} O (g) \to C O_{2} (g) + 4 H C l (g)$
at 300 K is:

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

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

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

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

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Solution

The correct option is C $- 182.50 k J m o l^{- 1}$
The reaction given is,
$C C l_{4} (l) + 2 H_{2} O (g) \to C O_{2} (g) + 4 H C l (g)$
So, $Δ H = Δ H_{f} (C O_{2}, g) + 4 Δ H_{f} (H C l, g) - Δ H_{f} (C C l_{4}, l) - 2 Δ H_{f} (H_{2} O, g)$
$\Rightarrow Δ H = (- 394 - 4 \times 93 + 107 + 2 \times 242) k J m o l^{- 1}$
$\Rightarrow Δ H = - 175 k J m o l^{- 1}$
We know,
$Δ H = Δ U + Δ n_{g} R T$
$\Rightarrow Δ U = Δ H - Δ n_{g} R T$
$= - 175 - (3) (8.314 \times 10^{- 3} k J K^{- 1} m o l^{- 1}) (300 K) \approx - 182.48 k J m o l^{- 1}$

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Similar questions

Q. The standard enthalpies of formation at 300 K for

C C l_{4} (l), H_{2} O (g), (C O_{2}) a n d H C l (g) a r e - 107, - 242, - 394 a n d - 93 k J m o l^{- 1},

respectively. The value of

△ U_{300}^{o}

for the reaction

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

Q. The standard enthalpies of formation at 300 K for

C C l_{4} (l), H_{2} O (g), C O_{2} (g) a n d H C l (g) a r e - 107, - 242, - 394 a n d - 93 k J m o l^{- 1},

respectively. The value of

△ U_{300}^{o}

for the reaction:

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

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

. Find the value of

x

(Take

R = 8.314 J K^{- 1} m o l^{- 1}

)

Q. The standard enthalpies of formation at

300 K

for

C C l_{4} (l), H_{2} O (g), C O_{2} (g)

and

H C l (g)

are

- 107, - 242, - 394

and

- 93 {kJ mol}^{- 1}

respectively. The value of

Δ U

for the following reaction at

300 K

is:

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

Q. The standard enthalpies of formation at 300 K for

C C l_{4} (l), H_{2} O (g), C O_{2} (g) a n d H C l (g) a r e - 107, - 242, - 394 a n d - 93 k J m o l^{- 1},

respectively. The value of

△ U_{300}^{o}

for the reaction:

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

Q. The standard heat of formation at

298 K

for

C {C l}_{4} (g), H_{2} O (g), {C O}_{2} (g), H C l (g)

are

- 25.5, - 57.8, - 94, 1, - 22.1

k c a l {m o l}^{- 1}

respectively, calculate

Δ H_{298}^{o}

for the reaction,

C {C l}_{4} (g) + 2 H_{2} O (g) ⟶ {C O}_{2} (g) + 4 H C l (g)

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The standard enthalpies of formation at 300 K for CCl4(l), H2O(g), CO2(g) and HCl(g) are -107, -242, -394, and -93 kJmol−1 respectively. The value of ΔU for the reaction CCl4(l)+2H2O(g)→CO2(g)+4HCl(g) at 300 K is:

The standard enthalpies of formation at 300 K for $C C l_{4} (l), H_{2} O (g), C O_{2} (g) a n d H C l (g)$ are -107, -242, -394, and -93 $k J m o l^{- 1}$ respectively. The value of $Δ U$ for the reaction
$C C l_{4} (l) + 2 H_{2} O (g) \to C O_{2} (g) + 4 H C l (g)$
at 300 K is: