The standard enthalpies of formation at 300 K for CCl 4 l - H 2 O g - CO 2 and HCl g are -107-242-394 and -93 kJ mol -1-respectively- The value of U 3000 for the reactionCCl 4 l -2 H 2 O g - CO 2 g -4 HCl g isA- -170 kJ mol -1B- -175 kJ mol -1C- -182-5 kJ mol -1D- -282-5 kJ mol -1

The correct option is C 182.5 kJ mol^ 1For the reaction CCl_4(l) + 2H_2O(g) → CO_2(g) + 4HCl(g),) we have _r H = Enthalpy of reaction _f H= Enthalpy of f ...

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Standard XII

Chemistry

Heat of Formation

The standard ...

Question

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

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

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

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

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

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

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Solution

The correct option is C $- 182.5 k J m o l^{- 1}$
For the reaction $C C l_{4} (l) + 2 H_{2} O (g) \to C O_{2} (g) + 4 H C l (g),)$
we have
$△_{r} H = E n t h a l p y o f r e a c t i o n △_{f} H = E n t h a l p y o f f o r m a t i o n$
$△_{r} H = △_{f} H (C O_{2}, g) + 4 △_{f} H (H C l, g) - △_{F} H (C C l_{4}, l) - 2 △_{f} H (H_{2} O, g)$
Putting all the values, We get;
$△_{r} H = (- 394 - 4 \times 93 + 107 + 2 \times 242) k J m o l^{- 1} = - 175 k J m o l^{- 1}$
Also, We know;
$△ H = △ U + △ n_{g} R T$
where, $△ n_{g}$ is number of change in gaseous moles.
$△ U = △ H - △ n_{g} R T$
$△ n_{g} = 5 - 2 = 3$
putting this and other values in the formula above,
$△ U = △ H - △ n_{g} R T$
$= - 175 k J - (3 \times 8.314 \times 300 \times 10^{- 3} k J) = - 182.5 k J m o l^{- 1}$

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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} (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:

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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Heat of Formation

Standard XII Chemistry

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The standard enthalpies of formation at 300 K for CCl4(l), H2O (g), (CO2) and HCl(g) are −107,−242,−394 and−93 kJ mol−1, respectively. The value of △Uo300 for the reaction CCl4(l)+2H2O(g)→CO2(g)+4HCl(g) is

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

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