Limitations o...

Limitations of First Law

Trending Questions

Q. The heat of formation of

C_{2} H_{5} O H (l)

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

. The heat of combustion of

C H_{3} O C H_{3} (g)

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

△ H_{f}

for

H_{2} O

and

C O_{2}

are

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

and

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

respectively.
Then, the

△ H

for reaction

C_{2} H_{5} O H (l) \to C H_{3} O C H_{3} (g)

is :

$△ H = 18 k c a l m o l^{- 1}$
$△ H = 22 k c a l m o l^{- 1}$
$△ H = 26 k c a l m o l^{- 1}$
$△ H = 30 k c a l m o l^{- 1}$

View Solution

Q. The difference between heat of reactions at constant pressure and constant volume for the reaction

C_{6} H_{6} (l) + \frac{15}{2} O_{2} (g) \to 6 C O_{2} (g) + 3 H_{2} O (l)

25^{\circ} C

in kJ is

-7.43
3.72
-3.72
7.43

View Solution

Q. What will be the amount of heat evolved by burning

10 L

of methane under standard conditions?
(Given heats of formation of

C H_{4}, C O_{2} a n d H_{2} O a r e - 76.2, - 398.8 a n d - 241.6 k J m o l^{- 1}

respectively)

$805.8 k J$
$398.8 k J$
$359.7 k J$
$640.4 k J$

View Solution

Q. The standard enthalpies of formation of

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

and glucose(s) at

25^{o} C

are

- 400 k J / m o l, - 300 ‘ k J / m o l

and

- 1300 k J / m o l,

respectively. The standard enthalpy of combustion per gram of glucose at

25^{o} C

$+ 16.11 k J$
$- 16.11 k J$
$+ 2900 k J$
$- 2900 k J$

View Solution

Q. Ethyl chloride

(C_{2} H_{5} C l)

is prepared by reaction of ethylene with hydrogen chloride:

C_{2} H_{4} (g) + H C l (g) \to C_{2} H_{5} C l (g) Δ H = - 72.3 kJ/mol

What is the value of

Δ E

(in kJ), if

98 g

of ethylene and

109.5 g

H C l

are allowed to react at

300 K

$- 64.81$
$- 190.71$
$- 209.41$
$- 224.38$

View Solution

O_{(g)} + e^{-} \to O_{(g)}^{-} Δ H_{1}

O_{(g)}^{-} + e^{-} \to O_{(g)}^{- 2} Δ H_{2}

O_{2 (g)} \to O_{2 (g)}^{+} + e^{-} Δ H_{3}

O_{(g)} \to O_{(g)}^{+} + e^{-} Δ H_{4}

H_{2 (g)} \to H_{2 (g)}^{+} + e^{-} Δ H_{5}

H_{(g)} \to H_{(g)}^{+} + e^{-} Δ H_{6}

O_{(g)} + 2 e^{-} \to O^{- 2} Δ H_{7}

Which of the following option(s) is/are correct?

$| △ H_{1} | > | △ H_{2} |$
$| △ H_{4} | > | △ H_{3} |$
$| △ H_{5} | > | △ H_{6} |$
$| △ H_{7} |$ is +ve

View Solution

O_{(g)} + e^{-} \to O_{(g)}^{-} Δ H_{1}

O_{(g)}^{-} + e^{-} \to O_{(g)}^{- 2} Δ H_{2}

O_{2 (g)} \to O_{2 (g)}^{+} + e^{-} Δ H_{3}

O_{(g)} \to O_{(g)}^{+} + e^{-} Δ H_{4}

H_{2 (g)} \to H_{2 (g)}^{+} + e^{-} Δ H_{5}

H_{(g)} \to H_{(g)}^{+} + e^{-} Δ H_{6}

O_{(g)} + 2 e^{-} \to O^{- 2} Δ H_{7}

Which of the following option(s) is/are correct?

$| △ H_{1} | > | △ H_{2} |$
$| △ H_{4} | > | △ H_{3} |$
$| △ H_{5} | > | △ H_{6} |$
$| △ H_{7} |$ is +ve

View Solution

Q. The heat of combustion of acetylene is 312 kcal. If heat of formation of

C O_{2}

and

H_{2} O

are 94.38 and 68.38 kcal respectively,

C \equiv \equiv C

bond energy is

x k c a l

. Given that heat of atomisation of C and H are 150.0 and 51.5 kcal respectively and

C - - H

bond energy is 93.64 kcal. Value of

x

161
150
170
None of these

View Solution

Q. The enthpaly combution at

25^{\circ} C of H_{2}

, cyclohexane

(C_{6} H_{12})

and cyclohexene

(C_{6} H_{10})

are

- 241, - 3920

and

- 3800 kJ/mol

respectively. The heat of hydrogenation of cyclohexenes:

$- 121 {kJ mol}^{- 1}$
$+ 121 {kJ mol}^{- 1}$
$- 242 {kJ mol}^{- 1}$
$+ 242 {kJ mol}^{- 1}$

View Solution

Q. The heat of combustion of acetylene is 312 kcal. If heat of formation of

C O_{2}

and

H_{2} O

are 94.38 and 68.38 kcal respectively,

C \equiv \equiv C

bond energy is

x k c a l

. Given that heat of atomisation of C and H are 150.0 and 51.5 kcal respectively and

C - - H

bond energy is 93.64 kcal.

Value of

x

(nearest integer value) is _______.

View Solution

Q. Given,

N H_{3} (g) + 3 C l_{2} (g) \to N C l_{3} (g) + 3 H C l; Δ H_{1}

N_{2} (g) + 3 H_{2} (g) \to 2 N H_{3} (g); Δ H_{2}

H_{2} (g)

C l_{2} (g) \to

2 H C l (g); Δ H_{3}

The heat of formation of

N C l_{3}

in terms of

Δ H_{1}, Δ H_{2} and Δ H_{3}

is:

$Δ H_{1} + \frac{Δ H_{2}}{2} + \frac{3}{2} Δ H_{3}$
$Δ H_{1} - \frac{Δ H_{2}}{2} - \frac{3}{2} Δ H_{3}$
$Δ H_{1} - \frac{Δ H_{2}}{2} + \frac{3}{2} Δ H_{3}$
$Δ H_{1} + \frac{Δ H_{2}}{2} - \frac{3}{2} Δ H_{3}$

View Solution

Q. Given,

C_{2} H_{2} (g) \to C_{2} H_{4} (g) : Δ H^{\circ} = - 175 {kJ mol}^{- 1}

Δ H_{f (C_{2} H_{4}, g)}^{\circ} = 50 kJ mo l^{- 1}; Δ H_{f (H_{2} O, l)}^{\circ} = - 280 {kJ mol}^{- 1}; Δ H_{f (C O_{2} g)}^{\circ} = - 390 {kJ mol}^{- 1}

Δ H^{\circ}

is enthalpy of combustion (in

{kJ mole}^{- 1}

C_{2} H_{2} (g)

, then calculate the value of

∣ ∣ ∣ \frac{Δ H^{\circ}}{257} ∣ ∣ ∣

View Solution

Q. The combustion of benzene

(l)

gives

C O_{2} (g)

and

H_{2} O (l)

. Given that the heat of combustion of benzene at constant volume is —3263.9

k J m o l^{- 1}

25^{\circ} C

. The heat of combustion

(i n k J m o l^{- 1})

of benzene at constant pressure will be:

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

-3267.6
4152.6
-452.46
3260

View Solution

Q. The heats of formaton of

C O_{2} (g)

and

H_{2} O (I)

are -394 kJ/mole and -285.8 kJ/mole respectively. Using the data for the following combustion reaction, calculate the heat of formation of

C_{3} H_{8} (g)

C_{3} H_{8} (g) + 5 O_{2} (g) \to 3 C O_{2} (g) + 4 H_{2} O (l)

;

Δ H_{r x n}^{\circ} = - 2221.6 k J

$+ 212.2$
$- 143.3$
$+ 185.4$
$- 103.6$

View Solution

Q. The heat of reaction for

C_{10} H_{8} (s) + 12 O_{2} (g) \to 10 C O_{2} (g) + 4 H_{2} O (l)

at constant volume is

- 1228.2 Kcal

25^{o} C

. Calculate the heat of reaction at constant pressure and at

25^{o} C

.
(Given :

R = 2 \times 10^{- 3} {Kcal K}^{- 1} {mol}^{- 1}

)

$- 1229.4 Kcal$
$+ 1229.4 Kcal$
$- 1227.0 Kcal$
$+ 1227.0 Kcal$

View Solution

O_{(g)} + e^{-} \to O_{(g)}^{-} Δ H_{1}

O_{(g)}^{-} + e^{-} \to O_{(g)}^{- 2} Δ H_{2}

O_{2 (g)} \to O_{2 (g)}^{+} + e^{-} Δ H_{3}

O_{(g)} \to O_{(g)}^{+} + e^{-} Δ H_{4}

H_{2 (g)} \to H_{2 (g)}^{+} + e^{-} Δ H_{5}

H_{(g)} \to H_{(g)}^{+} + e^{-} Δ H_{6}

O_{(g)} + 2 e^{-} \to O^{- 2} Δ H_{7}

Which of the following option(s) is/are correct?

$| △ H_{1} | > | △ H_{2} |$
$| △ H_{4} | > | △ H_{3} |$
$| △ H_{5} | > | △ H_{6} |$
$| △ H_{7} |$ is +ve

View Solution

Q. Combustion of some amount of ethylene,

6235 kJ

heat was evolved. The heat of combustion of

1

mole of ethylene is

1511 kJ

, What will be the volume of

O_{2}

(at NTP) that entered into the reaction is?

$277.2 mL$
$277.2 litres$
$6226 litres$
$11.2 litres$

View Solution

Q. The formation of the oxide ion

O^{2 -}

involves first an exothermic step followed by an endothermic step as shown below:

O + e^{-} \to O^{-}; Δ H = - 142 k J m o l^{- 1}

O^{-} + e^{-} \to O^{2 -}; Δ H = 844 k J m o l^{- 1}

This is because :

$O^{-}$ ion has comparatively larger size than oxygen atom
oxygen has high electron affinity
$O^{-}$ ion will tend to resist the addition of another electron.
oxygen is more electronegative

View Solution

O_{(g)} + e^{-} \to O_{(g)}^{-} Δ H_{1}

O_{(g)}^{-} + e^{-} \to O_{(g)}^{- 2} Δ H_{2}

O_{2 (g)} \to O_{2 (g)}^{+} + e^{-} Δ H_{3}

O_{(g)} \to O_{(g)}^{+} + e^{-} Δ H_{4}

H_{2 (g)} \to H_{2 (g)}^{+} + e^{-} Δ H_{5}

H_{(g)} \to H_{(g)}^{+} + e^{-} Δ H_{6}

O_{(g)} + 2 e^{-} \to O^{- 2} Δ H_{7}

Which of the following option(s) is/are correct?

$| △ H_{1} | > | △ H_{2} |$
$| △ H_{4} | > | △ H_{3} |$
$| △ H_{5} | > | △ H_{6} |$
$| △ H_{7} |$ is +ve

View Solution

Q. The heat of formation of

C_{2} H_{5} O H (l)

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

. The heat of combustion of

C H_{3} O C H_{3} (g)

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

△ H_{f}

for

H_{2} O

and

C O_{2}

are

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

and

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

respectively.
Then, the

△ H

for reaction

C_{2} H_{5} O H (l) \to C H_{3} O C H_{3} (g)

is :

$△ H = 18 k c a l m o l^{- 1}$
$△ H = 22 k c a l m o l^{- 1}$
$△ H = 26 k c a l m o l^{- 1}$
$△ H = 30 k c a l m o l^{- 1}$

View Solution

O_{(g)} + e^{-} \to O_{(g)}^{-} Δ H_{1}

O_{(g)}^{-} + e^{-} \to O_{(g)}^{- 2} Δ H_{2}

O_{2 (g)} \to O_{2 (g)}^{+} + e^{-} Δ H_{3}

O_{(g)} \to O_{(g)}^{+} + e^{-} Δ H_{4}

H_{2 (g)} \to H_{2 (g)}^{+} + e^{-} Δ H_{5}

H_{(g)} \to H_{(g)}^{+} + e^{-} Δ H_{6}

O_{(g)} + 2 e^{-} \to O^{- 2} Δ H_{7}

Which of the following option(s) is/are correct?

$| △ H_{1} | > | △ H_{2} |$
$| △ H_{4} | > | △ H_{3} |$
$| △ H_{5} | > | △ H_{6} |$
$| △ H_{7} |$ is +ve

View Solution

Q. The formation of the oxide ion

O^{2 -} (g)

requires first an exothermic and then an endothermic step as shown below.

O_{(g)} + e^{-} = O^{-} (g), Δ H^{0} = - 142 k J m o l^{- 1}

O^{-} (g) + e^{-} = O^{2 -} (g), Δ H^{0} = + 844 k J m o l^{- 1}

This is because :

$O^{-}$ ion will tend to resist the addition of another electron
oxygen has high electron affinity
$O^{-}$ ion has comparatively larger size than oxygen atom
oxygen is more electronegative

View Solution

Q. The heat of formation of

C_{2} H_{5} O H (l)

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

. The heat of combustion of

C H_{3} O C H_{3} (g)

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

△ H_{f}

for

H_{2} O

and

C O_{2}

are

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

and

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

respectively.
Then, the

△ H

for reaction

C_{2} H_{5} O H (l) \to C H_{3} O C H_{3} (g)

is :

$△ H = 18 k c a l m o l^{- 1}$
$△ H = 22 k c a l m o l^{- 1}$
$△ H = 26 k c a l m o l^{- 1}$
$△ H = 30 k c a l m o l^{- 1}$

View Solution

Q. The heat of formation of

C_{2} H_{5} O H (l)

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

. The heat of combustion of

C H_{3} O C H_{3} (g)

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

△ H_{f}

for

H_{2} O

and

C O_{2}

are

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

and

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

respectively.
Then, the

△ H

for reaction

C_{2} H_{5} O H (l) \to C H_{3} O C H_{3} (g)

is :

$△ H = 18 k c a l m o l^{- 1}$
$△ H = 22 k c a l m o l^{- 1}$
$△ H = 26 k c a l m o l^{- 1}$
$△ H = 30 k c a l m o l^{- 1}$

View Solution