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$1$ mole of a gas at $1$ bar and $300 K$ are compressed at constant temperature by use of a constant pressure of $5$ bar. How much work is done on the gas ?

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Important Questions on Chemical Thermodynamics and Energetics

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Tin is obtained from cassiterite by reduction with coke. Use the data given below to determine the minimum temperature (in $K$ ) at which the reduction of cassiterite by coke would take place.

$298 K : Δ_{f} H^{0} ({SnO}_{2} (s)) = - 581.0 kJ {mol}^{- 1}, Δ_{f} H^{0} ({CO}_{2} (g)) = - 394.0 kJ {mol}^{- 1}$

$S^{0} ({SnO}_{2} (s)) = 56.0 {JK}^{- 1} {mol}^{- 1}, S^{0} (Sn (s)) = 52.0 {JK}^{- 1} {mol}^{- 1}$

$S^{0} (C (s)) = 6.0 {JK}^{- 1} {mol}^{- 1}, S^{0} ({CO}_{2} (g)) = 210.0 {JK}^{- 1} {mol}^{- 1}$

Assume that the enthalpies and the entropies are temperature independent.

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The standard heat of formation $(∆_{f} H_{298}^{0})$ of ethane is $- \frac{x}{10} kJ / mol$ , if the heat of combustion of ethane, hydrogen and graphite are $- 1560, - 393.5$ and $- 286 k J / m o l$ , respectively. The value of $x$ to the nearest integer is_____

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

For the reaction:

X_{2} {O_{4}}_{(l)} \to 2 X {O_{2}}_{(g)}

∆ U = 2 .1 kcal, ∆ S = 20 cal K^{- 1}

300 K

Hence,

∆ G

is:

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Enthalpy of fusion and enthalpy of vaporization for water respectively are

6.01 kJ {mol}^{- 1}

and

45.07 kJ {mol}^{- 1}

0 ° C

what is enthalpy of sublimation at

0 ° C

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

For a reaction,

A (g) \to A (l); ΔH = - 3 RT .

The correct statement for the reaction is

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of reaction for

$C_{10} H_{8} (s) + 12 O_{2} (g) ⟶ 10 {CO}_{2} (g) + 4 H_{2} O (l)$ at constant volume is $- 1228.2 kcal$ at $25^{0} C$ . The heat of reaction at constant pressure and same temperature is

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The difference between

∆ H

and

∆ U

(∆ H - ∆ U)

, when the combustion of one mole of heptane

(l)

is carried out at a temperature

T

, is equal to:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The standard enthalpies of formation of ${Al}_{2} O_{3}$ and $CaO$ are $- 1675 kJ {mol}^{- 1}$ and $- 635 kJ {mol}^{- 1}$ respectively.

For the reaction

$3 CaO + 2 Al \to 3 Ca + {Al}_{2} O_{3}$ the standard reaction enthalpy $Δ_{r} H^{0} =$ ________ $kJ .$

(Round off to the Nearest Integer).

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

For complete combustion of ethanol,

C_{2} H_{5} OH (l) + 3 O_{2} (g) \to 2 {CO}_{2} (g) + 3 H_{2} O (l)

,
the amount of heat produced as measured in bomb calorimeter, is

{1364.47 kJ mol}^{-1}

25 ℃

. Assuming ideality the Enthalpy of combustion,

Δ_{c} H

, for the reaction will be:

(R = {8.314 kJ mol}^{-1})

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heats of combustion of carbon and carbon monoxide are

- 393.5 a n d - 283.5 k J m o l^{- 1},

respectively. The heat of formation

(in kJ)

of carbon monoxide per mole is:

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The enthalpies of formation of

{CO}_{(g)}, {CO}_{2 (g)}

and

N_{2} O_{(g)}

are -110,-393 and

81 kJ {mol}^{- 1}

respectively. If the enthalpy of reaction

(Δ_{r} H)

for

N_{2} O_{4 (g)} + 3 {CO}_{(g)} \to N_{2} O_{(g)} + 3 {CO}_{2 (g)}

- 778 kJ,

the enthalpy of formation of

N_{2} O_{4} (g)

{kJmol}^{- 1}

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Given:

C (graphite) + O_{2} (g) \to {CO}_{2} (g); Δ_{r} H^{o} = - 393 .5 kJ {mol}^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ_{r} H^{o} = - 285 .8 kJ {mol}^{- 1}

{CO}_{2} (g) + 2 H_{2} O (l) \to {CH}_{4} (g) + 2 O_{2} (g); Δ_{r} H^{o} = + 890 .3 kJ {mol}^{- 1}

Based on the above thermochemical equations, the value of

Δ_{r} H^{o}

298 K

for the reaction

C (graphite) + 2 H_{2} (g) \to {CH}_{4} (g)

will be:

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

When $0.8 g$ of glucose, $C_{6} H_{12} O_{6}$ , was burnt in a bomb calorimeter, according to the following equation, the temperature raise is found to be $2 K$ at $1 atm$ .

$C_{6} H_{12} O_{6 (s)} + 6 O_{2 (g)} ⟶ 6 {CO}_{2 (g)} + 6 H_{2} O_{(l)}$

If the heat capacity of the bomb calorimeter is $6.8 kJ K^{- 1}$ , the approximate enthalpy change of the reaction in $kJ {mol}^{- 1}$ is (Molar mass of glucose $= 180 g {mol}^{- 1}$ )

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

For the reaction

$N_{2} O_{4} (g) ⟶ 2 {NO}_{2} (g)$

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Standard molar enthalpies of formation of

{CaCo}_{3} (s), Ca ω (s);

and

{Co}_{2} (g)

are

- 1206.92 KJ {mol}^{- 1}, - 635.09 KJ {mol}^{- 1}

and

- 393.51

respectively. The

Δ

Hr for decomposition of

Ca {CO}_{3} (s)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

If the standard molar enthalpy change for combustion of graphite powder is

- 2.48 \times 10^{2} kJ {mol}^{- 1}

, the amount of heat generated on combustion of

1 g

of graphite powder in

kJ

(Nearest integer):

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

298 K

, the enthalpy of fusion of a solid

(X)

2.8 kJ {mol}^{- 1}

and the enthalpy of vaporisation of the liquid

(X)

98.2 kJ {mol}^{- 1}

. The enthalpy of sublimation of the substance

(X)

kJ {mol}^{- 1}

is ______. (in nearest integer)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Enthalpy of sublimation of iodine is

24 c a l g^{- 1}

200 ° C

. If specific heat of

I_{2}

(s) and

I_{2}

(vap) are

0.055

and

0.031 c a l g^{- 1} K^{- 1}

respectively, then enthalpy of sublimation of iodine at

250 ° C

c a l g^{- 1}

is:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The enthalpy change on freezing of

1 mol

of water at

5 ° C

to ice at

- 5 ° C

is:

(Given

Δ_{fus} H = 6 kJ {mol}^{- 1}

0 ° C,

C_{p} (H_{2} O, l) = 75 .3 J {mol}^{- 1} K^{- 1}

C_{p} (H_{2} O, s) = 36 .8 J {mol}^{- 1} K^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The number of endothermic process/es from the following is _______.

A. $I_{2} (g) \to 2 I (g)$

B. $HCl (g) \to H (g) + Cl (g)$

C. $H_{2} O (l) \to H_{2} O (g)$

D. $C (s) + O_{2} (g) \to {CO}_{2} (g)$

E. Dissolution of ammonium chloride in water

1 mole of a gas at 1 bar and 300 K are compressed at constant temperature by use of a constant pressure of 5 bar. How much work is done on the gas ?

Important Questions on Chemical Thermodynamics and Energetics

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$1$ mole of a gas at $1$ bar and $300 K$ are compressed at constant temperature by use of a constant pressure of $5$ bar. How much work is done on the gas ?