EASY

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Calculate the amount of heat evolved when $500 c m^{3}$ of 0.1 M HCl is mixed with $200 c m^{3}$ of 0.2 M NaOH.

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Important Questions on Chemical Thermodynamics and Energetics

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Identify the INVALID equation.

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

When

600 mL

0.2 M {HNO}_{3}

is mixed with

400 mL

0.1 M NaOH

solution in a flask, the rise in temperature of the flask is_____

\times 10^{- 2} ° C

(Enthalpy of neutralisation

= 57 kJ {mol}^{- 1}

and Specific heat of water

= 4.2 {JK}^{- 1} g^{- 1}

) (Neglect heat capacity of flask)

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of atomization of methane and ethane are

360 kJ {mol}^{- 1}

and

620 kJ {mol}^{- 1}

, respectively. The longest wavelength of light capable of breaking the

C - C

bond is (Avogadro's number

= 6.023 \times 10^{23}, h = 6.62 \times 10^{- 34} J s

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The combustion of benzene

(l)

gives

{CO}_{2} (g)

and

H_{2} O (l) .

Given that heat of combustion of benzene at constant volume is

- 3263 .9 kJ {mol}^{- 1}

25 ° C;

the heat of combustion

(in kJ {mol}^{- 1})

of benzene at constant pressure will be

(R = 8 .314 {JK}^{- 1} {mol}^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of neutralization of the following reaction is $- 57.1 kJ {mol}^{- 1}$ .

$NaOH (aq) + HCl (aq) \to NaCl (aq) + H_{2} O (l)$

Which one of the following processes is mainly responsible for the heat released?

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}

)

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of combustion of carbon to

C O_{2}

- 393.5 kJ / mol

. The heat released upon the formation of

35.2 g

C O_{2}

from carbon and oxygen gas is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Lattice enthalpy and enthalpy of solution of

NaCl

are

788 {kJmol}^{- 1}

and

4 k J m o l^{- 1}

, respectively. The hydration enthalpy of

N a C l

is:

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Equal volume of

1 M HCl

and

1 M H_{2} {SO}_{4}

are neutralised by dil.

NaOH

solution separately. If

X Kcal

and

Y Kcal

of heat are liberated respectively, then which of the following relation is correct?

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of neutralisation of hydrogen cyanide

(HCN)

- 2 .9 kcal {mol}^{- 1}

. This shows that heat of dissociation of

HCN

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:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

When $400 mL$ of $0.2 M H_{2} {SO}_{4}$ solution is mixed with $600 mL$ of $0.1 MNaOH$ solution, the increase in temperature of the final solution is $— \times 10^{- 2} K$ . (Round off to the nearest integer).

[Use : $H^{+} (aq) + {OH}^{-} (aq) \to H_{2} O :$ $Δ_{γ} H = - 57.1 kJ {mol}^{- 1}]$

Specific heat of $H_{2} O = 4.18 J K^{- 1} g^{- 1}$ , density of $H_{2} O = 1.0 g {cm}^{- 3}$

Assume no change in volume of solution on mixing.

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:

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The standard enthalpies of formation of ${CO}_{2} (g)$ $, H_{2} O (l)$ and glucose (s) at $2 5^{o} C$ are $- 400 kJ / mol$ , $- 300 kJ / mol$ and $- 1300 kJ / mol$ , respectively. The standard enthalpy combustion per gram of glucose at $2 5^{o} C$ is

( ${ΔH}_{f}^{0} = - 1300 kJ {mol}^{- 1}$ for Glucose)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

If enthalpy of atomization for

B r_{2} (l)

x k J / m o l

and bond enthalpy for

B r_{2}

y k J / m o l

, the relation between them

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

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

Enthalpy of combustion of methane and ethane are

- 210 k cal / mol

and

- 368 k cal / mol

respectively. The enthalpy of combustion of decane is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

While performing a thermodynamics experiment, a student made the following observations, $HCl + NaOH \to NaCl + H_{2} O Δ H = - 57.3 kJ {mol}^{- 1}$

${CH}_{3} COOH + NaOH \to {CH}_{3} COONa + H_{2} O$

$ΔH = - 55.3 kJ {mol}^{- 1}$ .

The enthalpy of ionization of ${CH}_{3} COOH$ as calculated by the student is $kJ {mol}^{- 1}$ .

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

The heat of neutralisation will be highest in

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics and Energetics>Enthalpy

When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a temperature increase of

{5.7}^{o} C

was measured for the beaker and its contents (Expt.1). Because the enthalpy of neutralization of a strong acid with a strong base is a constant

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

, this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. 2), 100 mL of 2.0 M acetic acid

(K_{a} = 2.0 \times 10^{- 5})

was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of

{5.6}^{o} C

was measured. (Consider heat capacity of all solutions as

4.2 J g^{- 1} K^{- 1}

and density of all solutions as

1.0 g m L^{- 1}

)

Enthalpy of dissociation

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

of acetic acid obtained from the Expt. 2 is

Calculate the amount of heat evolved when 500 cm3 of 0.1 M HCl is mixed with 200 cm3 of 0.2 M NaOH.

Important Questions on Chemical Thermodynamics and Energetics

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Calculate the amount of heat evolved when $500 c m^{3}$ of 0.1 M HCl is mixed with $200 c m^{3}$ of 0.2 M NaOH.