Thermodynamics · Chemistry · COMEDK

For an ideal gas undergoing an isothermal change, there is $\_\_\_\_$

The standard enthalpies of formation of $\mathrm{CH}_4(\mathrm{~g}), \mathrm{CO}_2(\mathrm{~g})$ and $\mathrm{H}_2 \mathrm{O}(\mathrm{l})$ are $-74.8 \mathrm{~kJ} \mathrm{~mol}^{-1},-393.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $-285.8 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. Then the enthalpy change for the given reaction in $\mathrm{kJ} \mathrm{mol}^{-1}$ will be:

$$ 2 \mathrm{CH}_4(\mathrm{~g})+4 \mathrm{O}_2(\mathrm{~g}) \rightarrow 2 \mathrm{CO}_2(\mathrm{~g})+4 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) $$

Identify the INCORRECT statement

Ozone is formed by the reaction

$$ \mathrm{O}_{2(g)}+\mathrm{O}_{(g)} \rightarrow \mathrm{O}_{3(g)}, \Delta \mathrm{H}=-107.2 \mathrm{~kJ} . $$

Given $\mathrm{O}=0$ bond energy is $498.0 \mathrm{~kJ} \mathrm{~mol}^{-1}$, the average bond energy of ozone is:

$\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ for a reaction are $35.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $83.6 \mathrm{~J} \mathrm{~K}^{-1}$ respectively. Assuming that $\Delta \mathrm{H}$ and $\Delta \mathrm{S}$ do not vary with temperature, the reaction is spontaneous when:

The heat of combustion of carbon to $\mathrm{CO}_2$ is $-393.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$.

The heat released on the formation of 35.2 g of $\mathrm{CO}_2$ by combustion of C is:

The Enthalpy of combustion of $$\mathrm{C}_6 \mathrm{H}_5 \mathrm{COOH}(\mathrm{s})$$ at $$25^{\circ} \mathrm{c}$$ and 1.0 atm pressure is $$-2546 \mathrm{~kJ} / \mathrm{mol}$$. What is the Internal energy change for this reaction?

Given :

$$ \begin{gathered} \Delta \mathrm{H}^0 \mathrm{f}_{\text {of }} \mathrm{CO}_2(\mathrm{~g})=-393.5 \mathrm{~kJ} / \mathrm{mol} \\ \Delta \mathrm{H}^0{ }_{\mathrm{f}} \text { of } \mathrm{H}_2 \mathrm{O}(\mathrm{l})=-286 \mathrm{~kJ} / \mathrm{mol} \\ \Delta \mathrm{H}^0{ }_{\mathrm{f}} \text { of } \mathrm{C}_3 \mathrm{H}_6(\mathrm{~g})=+20.6 \mathrm{~kJ} / \mathrm{mol} \end{gathered} $$

$$\Delta \mathrm{H}^0$$ isomerisation of Cyclopropane to Propene $$=-33 \mathrm{~kJ} / \mathrm{mol}$$

What is the standard enthalpy of combustion of Cyclopropane?

5.0 moles of an Ideal gas at 3.0 atm pressure and $$27^{\circ} \mathrm{C}$$ is compressed isothermally to half its volume by application of an external pressure of $$3.5 \mathrm{~atm}$$. What is the amount of work done (in joules) on the gas? Given: $$1 \mathrm{~L} \mathrm{~atm}=101.3 \mathrm{~J}: \mathrm{R}=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~K}{ }^{-1} \mathrm{~mol}^{-1}$$

The $$\Delta \mathrm{H}_{(\mathrm{f})}^{\mathrm{o}}$$ of $$\mathrm{NO}_2(\mathrm{~g})$$ and $$\mathrm{N}_2 \mathrm{O}_4(\mathrm{~g})$$ are 16.0 and $$4.0 \mathrm{k} \mathrm{cal} \mathrm{mol}^{-1}$$ respectively. The heat of dimerisation of $$\mathrm{NO}_2$$ in $$\mathrm{k}$$ cal is :

At Constant volume, the heat required to raise the temperature of $$4.48 \mathrm{~L}$$ of an ideal gas at STP by $$15^{\circ} \mathrm{C}$$ is 12.0 calories. The $$\mathrm{C_p}$$ of the gas is _____________ $$(\mathrm{R}=2 \mathrm{~Cal} \mathrm{~kg}^{-1} \mathrm{~mol}^{-1})$$

The correct option for free expansion of an ideal gas under adiabatic condition is:

The standard enthalpy of formation of $$\mathrm{CH}_4$$, the standard enthalpy of sublimation of Carbon and the bond dissociation enthalpy of Hydrogen gas are $$-74.8,+719.6$$ and $$436 \mathrm{~kJ} / \mathrm{mol}$$ respectively. What is the bond enthalpy of $$\mathrm{C}-\mathrm{H}$$ bond in Methane?

Given: $$\Delta \mathrm{G}^0{ }_{\mathrm{f}}$$ of $$\mathrm{C}_2 \mathrm{H}_2$$ is $$2.09 \times 10^5 \mathrm{~J} / \mathrm{mol}$$ and $$\Delta \mathrm{G}_{\mathrm{f}}^0$$ of $$\mathrm{C}_6 \mathrm{H}_6$$ is $$1.24 \times 10^5 \mathrm{~J} / \mathrm{mol}$$. Calculate the equilibrium constant for the cyclic polymerisation of Ethyne to Benzene at $$27^{\circ} \mathrm{C}$$. $$(\mathrm{R}=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1})$$

If the enthalpy of formation of a diatomic molecule $$\mathrm{AB}$$ is $$-400 \mathrm{~kJ} / \mathrm{mol}$$ and the bond dissociation energies of $$\mathrm{A}_2$$ and $$\mathrm{B}_2$$ and $$\mathrm{AB}$$ are in the ratio $$2: 1: 2$$, what is the bond dissociation enthalpy of $$\mathrm{B}_2$$ ?

If 2 moles of $$\mathrm{C}_6 \mathrm{H}_6(\mathrm{~g})$$ are completely burnt $$4100 \mathrm{~kJ}$$ of heat is liberated. If $$\Delta H^{\circ}$$ for $$\mathrm{CO}_2(\mathrm{~g})$$ and $$\mathrm{H}_2 \mathrm{O}(l)$$ are $$-410$$ and $$-285 \mathrm{~kJ}$$ per mole respectively then the heat of formation of $$\mathrm{C}_2 \mathrm{H}_6(g)$$ is

For an adiabatic change in a system, the condition which is applicable is

$$5.8 \mathrm{~g}$$ of a gas maintained at $$95^{\circ} \mathrm{C}$$ occupies the same volume as $$0.368 \mathrm{~g}$$ of hydrogen gas maintained at a temperature of $$17^{\circ} \mathrm{C}$$ and pressure being the same atmospheric pressure for both the gases. What is the molecular mass of the unknown gas?

Gaseous Nitrous oxide decomposes at $$298 \mathrm{~K}$$ to form Nitrogen gas and Oxygen gas. The $$\Delta \mathbf{H}$$ for the reaction at $$1.0 \mathrm{~atm}$$ pressure and $$298 \mathrm{~K}$$ is $$\mathbf{- 1 6 3 . 1 5} \mathbf{~ k J}$$. Calculate Internal energy change for the decomposition of $$100 \mathrm{~g}$$ of Nitrous oxide gas under the same conditions of temperature and pressure.

A Gas taken in a closed vessel is heated from $$54^{\circ} \mathrm{C}$$ to $$1254^{\circ} \mathrm{C}$$. The pressure of the gas becomes ___________ times its original pressure $$\mathrm{P_1}$$

Which of the following are not path functions?

I. H $$-$$ TS

II. W

III. q

IV. q + W

The relation between work done in reversible and irreversible process is

In which of the following changes, entropy decreases?

The difference between heat capacity at constant pressure and heat capacity at constant volume is

When the expansion of a gas occurs in vacuum and at constant volume, then

The change in the energy of system if 500 cal of heat energy are added to a system and system does 350 cal of work on the surroundings will be

Calculate the difference between C$$_p$$ and C$$_V$$ for 10 moles of an ideal gas

The value of $$\Delta G^\circ$$ for the phosphorylation of glucose in glycolysis is 13.8 kJ/mol. The value of $$K_C$$ at 298 K is

Which of the following is an intensive property?

Thermodynamic standard conditions of temperature and pressure are

In which of the following process, a maximum increase in entropy is observed?

Consider the reaction,

C(s) + O$$_2$$(g) $$\rightarrow$$ CO$$_2$$(g) + 393.5 kJ

The signs of $$\Delta H,\Delta S$$ and $$\Delta G$$ respectively are

Entropy of the universe is