Thermodynamics practice · Easy

Heat of formation of compound is defined as :

Which of the following gas will liberate maximum heat on combustion per gram?

Which of the following is an intensive property?

Statement-I (S-I): Absolute values of internal energy cannot be determined

Statement-II (S-II): It is impossible to determine the exact values of constituent energies of the substances.

The enthalpy of neutralization of a substance

Unit of entropy is

ASSERTION (A) : For the combustion of methane, $\Delta U>\Delta H$

REASON (R): $\Delta H$ is related by $\Delta U$ by the expression $\Delta H=\Delta U+\Delta n R T$

When water is added to quick lime, the reaction is :

Given below are two statements one is labelled as Assertion (A) and the other is labelled as Reason (R)

Assertion (A): Heat of neutralisation of $HF$ (aq.) with ${NaOH}$ (aq.) is greater than $13.7 \mathrm{~Kcal}$.

Reason (R): Generally some heat is consumed in the ionisation of weak acid.
On the basis of above statements choose the most appropriate option from the following options:

A boiled egg show a/an …in entropy.

The total heat content of a system at constant pressure is

Assertion : Born-Haber cycle is based on Hess's law.

Reason : Lattice enthalpy can be calculated by Born Haber cycle.

$\begin{aligned} & \Delta H_f^{\circ}\left(\mathrm{NO}_2\right)=33.84 \mathrm{~kJ} \mathrm{~mol}^{-1} \\ & \Delta H_f^{\circ}\left(\mathrm{N}_2 \mathrm{O}_4\right)=9.66 \mathrm{~kJ} \mathrm{~mol}^{-1} \end{aligned}$

hence, dimerisation of $\mathrm{NO}_2$ forming $\mathrm{N}_2 \mathrm{O}_4$ is

The work done by a weightless piston in causing an expansion ∆V (at constant temperature), when the opposing pressure, P is variable, is given by:

For which of the following elements, the standard enthalpy is not zero.

Assertion (A): Heat of neutralisation is always less than zero.

Reason (R): Neutralisation involves reaction between an acid and a base.

${Na}(\mathrm{s}) \rightarrow {Na}(\mathrm{g})$, the heat of reaction is called as

The heat of neutralisation for strong acid and strong base forming 2 moles of water is

The law of Lavoisier and Laplace is based on :

The gas in a refrigerator causes cooling on expansion because:

Energy equivalent to one erg, one joule and one calorie are in order:

The enthalpies of elements under the following conditions are assumed to be

For the dissociation reaction, $\mathrm{H}_2(\mathrm{~g}) \rightarrow 2 \mathrm{H}(\mathrm{g}), \Delta \mathrm{H}=162 \mathrm{Kcal}$, heat of atomization of $\mathrm{H}$ is

A mixture of two moles of carbon monoxide and one mole of oxygen, in a closed vessel is ignited to convert the carbon monoxide to carbon dioxide. If ∆H is the enthalpy change and ∆E is the change in internal energy, then

Which is an extensive property of the system?

Which is the correct Gibb's Helmholtz
equation?

Consider the following thermochemical equation $2 \mathrm{H}_2(\mathrm{g})+\mathrm{O}_2(\mathrm{g}) \rightarrow 2 \mathrm{H}_2 \mathrm{O}(\mathrm{g}) \, \Delta \mathrm{H}^{\circ}=-470 \mathrm{~kJ}$ If standard enthalpy of vaporisation of $\mathrm{H}_2 \mathrm{O}(\ell)$ is $50 \mathrm{~kJ} / \mathrm{mole}$, then find calorific value of $\mathrm{H}_2(\mathrm{g})$ in standard conditions:

STATEMENT-1 : There cannot be chemical equilibrium in an open system.

STATEMENT-2 : There is no fixed mass in an open system.

STATEMENT-1: The expansion of a gas into an evacuated space takes place non-spontaneously.

STATEMENT-2 : A process in which all steps cannot be retraced by themselves is called a spontaneous process.

Taking each reactant in 1:1 molar ratio, enthalpy changes are $\Delta H_1^\circ$ and $\Delta H_2^\circ$ in the following reactions.

$\begin{aligned} & \mathrm{Ca}(\mathrm{OH})_2+\mathrm{HCl} \longrightarrow \mathrm{Ca}(\mathrm{OH}) \mathrm{Cl}+\mathrm{H}_2 \mathrm{O} ; \Delta \mathrm{H}_1{ }^{\circ} \\ & \mathrm{Ca}(\mathrm{OH}) \mathrm{Cl}+\mathrm{HCl} \longrightarrow \mathrm{CaCl}_2+\mathrm{H}_2 \mathrm{O} ; \Delta \mathrm{H}_2{ }^{\circ} \end{aligned}$

$\Delta H_{1^{\circ}}$ and $\Delta H_{2^{\circ}}$ are (in kcal)