Thermodynamics · Chemistry · AP EAPCET

Consider the following.

Statement -I Both internal energy $(U)$ and work $(W)$ are state functions.

Statement-II During the free expansion of an ideal gas into vacuum, the work done is zero.

The correct answer is

The signs of $\Delta_r H^{\circ}$ and $\Delta_r S^{\circ}$ for a reaction to be spontaneous at all temperature respectively are

5 moles of a gas is allowed to pass through a series of changes as shown in the graph, in a cyclic process. The processes $C \rightarrow A, B \rightarrow C$ and $A \rightarrow B$ respectively are

1 mole of an ideal gas is allowed to expand isothermally and reversibly from $\mathrm{1L}$ to 5 L at 300 K . The change in enthalpy (in kJ ) is $\left(R=8.3 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$

The number of extensive and intensive properties in the list given below is respectively, density, enthalpy, mass, temperature, volume, pressure

One mole of ethanol ( $l$ ) was completely burnt in oxygen to form $\mathrm{CO}_2(\mathrm{~g})$ and $\mathrm{H}_2 \mathrm{O}(l)$. What is the $\Delta_r H^{\circ}$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for this reaction?

(The standard enthalpy of formation $\left(\Delta_f H^{\circ}\right)$ of $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}(l), \mathrm{CO}_2(g)$ and $\mathrm{H}_2 \mathrm{O}(l)$ is respectively $-277,-393$ and $-286 \mathrm{~kJ} \mathrm{~mol}^{-1}$ )

If $\Delta_r H^{\ominus}$ and $\Delta_r S^{\ominus}$ are standard enthalpy change and standard entropy change respectively for a reaction, the incorrect option is

The $\mathrm{C}_p$ of $\mathrm{H}_2 \mathrm{O}(l)$ is $75.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$. What is the energy (in J ) required to raise 180 g of liquid water from $10^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$ ? $\left(\mathrm{H}_2 \mathrm{O}=18 \mathrm{u}\right)$

Identify the incorrect statements from the following.

I. For adiabatic process, $\Delta U=w_{\text {ad }}$

II. Enthalpy is an intensive property

III. For the process, $\mathrm{H}_2 \mathrm{O}(l) \rightarrow \mathrm{H}_2 \mathrm{O}(s)$, the entropy increases

The correct answer is

Enthalpy of formation of $\mathrm{CO}_2(\mathrm{~g}), \mathrm{H}_2 \mathrm{O}(\mathrm{l})$ and $\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6(\mathrm{~s})$ are $-393,-286$ and $-1170 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The quantity of heat liberated when 18 g of $\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6(s)$ is burnt completely in oxygen is

For which reaction $\Delta H \neq \Delta U ?$

At $298 \mathrm{~K}, \Delta_r U^{\ominus}$ and $\Delta_r S^{\ominus}$ for the following reaction are -10.5 kJ and $+44.1 \mathrm{JK}^{-1} ; 2 X(\mathrm{~g})+Y(\mathrm{~g}) \longrightarrow 2 Z(\mathrm{~g})$ What is $\Delta_r G^{\ominus}$ (in kJ ) for this reaction? $\left(R=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$

Consider the following reaction

$$ A(g)+3 B(g) \longrightarrow 2 C(g) ; \Delta H^{\ominus}=-24 \mathrm{~kJ} $$

At $25^{\circ} \mathrm{C}$, if $\Delta G^{\ominus}$ of the reaction is -9 kJ , the standard entropy change (in $\mathrm{JK}^{-1}$ ) of the same reaction at same temperature is

One mole of $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}(l)$ was completely burnt in oxygen to form $\mathrm{CO}_2(g)$ and $\mathrm{H}_2 \mathrm{O}(l)$. The standard enthalpy of formation $\left(\Delta_f H^{\ominus}\right)$ of $\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}(l), \mathrm{CO}_2(g)$ and $\mathrm{H}_2 \mathrm{O}(l)$ is $x, y$, $z \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. What is $\Delta_r H^{\ominus}\left(\right.$ in $\left.\mathrm{kJ} \mathrm{mol}^{-1}\right)$ for this reaction?

Identify the correct statements from the following.

I. Work is a path function.

II. Enthalpy is an extensive property.

III. Lattice enthalpy of ionic compounds can be obtained from Born-Haber cycle.

Which of the following processes entropy change $(\Delta S)$ is negative?

I. Sublimation of dry ice

II. Freezing of water

III. Crystallisation of the dissolved substance

IV. Burning of rocket fuel

Consider the following :

Statement I : During isothermal expansion of an ideal gas its enthalpy decreases.

Statement II : When 2.0 L of an ideal gas expands isothermally into vaccum, $\Delta U=0$.

The correct answer is :

The energy required to increase the temperature of 180 g of liquid water from $10^{\circ} \mathrm{C}$ to $15^{\circ} \mathrm{C}$ is 3765 J . What is $C_p$ of water in $\mathrm{J} \mathrm{mol}^{-1} \mathrm{~K}^{-1} ?\left(\mathrm{H}_2 \mathrm{O}=18 \mathrm{u}\right)$

At 273 K the maximum work done when pressure on 10 g of hydrogen is reduced from 10 atm to 1 atm under isothermal, reversible conditions is

(Assume the gas behaves ideally)

$$ \left(R=83 \mathrm{Jk}^{-1} \mathrm{~mol}^{-1}\right) $$

Observe the following reaction.

$$ A B \mathrm{O}_3(\mathrm{~s}) \xrightarrow{1000 \mathrm{~K}} A \mathrm{O}(\mathrm{~s})+B \mathrm{O}_2(\mathrm{~g}) $$

$\Delta_r H$ for this reaction is $x \mathrm{~kJ} \mathrm{~mol}^{-1}$. What is its $\Delta_r U$ (in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) at the same temperature?

$$ \left(R=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right) $$

At $300 \mathrm{~K}, \Delta_r G^{\Theta}$ for the reaction $A_2(g) \rightleftharpoons B_2(g)$ is $-11.5 \mathrm{~kJ} \mathrm{~mol}^{-1}$. The Equilibrium constant at 300 K is approximately ( $R=8314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}$ )

Two statements are given below.

Statement I : The reaction $\mathrm{Cr}_2 \mathrm{O}_3+2 \mathrm{Al} \longrightarrow \mathrm{Al}_2 \mathrm{O}_3+2 \mathrm{Cr}$ $\left(\Delta G^{\ominus}=-421 \mathrm{~kJ}\right)$ is thermodynamically feasible.

Statement II : The above reaction occurs at room temperature.

The correct answer is

What is the enthalpy change (in J ) for converting 98 of $\mathrm{H}_2 \mathrm{O}(t)+10^{\circ} \mathrm{C}$ to $\mathrm{H}_2 \mathrm{O}(l)$ at $+20^{\circ} \mathrm{C}$ ?

$$ \left(C_p\left(\mathrm{H}_2 \mathrm{O}(\eta)\right)=75 \mathrm{Jmol}^{-1} \mathrm{~K}^{-1}\right) $$

(density of $\mathrm{H}_2 \mathrm{O}(l)=1 \mathrm{gmL}^{-1}{ }^{})$

$A, B, C$ and $D$ are some compounds. The entnalpy of formation of $A(g), B(g), C(g)$ and $D(g)$ is $9.7,-110,81$ and $-393 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. What is $\Delta_r H$

(in $\mathrm{kJ} \mathrm{mol}^{-1}$ ) for the given reaction ?

$$ A(g)+3 B(g) \longrightarrow C(g)+3 D(g) $$

Observe the following reactions.

$$ \begin{array}{ll} A B(g)+25 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow\left(25 \mathrm{H}_2 \mathrm{O}\right) A B ; & \Delta H=x \mathrm{~kJ} \mathrm{~mol}^{-1} \\ A B(g)+50 \mathrm{H}_2 \mathrm{O}(l) \longrightarrow\left(50 \mathrm{H}_2 \mathrm{O}\right) A B ; & \Delta H=y \mathrm{~kJ} \mathrm{~mol}^{-1} \end{array} $$

Observe the following reaction,

$$ 2 A_2(g)+B_2(g) \xrightarrow{T(\mathrm{~K})} 2 A_2 B(g)+600 \mathrm{~kJ} $$

The standard enthalpy of formation $\left(\Delta_f H^{\ominus}\right)$ of $A_2 B(g)$ is

Given below are two statements :

Statement I For isothermal irreversible change of an ideal gas, $q=-w=p_{\text {ext }}\left(V_{\text {final }}-V_{\text {initial }}\right)$

Statement II For adiabatic change, $\Delta U=w_{\text {adiabatic }}$

The correct answer is :

Identify the incorrect statements form the following.

I. $ \Delta S_{\text {pum }}=\left(\Delta S_{\text {nal }}+\Delta S_{\text {um }}\right) $

II. $A(\bar{i} \rightarrow A(\phi)$ : For this process entropy change decreases.

III. Entropy units are $\mathrm{JK} \mathrm{mol}^{-1}$.

Identify the correct statements from the following.

I. At 0 K , the entropy of pure crystalline materials approach zero.

II. Entropy for the process, $$\mathrm{H}_2 \mathrm{O}(\mathrm{l}) \longrightarrow \mathrm{H}_2 \mathrm{O}(\mathrm{g})$$ decreases.

III. Gibb's energy is a state function.

Use the data from table to estimate the enthalpy of formation of $$\mathrm{CH}_3 \mathrm{CHO}$$.

From the following plots, find the correct option.

Observe the following properties : Volume, enthalpy, density, temperature, heat capacity, pressure and internal energy. The number of extensive properties in the above list is

Match the following.

Which of the following expression is correct?

Identify the reaction/process in which the entropy increases.

State $$1 \rightleftharpoons$$ State $$2 \rightleftharpoons$$ State 3 $$\left(\begin{array}{l}T=300 \mathrm{~K} \\ p=15 \mathrm{bar} \\ 1 \mathrm{~mol}\end{array}\right)\left(\begin{array}{l}T=300 \mathrm{~K} \\ p=10 \mathrm{bar} \\ 1 \mathrm{~mol}\end{array}\right)\left(\begin{array}{l}T=300 \mathrm{~K} \\ p=5 \mathrm{bar} \\ 1 \mathrm{~mol}\end{array}\right)$$

Above shows a cyclic process. Calculate the total work done during one complete cycle. [Assume a single step to reach the next state].

When an ideal gas expands isothermally from $$5 \mathrm{~m}^3$$ to $$10 \mathrm{~m}^3$$ at $$25^{\circ} \mathrm{C}$$ against a constant pressure of $$10^7 \mathrm{~Nm}^{-2}$$, then the work done on the gas is

Find the approximate value of $$(\Delta H-\Delta U)$$ in $$\mathrm{Jmol}^{-1}$$, for the formation of CO from its elements at $$298 \mathrm{~K} .\left(R=8.314 \mathrm{JK}^{-1} \mathrm{~mol}^{-1}\right)$$

For the reaction, $$\mathrm{H}_2 \mathrm{O}(l) \longrightarrow \mathrm{H}_2 \mathrm{O}(\mathrm{g})$$ at $$T=100^{\circ} \mathrm{C}$$ and $$p=1 \mathrm{~atm}$$, choose the correct option.

Two flasks $$A$$ and $$B$$ have equal volumes. $$A$$ is maintained at $$300 \mathrm{~K}$$ and $$B$$ at $$600 \mathrm{~K}$$. Equal masses of $$\mathrm{H}_2$$ and $$\mathrm{CO}_2$$ are taken in flasks $$A$$ and $$B$$ respectively. Find the ratio of total KE of gases in flask $$A$$ to that of $$B$$.

When the temperature of 2 moles of an ideal gas is increased by 20$$^\circ$$C at constant pressure. Find the work involved in the process.

If a chemical reaction is known to be non-spontaneous at 298 K but spontaneous at 350 K, then which among the following conditions is true for the reaction?