Gibbs Free Energy & Spontaneity

Q. Why work done in a reversible is greater than Irreversible during compression and vice versa is true for work done during expansion???
​​

Q.

The equilibrium constant for a reaction is 10. What will be the value of $\Delta G^{\theta }$? $R=8.314J{K}^{-1}mo{l}^{-1}T=300K$.

Q. mole fraction of oxygen in mixture of 7g of nitrogen and 8 g of oxygen

Q.

A reaction, A + B $\to$ C + D + q is found to have a positive entropy change. The reaction will be
(i) possible at high temperature
(ii) possible only at low temperature
(iii) not possible at any temperature
(iv) possible at any temperature

Q.

For the reaction
$2A_{\left(g\right)}+B_{\left(g\right)}\to 2D_{\left(g\right)}\Delta U^{\theta }=-10.5kJand\Delta S^{\theta }=–44.1J{K}^{-1}$.
Calculate $\Delta G^{\theta }$ for the reaction, and predict whether the reaction may occur spontaneously.

Q.

Count Function in SQL Returns the Number of

1. values

2. distinct Values

3. Groups

4. Columns.

Q. For a given reaction, $\Delta H=35.5kJmo{l}^{-1}and\Delta S=83.6J{K}^{-1}mo{l}^{-1}$. The reaction is spontaneous at (Assume that $\Delta Hand\Delta S$ do not vary with temperature.)

1. T > 425 K
2. All temperatures
3. T < 425 K
4. T > 298 K

Q. 39. A catalyst lowers the activation energy of a reaction from 20 kJ per mole to 10 kJ per mole. The temperature at which an catalyzed reaction will have same rate as that of catalyzed at 27 degree Celsius

Q. Which of the following relations is/are correct?

1. $\Delta G=\Delta H-T\Delta S$
2. $\Delta G=\Delta H+T{\left[\frac{\delta \left(\Delta G\right)}{\delta T}\right]}_P$
3. $\Delta G=\Delta H+T\Delta S$
4. $\Delta G=\Delta H+\Delta nRT$

Q. Calculate the boiling point of bromine from the following data: $△H^{o}and△S^o$ values of $B{r}_2\left(l\right)\to B{r}_2\left(g\right)$ are 30.91 $kJ/mol$ and 93.2 $Jmo{l}^{-1}{K}^{-1}$ respectively. (Assume that $△Hand△S$ do not vary with temperature.)

Q. The value of $lo{g}_{10}$K for a reaction $A\rightleftharpoons B$ is:
Given: ${△}_r{H}_{298K}=-54.07kJmo{l}^{-1},{△}_r{S}_{298K}^o=10J{K}^{-1}mo{l}^{-1}andR=8.314J{K}^{-1}mo{l}^{-1};2.303\times 8.314\times 298=5705).$

1. 5
2. 100
3. 95
4. 10

Q.

Which of the following is affected by catalyst?

1. $∆\mathrm{H}$

2. $∆\mathrm{S}$

3. $∆\mathrm{G}$

4. ${\mathrm{E}}_{\mathrm{a}}$

Q. The standard entropy change for the reaction $4Fe\left(s\right)+3O_2\left(g\right)\to 2F{e}_2{O}_3\left(s\right)$ is $–550J{K}^{–1}$ at $298K$.
[Given: The standard enthalpy change for the reaction is $–165kJmo{l}^{–1}]$. The temperature in $K$ at which the reaction attains equilibrium is . (Nearest Integer)

Q. A reaction occurs spontaneously if

1. $T△S<△H$ and both $△H,△S$ are $+ve$
2. $T△S<△H$ and $△H=+ve,△S=-ve$
3. $T△S>△H$ and both $△H,△S$ are $+ve$
4. $T△S=△H$ and both $△H,△S$ are $+ve$

Q.

Out of C and CO, which is a better reducing agent for ZnO ?

Q. The reaction,
$MgO\left(s\right)+C\left(s\right)\to Mg\left(s\right)+CO\left(g\right),$
For which ${△}_r{H}^o=+491.1kJmo{l}^{-1}and{△}_r{S}^{\circ }=198.0J{K}^{-1}mo{l}^{-1}$ is not feasible at 298 K. Temperature above which reaction will be feasible is

1. $2040.5K$
2. $1890.0K$
3. $2480.3K$
4. $2180.5K$

Q.

At 298 K, $K_p$ for reaction $N_2{O}_4\left(g\right)\rightleftharpoons 2N{O}_2\left(g\right)$ is 0.98. Predict whether the reaction is spontaneous or not.

Q.

Given below are two statements:

Statement 1: The ${\mathrm{E}}^{\circ }$value for ${\mathrm{Ce}}^{4+}/{\mathrm{Ce}}^{3+}$ is ${}^{+}1.74\mathrm{V}.$

Statement 2: $\mathrm{Ce}$is more stable in ${\mathrm{Ce}}^{4+}$state than ${\mathrm{Ce}}^{3+}$state

1. Both statement 1 and statement 2 are correct

2. Statement 1 is incorrect but statement 2 is correct

3. Both statement 1 and statement 2 are incorrect

4. Statement 1 is correct but statement 2 is incorrect

Q. Which of the following condition(s) is/are valid for an ideal solution?

1. No change in volume on mixing. $\Delta V_{mix}=0$
   
2. No change in enthalpy on mixing. $\Delta H_{mix}=0$
3. Entropy on mixing $\Delta S_{mix}>0$
4. All of the above.

Q.

Is activation energy dependent on temperature?

Q. Why the sum of mole fractions of the components in solution ie equal to one (1)??

Q. The standard Gibbs energy change at 300 K for the reaction, $2A\rightleftharpoons B+C$ is $2494.2J.$ At a given time, the composition of the reaction mixture is $\left[A\right]=\frac{1}{2}\left[B\right]=2$ and $\left[C\right]=\frac{1}{2}$. The reaction proceeds in the
$(R=8.314JK/mol,e=2.718)$

1. Forward direction because $Q>K_c$
2. Forward direction because $Q<K_c$
3. Reverse direction because $Q<K_c$
4. Reverse direction because $Q>K_c$

Q. For the water gas reaction,
$C\left(s\right)+H_{2}O\left(g\right)\rightleftharpoons CO\left(g\right)+H_2\left(g\right)$
the standard Gibbs free energy of reaction (at $1000K$) is $-8.1kJ/mol.$ Calculate its equilibrium constant

Q. For the reaction
$N_2\left(g\right)+3H_2\left(g\right)\to 2N{H}_3\left(g\right)$
$△H=-95.4kJand△S=-198.3J{K}^{-1}$
Calculate the temperature at which Gibb's energy change $(△G$) is equal to zero.

1. 495 K
2. 430 K
3. 450 K
4. 481 K

Q.

Which of the following is not correct?
(a) $\Delta$ G is zero for a reversible reaction.
(b) $\Delta$ G is positive for a spontaneous reaction.
(c) $\Delta$ G is negative for a spontaneous reaction.
(d) $\Delta$ G is positive for a non-spontaneous reaction.

Q. The molar entropy content of 1 mole of oxygen $\left(O_2\right)$ gas at $300\text{K}$ and $1\text{atm}$ is $250{\text{J mol}}^{-1}{\text{K}}^{-1}$. Calculate $\Delta G$ when 1 mole of oxygen is expanded reversibly and isothermally from $300\text{K}$, $1\text{atm}$ to double its volume (Take $R=8.314{\text{J mol}}^{-1}{\text{K}}^{-1},\text{log}e=2.303$)

1. $1.728{\text{kJ mol}}^{-1}{\text{K}}^{-1}$
2. $0$
3. $-1.728{\text{kJ mol}}^{-1}{\text{K}}^{-1}$
4. $0.75{\text{kJ mol}}^{-1}{\text{K}}^{-1}$

Q. What is the free energy change $\left(△G\right)$ when 1.0 mole of water at ${100}^{o}C$ and 1 atmospheric pressure is converted into steam at ${100}^{o}C$ and 1 atmospheric pressure?

1. 80 cal
2. 540 cal
3. 620 cal
4. zero

Q. The standard reaction Gibbs energy for a chemical reaction at an absolute temperature T is given ${△}_r{G}^{\circ }=A-BT,$ where A and B are non-zero constants. Which of the following is true about this reaction?

1. Endothermic if A > 0
2. Exothermic if B < 0
3. Exothermic if A > 0 and B < 0
4. Endothermic if A < 0 and B > 0

Q.

What is intensive and extensive properties of thermodynamics?

Q. What can be concluded about the values of $△H$ and $△S$ from this graph?

1. $△H>0,△S>0$
2. $△H>0,△S<0$
3. $△H<0,△S>0$
4. $△H<0,△S<0$