Thermodynamics practice · Mixed difficulty

$\Delta_{\mathrm{f}} H^{\circ}$ for $\mathrm{NF}_3(\mathrm{g})$ is $-113 \mathrm{~kJ} / \mathrm{mol}.$ Bond energy for the $\mathrm{N}-\mathrm{F}$ bond is $273.5 \mathrm{~kJ} / \mathrm{mol}.$ The bond energies of $\mathrm{N}_2$ and $\mathrm{F}_2,$ if their magnitudes are in the ratio $6: 1,$ are respectively.

The term $-T \Delta S_{\text {total}}$ at constant temperature and pressure is known as

well stoppered thermos flask contains some ice cubes. This is an example of

Assertion: The enthalpy of atomization increases with an increase in atomic number in a period.

Reason: The increase in atomic number results in an increase in the number of protons and electrons in the atom.

Internal energy and pressure of a gas of unit volume are related as:

Which compound will absorb the maximum amount of heat when dissolved in the same amount of water? (Integral heats of solution at ${25^0}c$ in kcal/mol of each solute are given in brackets):

The reaction between ${H}_2$ and ${O}_2$ to produce water vapour is given by the equation : $2 {H}_2({~g})+{O}_2({~g}) \longrightarrow 2 {H}_2 {O}({g})$
The work done at STP is :

If the bond energies of $\mathrm{C}=\mathrm{C}$ and $\mathrm{C}-\mathrm{C}$ at $298 \mathrm{~K}$ are $590$ and $331 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively then enthalpy of polymerization per mole of ethylene is:

Enthalpies of combustion of $\mathrm{CH}_4, \mathrm{C}_2 \mathrm{H}_6$ and $\mathrm{C}_3 \mathrm{H}_8$ are $-210,-370$ and $-526 \mathrm{~kcal} / \mathrm{mol},$ respectively. Enthalpy of combustion of hexane can be predicted as

2.1 g of Fe combines with S evolving 3.77 kJ. The heat of formation of FeS in kJ/mole is

In which of the given reactions, $\Delta {H} > \Delta {U}$ ?

Condition for spontaneity in an isothermal
process is

(A): The heat absorbed during isothermal expansion of an ideal gas against vacuum is zero.

(R) : The volume occupied by the molecules is zero.

The enthalpy of vapourisation of water = 45.953 kJ/mol. At 1 atm pressure the boiling point of water is 373 K. What is the boiling point of water when pressure equal to 1/2 atm in Kelvin in nearest possible integers? Given: $\log 2=0.3$

Reaction

1. $\mathrm{C}+\mathrm{O}_2 \rightarrow \mathrm{CO}_2$ $\quad$ ; $\Delta \mathrm{G}=-380 \mathrm{~KJ}$

$\text { 2. } 4 \mathrm{Al}+3 \mathrm{O}_2 \rightarrow 2 \mathrm{Al}_2 \mathrm{O}_3 \quad ; \Delta \mathrm{G}=-2250 \mathrm{~KJ}$

Reduction of $\mathrm{Al}_2 \mathrm{O}_3$ in presence of carbon is possible or not ?

For the reaction; $\;{\mathrm{C}_2}{\mathrm{H}_5}\mathrm{OH}\left( l \right) + 3{\mathrm{O}_2}\left( \mathrm{g} \right) \to \;2C{O_2}(g) + 3{H_2}O(l)$ which one is true?

Three moles of an ideal gas are expanded isothermally from a volume of $300 \mathrm{~cm}^3$ to $2.5 \mathrm{~L}$ at $300 \mathrm{~K}$ against a pressure of $1.9 \mathrm{~atm}$. The work done in joules is

For a specific work, on an average a person requires $5616 \mathrm{~kJ}$ of energy. How many kilograms of glucose must be consumed if all the required energy has to be derived from glucose only? $\Delta H$ for combustion of glucose is $-2808 \mathrm{~kJ} \mathrm{~mol}^{-1}.$

Consider following statements:
(a) The absolute value of internal energy cannot be
evaluated.
(b) Entropy is a state function and extensive
property
(c) Temperature is an extensive property
(d) The standard enthalpy of formation of an element $\left(\Delta \mathrm{H}_{\mathrm{f}}\right)$ is always considered to be zero

(e) For an adiabatic process $\Delta S>0$
wrong statements are :

One mole of an ideal gas undergoes a reversible process in which the entropy of the gas changes with absolute temperature $T$ as $S=a T+C_{\mathrm{v}, \mathrm{m}}$ $\ln T,$ where $a$ is a positive constant. If $T=T_0$ at $V=V_0,$ then the volume dependence of the gas on temperature in this process is

Heat of combustion of glucose is $-2520 \mathrm{~kJ} / \mathrm{mol}$ then calculate the moles of required $\mathrm{O}_2$ when amount of heat evolved is $504 \mathrm{~kJ}$ ?

An athlete in the weight room lifts a $50 \mathrm{~kg}$ mass through a vertical distance of $2.0 \mathrm{~m}.$ The mass is allowed to fall through the $2.0 \mathrm{~m}$ distance while coupled to an electrical generator. The electrical generator produces an equal amount of electrical work, which is used to produce aluminium by Hall electrolytic process.

$\begin{aligned} & {Al}_2 {O}_3 \text {(Solution)}+3 {C}(\text {Graphite}) \rightarrow 2 {Al}({l})+ 3 {CO}(\mathrm{g}) ; \Delta G^{\circ}=600 \mathrm{~kJ} \end{aligned}$

How many times must the athlete lift the $50 \mathrm{~kg}$ mass to provide sufficient Gibbs energy to produce $27 \mathrm{~g} \, {Al}?$ $\left(g=10 \mathrm{~m} / \mathrm{s}^2\right)$

Hess’s law is based on

The heat evolved during neutralisation is maximum in the reaction of :

Assertion :- At constant temperature $0^{\circ} \mathrm{C}$ and $1 \mathrm{~atm}$, the change $\mathrm{H}_2 \mathrm{O}(\mathrm{s}) \rightarrow \mathrm{H}_2 \mathrm{O}(\ell), \Delta \mathrm{H}$ and $\Delta \mathrm{E}$ both are zero.

Reason :- During isothermal process $\mathrm{H}$ and $\mathrm{E}$ both remains constant.

Gibbs energy G, enthalpy H and entropy S are related by:

The enthalpy changes of formation of the gaseous oxides of nitrogen $(\;{N_2}OandNO)$ are positive because of:

The enthalpies of elements in their standard states are taken as zero. The enthalpy of formation of a compound

Given that
(i) $\mathrm{CH}_3 \mathrm{CHO}+\frac{5}{2} \mathrm{O}_2 \rightarrow 2 \mathrm{CO}_2+2 \mathrm{H}_2 \mathrm{O}$; $\Delta \mathrm{H}=-1168 \mathrm{~kJ} \mathrm{~mol}^{-1}$
(ii) $\mathrm{CH}_3 \mathrm{COOH}+2 \mathrm{O}_2 \rightarrow 2 \mathrm{CO}_2+2 \mathrm{H}_2 \mathrm{O}$ ; $\Delta \mathrm{H}=-876 \mathrm{~kJ} \mathrm{~mol}^{-1}$
$\Delta \mathrm{H}$ for the reaction, $\mathrm{CH}_3 \mathrm{CHO}+\frac{1}{2} \mathrm{O}_2 \rightarrow \mathrm{CH}_3 \mathrm{COOH}$, is

Predict which of the following reactions has a negative entropy change?

I. ${CH}_4({~g})+2 {O}_2({~g}) \rightarrow {CO}_2({~g})+2 {H}_2 {O}(\ell)$

II. ${Ag}_{({aq})}^{+}+{Cl}_{({aq})}^{-} \rightarrow {AgCl}({s})$

III. ${H}_2({~g}) \rightarrow 2 {H}({g})$