List of top Chemistry Questions on Enthalpy change

Arrange the following elements in increasing order of first ionization enthalpy:
Li, Be, B, C, N
Choose the correct answer from the options given below:

Decreasing order of electron gain enthalpy of the following elements (magnitude only)
Sulphur A, Bromine - B, Fluorine C, Argon D

Find the work done in the following cyclic process (in J)

 

At $25^{\circ} C$, the enthalpy of the following processes are given: $H _2( g )+ O _2( g ) \rightarrow 2 OH ( g ) \Delta H ^{\circ} =78 \,kJ \,mol ^{-1} $ $H _2( g )+1 / 2 O _2( g ) \rightarrow H _2 O ( g ) \Delta H ^{\circ} =-242 \,kJ \,mol ^{-1} $ $H _2( g ) \rightarrow 2 H ( g ) \Delta H ^{\circ} =436\, kJ \,mol ^{-1} $ $1 / 2 O _2( g ) \rightarrow O ( g ) \Delta H ^{\circ} =249\, kJ\, mol ^{-1}$ What would be the value of $X$ for the following reaction?______ (Nearest integer) $H _2 O ( g ) \rightarrow H ( g )+ OH ( g ) \Delta H ^{\circ}= X\, kJ\, mol -1$

Enthalpies of formation of $CCl _4( g ), H _2 O ( g ), CO _2( g )$ and $HCl ( g )$ are $-105,-242,-394$ and $-92\, kJ$ mol $^{-1}$ respectively The magnitude of enthalpy of the reaction given below is ___$kJ \, mol ^{-1}$ (nearest integer) $CCl _4( g )+2 H _2 O ( g ) \rightarrow CO _2( g )+4 HCl ( g )$

The difference between electron gain enthalpies will be maximum between

The correct order of hydration enthalpies is
(A) K⁺ 
(B) Rb⁺p 
(C) Mg²⁺ 
(D) Cs⁺ 
(E) Ca²⁺ 
Choose the correct answer from the options given below:

Which of the following 3d-metal ion will give the lowest enthalpy of hydration (Δ_hydH) when dissolved in water?

The enthalpy of combustion of propane, graphite and dihydrogen at 298 K are –2220.0 kJ mol^–1, –393.5 kJ mol^–1 and –285.8 kJ mol^–1, respectively.The magnitude of enthalpy of formation of propane (C₃H₈) is _____ kJ mol^–1. (Nearest integer)

2.4 g coal is burnt in a bomb calorimeter in excess of oxygen at 298 K and 1 atm pressure. The temperature of the calorimeter rises from 298 K to 300 K. The enthalpy change during the combustion of coal is –x kJ mol^–1. The value of x is ______.(Nearest integer)
(Given : Heat capacity of bomb calorimeter is 20.0 kJ K^–1. Assume coal to be pure carbon)

The first ionization enthalpy of Na, Mg and Si, respectively, are : 496, 737 and 786 kJ mol^–1. The first ionization enthalpy (kJ mol^–1) of Al is:

At 25°C and 1 atm pressure,the enthalpies of combustion are as given below:

\(Substance\)	\(H_2\)	\(C(graphite)\)	\(C_2H_6(g)\)
\(\frac{D_cH^{\theta}}{kJmol^{-1}}\)	\(-286.0\)	\(-394.0\)	-1560.0

The enthalpy of formation of ethane is

At 25°C and 1 atm pressure, the enthalpy of combustion of benzene (I) and acetylene (g) are –3268 kJ mol^–1 and –1300 kJ mol^–1, respectively. The change in enthalpy for the reaction 3C₂H₂(g) → C₆H₆(I), is

For complete combustion of methanol
\( CH_3OH(I)+\frac 32O_2(g)→CO_2(g)+2H_2O(I)\)
the amount of heat produced as measured by bomb calorimeter is \(726\) kJ mol^–1 at \(27°C\). The enthalpy of combustion for the reaction is \(x \ kJ mol^{–1}\), where \(x\) is ______ . (Nearest integer)
(Given: \(R= 8.3 \ JK^{–1}mol^{–1}\))

An element A of group1 shows similarity to an element B belonging to group 2. If A has maximum hydration enthalpy in group 1 then B is:

The incorrect statement is

17.0 g of NH₃ completely vapourises at – 33.42°C and 1 bar pressure and the enthalpy change in the process is 23.4 kJ mol^–1 . The enthalpy change for the vapourisation of 85 g of NH₃ under the same conditions is ____ kJ.

The standard enthalpy of formation of CH₄(g), CO₂(g) and H₂O(I) are -75 kJ mol^-1, -393 kJ mol^-1 and -286 kJ mol^-1 respectively. The amount of heat liberated (in kJ) when 3.2g of methane gas is burnt under standard conditions is

Which of the following relation is not correct?

The first ionisation enthalpy is the least in

An ideal gas undergoes a reversible isothermal expansion from the state I to state II followed by a reversible adiabatic expansion from state II to state III. The correct plot(s) representing the changes from the state I to state III is(are) 
(p: pressure, V: volume, T: temperature, H: enthalpy, S: entropy)

The enthalpy change for the evaporation of a liquid at its boiling point 127°C is +40.32 $kJmol^{-1}$. What is the value of internal energy change for the above process at 127°C? (R=8.3 $JK^{-1}mol^{-1}$)