HARD
JEE Main/Advance
IMPORTANT
Earn 100

Cesium chloride is formed according to the following equation :

Css+0.5Cl2gCsCls.

The enthalpy of sublimation of Cs, enthalpy of dissociation of chloride, ionization energy of Cs & electron affinity of chlorine are 81.2, 243.0, 375,7 and -348.3 kJ mol-1. The energy change involved in the formation of CsCl is -388.6 kJ mol-1. Calculate the lattice energy of CsCl. (in kJ mol-1) enolved.

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Important Questions on Thermodynamics

HARD
JEE Main/Advance
IMPORTANT
The enthalpy of formation of ethane, ethylene and benzene from the gaseous atom are -2839.2, -2275.2 and -5506 kJ mol-1 respectively. Calculate the modulus of resonance energy of benzene (in kJ mol-1). The bond enthalpy of C-H bond is given as equal to +410.87 kJ/mol.
MEDIUM
JEE Main/Advance
IMPORTANT
Two mole of ideal diatomic gas CV, m=5/2 R at 300 K and 5 atm expanded irreversibly & adiabatically to a final pressure of 2 atm against a constant pressure of 1 atm. Calculate H (in J)
MEDIUM
JEE Main/Advance
IMPORTANT
A bomb calorimeter containing 5.4 g of Al and 15.97 g of Fe2O3 is placed in an ice calorimeter containing initially 8 kg of ice and 8 kg of water. The reaction 2Als+Fe2O3sAl2O3s+2Fes is set off by remote control and it is then observed that the calorimeter contains 7.746 kg of ice and 8.254 kg of water. Find the H for the above reaction. (in kcal)

Hfussionice=1.436 kcal/mole

MEDIUM
JEE Main/Advance
IMPORTANT

A sample of the sugar D-riboseC5H10O5 of mass 0.727 g was placed in a calorimeter and then ignited in the presence of excess oxygen. The temperature was raised by 0.910 K. In a separate experiment in the same calorimeter, the combustion of 0.825 g of benzoic acid, for which the internal energy of combustion is -3251 kJ mol-1, gave a temperature rise of 1.940 K. Calculate the internal energy of combustion of D-ribose in kJ mol-1. Give answer in 2 decimal places.

MEDIUM
JEE Main/Advance
IMPORTANT
The heat of combustion of formaldehydeg is -134 kcal mole-1 and the heat of combustion of paraformaldehydes is -122 kcal per 1/n CH2On. Calculate the heat of polymerization of formaldehyde to paraformaldehyde in kJ mol-1
HARD
JEE Main/Advance
IMPORTANT
The disaccharide α-maltose can be hydrolysed to glucose according to the equation C12H22O11aq+H2Ol2C6H12O6aq

Using the following values, calculate the standard enthalpy change of the above reaction in kJ mol-1.

fH°H2O, l=-285.85 kJ·mol-1

fH°C6H12O6,aq=-1263.1 kJ·mol-1

fH°C12H22O11,aq=-2238.3 kJ·mol-1

HARD
JEE Main/Advance
IMPORTANT
For an ionic solid MX2, where X is monovalent, the enthalpy, the enthalpy of formation of the solid from Ms and X2g is 1.5 times the electron gain enthalpy of Xg. The first and second ionisation enthalpies of the metal M are 1.2 and 2.8 times of the enthalpy of sublimation of Ms. The bond dissociation enthalpy of X2g is 0.8 times the first ionisation enthalpy of metal and it is also equal to one-fifth of the magnitude of lattice enthalpy of MX2. If the electron gain enthalpy of Xg is -96 Kcal/mol, then answer the enthalpy of sublimation of metal M in Kcal/mol.
HARD
JEE Main/Advance
IMPORTANT

Calculate work done in adiabatic compression of one mole of an ideal gas (monoatomic) from an initial pressure of 1atm to final pressure of 2atm. Initial temperature =300K

(a) If process is carried out reversibly

(b) If process is carried out irreversible against 2atm external pressure.

Compute the final volume reached by gas in two cases.