HARD
JEE Main
IMPORTANT
Earn 100

For combustion of one mole of magnesium in an open container at 300 K and 1 bar pressure, ΔCH=-601.70 kJ mol-1, the magnitude of change in internal energy for the reaction is kJ. (Nearest integer)
(Given : R=8.3 J K-1 mol-1)

40% studentsanswered this correctly

Important Questions on Thermodynamics

EASY
JEE Main
IMPORTANT
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.
MEDIUM
JEE Main
IMPORTANT

2.2 g of nitrous oxide N2O gas is cooled at a constant pressure of 1 atm from 310 K to 270 K causing the compression of the gas from 217.1 mL to 167.75 mL. The change in internal energy of the process, U is '-x'J. The value of 'x' is _____.

[nearest integer]

(Given: atomic mass of N=14 g mol-1 and of O=16 g mol-1. Molar heat capacity of N2O is 100 JK-1 mol-1)

MEDIUM
JEE Main
IMPORTANT
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 _____ kJmol-1. (Nearest integer)
MEDIUM
JEE Main
IMPORTANT

While performing a thermodynamics experiment, a student made the following observations, HCl+NaOHNaCl+H2OΔH=-57.3 kJ mol-1

CH3COOH+NaOHCH3COONa+H2O

ΔH=-55.3 kJ mol-1.

The enthalpy of ionization of CH3COOH as calculated by the student is kJ mol-1

MEDIUM
JEE Main
IMPORTANT

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_____(Given : Heat capacity of bomb calorimeter 20.0 kJK-1. Assume coal to be pure carbon)

MEDIUM
JEE Main
IMPORTANT

For the reaction H2F2gH2g+F2g

ΔU=-59.6 kJ mol-1 at 27 °C

The enthalpy change for the above reaction is -____ kJmol-1 (nearest integer)

(Given : R=8.314JK-1 mol-1) .

HARD
JEE Main
IMPORTANT

The molar heat capacity for an ideal gas at constant pressure is 20.785 J K-1 mol-1. The change in internal energy is 5000 J upon heating it from 300 K to 500 K. The number of moles of the gas at constant volume is____

(Given: R=8.314 J K-1 mol-1)

HARD
JEE Main
IMPORTANT
A gas ( Molar mass =280 g mol-1) was burnt in excess O2 in a constant volume calorimeter and during combustion the temperature of calorimeter increased from 298.0 K to 298.45 K. If the heat capacity of calorimeter is 2.5 kJ K-1 and enthalpy of combustion of gas is 9 kJ mol-1 then amount of gas burnt is____g.