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First law, work, heat, internal energy, enthalpy

36 questions on First law, work, heat, internal energy, enthalpy from the Thermodynamics and Thermochemistry chapter: 8 NEET level, 14 JEE Main, 14 JEE Advanced. Each one opens with its answer and solution.

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For the reversible isothermal expansion of one mole of an ideal gas, which pair of relations is correct? (IUPAC convention: w is work done on the system.) NEET level
For N2(g) + 3H2(g) -> 2NH3(g) at 300 K, taking gases as ideal (R = 8.314 J mol^-1K^-1), the value of Delta H - Delta U is closest to NEET level
Which of the following has a standard enthalpy of formation equal to zero at 298 K and 1 bar? NEET level
A system absorbs 250 J of heat and does 90 J of work on its surroundings. The change in internal energy of the system is NEET level
Two moles of an ideal gas expand reversibly and isothermally at 300 K from 5.0 L to 20 L. Taking R = 8.314 J mol^-1K^-1, the work w (IUPAC sign convention, work... JEE Main level
The standard internal energy change of combustion of C6H6(l) at 298 K measured in a bomb calorimeter is -3263 kJ mol^-1 for C6H6(l) + 7.5 O2(g) -> 6CO2(g) + 3H2... JEE Main level
A 0.800 g sample of naphthalene (C10H8, M = 128 g mol^-1) is burnt completely in a bomb calorimeter whose heat capacity (including contents) is 10.20 kJ K^-1. T... JEE Main level
One mole of an ideal gas at 310 K and 10 atm expands isothermally against a constant external pressure of 2 atm until its pressure becomes 2 atm. Take R = 8.314... JEE Main level
The enthalpy of vaporisation of water at 373 K and 1 atm is 40.7 kJ mol^-1. Treating the vapour as ideal and neglecting the volume of the liquid (R = 8.314 J mo... JEE Main level
At 300 K, treating all gases as ideal, which of the following statements is/are correct? JEE Main level
Consider one mole of an ideal gas. Which statements are correct? JEE Main level
The standard internal energy of combustion of C2H6(g) at 298 K is -1555.0 kJ mol^-1 (products CO2(g) and H2O(l)). Given Delta_f H deg(CO2,g) = -393.5 and Delta_... JEE Advanced level
One mole of a monatomic ideal gas at 2.0 atm and 10 L is expanded at constant pressure to 20 L, and then cooled at constant volume until the pressure is 1.0 atm... JEE Advanced level
One mole (18.0 g) of ice at -10 degC is converted to steam at 100 degC at 1 atm. Data: c_p(ice) = 2.09, c_p(water) = 4.18 J g^-1K^-1; Delta_fusH = 6.01 kJ mol^-... JEE Advanced level
One mole of a monatomic ideal gas (R = 8.314 J mol^-1K^-1) undergoes a cycle: 1->2 isochoric heating from 300 K until the pressure doubles; 2->3 reversible isot... JEE Advanced level
In a calorimeter of heat capacity 20.0 J K^-1, 50.0 mL of 1.00 M weak acid HA is mixed with 50.0 mL of 1.00 M NaOH; the temperature rises by 6.00 K. Assume the ... JEE Advanced level
Two moles of an ideal gas at 300 K and 10 atm expand isothermally against a constant external pressure of 1 atm until the pressure is 1 atm. The gas is then com... JEE Advanced level
For KCl(s): Delta_fH = -436.7, enthalpy of sublimation of K = 89.2, ionisation enthalpy of K = 418.8, (1)/(2) bond dissociation enthalpy of Cl2 = 121.7, electro... JEE Advanced level
One mole of an ideal gas expands isothermally into an evacuated rigid container (free expansion). Which set of values is correct (IUPAC sign convention)? NEET level
Which of the following is NOT a state function? NEET level
For which of the following reactions at constant temperature is Delta H = Delta U? NEET level
A gas in an insulated cylinder is compressed by a piston, and 500 J of work is done on the gas. What is the change in internal energy of the gas? NEET level
Two moles of a monatomic ideal gas are heated at constant pressure from 300 K to 400 K. Taking R=8.314 J mol^-1K^-1, calculate Delta U of the gas in joules (nea... JEE Main level
Two moles of an ideal gas expand reversibly and isothermally at 300 K from 2.0 L to 10.0 L. Using R=8.314 J mol^-1K^-1 and ln 5=1.609, calculate the magnitude o... JEE Main level
A gas expands irreversibly from 2.0 L to 12.0 L against a constant external pressure of 2.0 atm. Taking 1 L atm=101.3 J, the work w (IUPAC convention, work done... JEE Main level
Two moles of an ideal diatomic gas (C_V=tfrac52R) are heated at constant pressure from 300 K to 350 K. With R=8.314 J mol^-1K^-1, the enthalpy change Delta H is... JEE Main level
One mole of an ideal monatomic gas expands reversibly from the same initial state (P_1,V_1,T_1) to the volume 2V_1, once isothermally and once adiabatically. Se... JEE Main level
36 g of liquid water at its boiling point (373 K, 1 atm) is converted completely to steam at the same temperature and pressure. Given Delta_vapH=40.7 kJ mol^-1 ... JEE Main level
A system undergoes a cycle of three steps and returns to its initial state. It absorbs 300 J of heat in step 1, releases 120 J in step 2 and absorbs 40 J in ste... JEE Main level
One mole of a monatomic ideal gas at 300 K expands reversibly and adiabatically to twice its initial volume. Take R=8.314 J mol^-1K^-1 and gamma=5/3. Find the w... JEE Advanced level
One mole of an ideal monatomic gas (C_V=tfrac32R) at 305 K and 1.0 bar is compressed adiabatically by a constant external pressure of 3.0 bar until it reaches m... JEE Advanced level
One mole of a monatomic ideal gas at 400 K expands from volume V to 2V along the path PV^1.2=constant. With R=8.314 J mol^-1K^-1, the heat exchanged by the gas ... JEE Advanced level
Two moles of a monatomic ideal gas at 300 K and 10 L expand reversibly to 20 L, once isothermally and once adiabatically. Use R=8.314 J mol^-1K^-1. Select the c... JEE Advanced level
A fixed amount of a monatomic ideal gas (C_V=tfrac32R) is taken through a rectangular cycle on a P-V diagram: (2P_0,V_0)->(2P_0,2V_0) (isobaric expansion) ->(P_... JEE Advanced level
Two moles of an ideal diatomic gas (C_V=tfrac52R) are heated from 300 K to 340 K along the reversible path PV^3=constant. Using R=8.314 J mol^-1K^-1, find the h... JEE Advanced level
50 g of ice at 0 degC is dropped into 200 g of water at 40 degC in an insulated container (negligible heat capacity). Take the heat of fusion of ice as 334 J g^... JEE Advanced level