In a reversible isothermal process, the change in internal energy is-

1. Zero

2. Positive

3. Negative

4. None of the above

The enthalpy of neutralization of which of the following acids and bases is nearly –13.6 Kcal [Roorkee 1999]

(1) HCN and NaOH

(2) HCl and KOH

(3) HCl and HCN

(4) HCl and NH₄OH

What is the work done when one mole of an ideal gas undergoes isothermal expansion from an initial pressure of 10 atm to a final pressure of 1 atm at a constant temperature of 300 K? (Gas constant = 2 calorie )
1. 938.8 cal
2. 1138.8 cal
3. 1381.8 cal
4. 1581.8 cal

Joule-Thomson expansion is [JIPMER 2000]

(1) Isobaric

(2) Isoenthalpic

(3) Isothermal

(4) None of these

In an adiabatic expansion of an ideal gas-

1. W = –ΔE

2. W = ΔE

3. ΔE = 0

4. W = 0

For the reaction

\(C H_{3} C O O H \left(\right. l \left.\right)+ 2 O_{2} \left(\right. g \left.\right) \)
\(\rightleftharpoons 2 C O_{2} \left(\right. g \left.\right)+ 2 H_{2} O \left(\right. l \left.\right)\)
at 25°C and 1 atm. pressure, ΔH = –874 kJ. The change in internal energy (ΔE) is:

1. – 874 kJ
2. – 971.53 kJ
3. + 971.53 kJ
4. + 874 kJ

One mole of an ideal gas is allowed to expand freely and adiabatically into a vacuum until its volume has doubled. A statement that is not true concerning this expression is [Pb. PMT 1998]

1. ΔH = 0

2. ΔS = 0

3. ΔE = 0

4. W = 0

At 27°C, one mole of an ideal gas is compressed isothermally and reversibly from a pressure of 2 atm to 10 atm. The values of ΔE and q are (R = 2)

(1) 0, – 965.84 cal

(2) – 965.84 cal, + 965.84 cal

(3) + 865.58 cal, – 865.58 cal

(4) – 865.58 cal, – 865.58 cal

ΔE° of combustion of isobutylene is –X kJ mol^–1. The value of ΔH° is [DCE 2004]

1. = ΔE°

2. > ΔE°

3. = 0

4. < ΔE°

An ideal gas expands in volume from 1 × 10^–3 m³ to 1 × 10^–2 m³ at 300 K against a constant pressure of 1 × 10⁵ Nm^–2. The work done is [AIEEE 2004]

(1) 270 kJ

(2) –900 kJ

(3) –900 J

(4) 900 kJ