Given the following enthalpy changes:

C(graphite) + O₂(g) → CO₂(g)  ΔH = −94.05 kcal mol⁻¹

C(diamond) + O₂(g) → CO₂(g)  ΔH = −94.50 kcal mol⁻¹

Which of the following statements is correct?

1. C(graphite) → C(diamond); ΔH°₂₉₈K = −450 cal mol⁻¹
2. C(diamond) → C(graphite); ΔH°₂₉₈K = +450 cal mol⁻¹
3. Graphite is the more stable allotrope
4. Diamond and graphite are both sp² hybridised

In thermodynamics, a process is called reversible when:

A Beckmann thermometer is used to measure -

1. High temperature

2. Low temperature

3. Normal temperature

4. All temperatures

Which of the following thermodynamic quantities is measured as heat in a bomb calorimeter during a reaction?

When a gas undergoes adiabatic expansion, it gets cooled due to:

1. Loss of energy

2. Fall in pressure

3. Decrease in velocity

4. Increase in energy with work done

Heat is flowing through a conductor of length l from x = 0 to x = l. If its thermal resistance per unit length is uniform, which of the following graphs is correct ?

The heat of formation of HCl(g) from the reaction

H₂(g) + Cl₂(g) $\to <mspace\; width="1em"></mspace>2\mathrm{HCl}\left(\mathrm{g}\right)$; $∆H<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>-44<mspace\; width="1em"></mspace>kcal$ is

1. +44 kcal

2. -44 kcal

3. +22 kcal

4. -22 kcal

If a chemical change is brought about by one or more methods in one or more steps, then the amount of heat absorbed or evolved during the complete course of reaction is same, which ever method was followed. This law is known as:

1. Le Chatelier's principle

2. Hess's law

3. Joule Thomson effect

4. Trouton's law

If 1.00 kcal of heat is added to 1.2 L of oxygen in a cylinder at constant pressure of 1.000 atm, the volume increases to 1.5 L, Hence $∆E$ for this process is:

1. 0.993 kcal

2. 1.0073 kcal

3. 0.0993 kcal

4. 1.00073 kcal

Find the compound with the lowest fuel value (kJ/g) from the following heats of combustion:

CH₄, C₂H₄, and C₂H₆ have heats of combustion −890, −1411, and −1560 kJ/mol, respectively.

1. $\mathrm{CH₄}$

2. ${\mathrm{C₂H₄}}_{}$

3. ${\mathrm{C₂H₆}}_{}$

4. All have same fuel value