Q1: Except for monoatomic gases, the molal heat capacity at constant volume for all gases is __________ Kcal/Kg mole.° K.

ANS:B - > 3

The heat capacity of a substance measures how much energy is required to raise the temperature of a given amount of that substance by one degree Celsius (or one Kelvin). For monoatomic gases, such as helium (He), neon (Ne), and argon (Ar), their heat capacities are approximately 3 Kcal/kg mole.°K. This value arises because monoatomic gases primarily store energy in translational motion, meaning they only have three degrees of freedom in which they can store kinetic energy (movement in three spatial dimensions). However, for most other gases, such as diatomic gases like nitrogen (N2), oxygen (O2), and carbon dioxide (CO2), additional degrees of freedom come into play due to rotation and vibration of their molecular structures. These additional degrees of freedom allow these molecules to store more energy, resulting in higher heat capacities compared to monoatomic gases. The actual value for the molal heat capacity at constant volume for most gases (excluding monoatomic gases) is generally higher than 3 Kcal/kg mole.°K. It can vary depending on factors such as temperature and pressure, but it's typically greater than 3 Kcal/kg mole.°K.