is the molar mass value of a volatile liquid, such as ethanol, high or small?
Usually small, but there are exceptions. The ability to be volatile means that the attractive forces between molecules in the liquid and vapor have to be small, so non polar molecules are the rule. Also, to get motion to escape the surface of the liquid, thermal energy can move smaller masses faster (KE= 1/2 mass*velocity^2). Lighter molecules can escape easier.
To determine if the molar mass value of a volatile liquid, such as ethanol, is high or small, you can consider a few factors.
Volatile liquids are substances that readily evaporate at relatively low temperatures. The ability to be volatile indicates that the attractive forces between the molecules in the liquid and vapor phases are relatively weak. That means volatile liquids are typically composed of molecules with relatively small intermolecular forces.
In general, non-polar molecules tend to have weaker intermolecular forces compared to polar molecules. This is because non-polar molecules have symmetrical electron distribution, resulting in no significant partial charges. Ethanol (C2H5OH) is a polar molecule due to the presence of the oxygen atom, but its volatility is still relatively high due to weak intermolecular forces.
Additionally, the molar mass of a compound also plays a role in determining its volatility. The molar mass represents the mass of one mole of a substance. When considering the evaporation or boiling process, lighter molecules can escape more easily from the liquid surface. This is because the thermal energy (kinetic energy) required to move a smaller mass at a certain velocity is lower compared to a large mass. The formula for kinetic energy, KE= 1/2 mass * velocity^2, shows that smaller masses can achieve higher velocities with the same amount of energy.
Therefore, to answer your question, the molar mass of a volatile liquid, such as ethanol, is typically relatively small. But it is important to note that there can be exceptions depending on the specific molecular structure and intermolecular forces present in the substance.