Some Examples of Sublimation Process in Thermodynamics

The physical process known as sublimation takes place when a solid transitions directly from a solid state to a gaseous (vapor) state, without first transitioning through a liquid state. The amount of heat that is required to transform a unit mass of a solid into a unit mass of a gas at a particular temperature is referred to as the latent heat of sublimation. For instance, the amount of latent heat released when ice sublimates at a temperature of 0 degrees Celsius is estimated to be 2,838 kilojoules per kilogramme. This amount of heat is required in order for ice to be converted into vapor. This process is the most important step in the overall process of how ice crystals and snowflakes grow in the atmosphere. This procedure is completely different from the deposition procedure.

Example of Sublimation Process in Thermodynamics

Carbon Dioxide (CO2)

Dry ice melting away in the air

Dry ice, which is made of solid carbon dioxide, melts along the solid-liquid line at pressures and temperatures above the triple point, such as 5.1 atm and 56.6 °C.

Water

At temperatures below the freezing/melting point temperature line at 0 °C and partial pressures below the triple point pressure of 612 Pa, snow and ice melt more slowly (0.00604 atm).

In freeze-drying, the material that needs to be dehydrated is frozen, and its water is then allowed to evaporate in a low-pressure or vacuum environment. During a cold spell, a snowfield often loses snow because the sun is directly hitting the top layers of snow. Ablation is a process that happens when glacier ice melts and wears away. [needs citation]

Naphthalene

Naphthalene is an organic compound that is often found in mothballs and other pesticides. It dissolves easily because it is made of non-polar molecules that are only held together by van der Waals forces. Naphthalene is a solid that turns into a gas at the normal temperature of the atmosphere.The point at which this happens is around 80 °C or 176 °F. At 53 °C, the vapor pressure of naphthalene is 1 mmHg, which is high enough to make the solid form of naphthalene turn into gas. When the naphthalene vapors hit a cool surface, they will solidify into needle-like crystals.

Setting up an experiment to study the sublimation of naphthalene The crystal-like structure at the bottom of the watch glass is made up of naphthalene that has melted.

On the cool surface, a solid compound of naphthalene turned into a structure that looks like a crystal.

Some Other Things

Camphor turning into vapor in the cold finger. The raw product at the bottom is dark brown, while the white product at the end of the cold finger above it is hard to see because the background is light.

When iodine is heated slowly, it gives off fumes, but this is above the triple point, so it is not true sublimation. At atmospheric pressure, it is possible to get liquid iodine by keeping the temperature just above the point where iodine melts. Iodine vapor can be used in forensic science to find hidden fingerprints on paper. [9] At high temperatures, arsenic can also boil off.

Cadmium and zinc aren’t good for use in a vacuum because they evaporate much more quickly than other common materials.

Forces Between Molecules

An intermolecular force (IMF) or secondary force is the force that helps molecules interact with each other. It includes the electromagnetic forces of attraction or repulsion between atoms and other types of nearby particles, like atoms or ions. When compared to intramolecular forces, which hold a molecule together, forces between molecules are weak. For example, the force between two molecules that are close together is much weaker than the force between two atoms that share electron pairs. Both sets of forces are important parts of what are called “force fields,” which are often used in molecular mechanics.

The study of forces between molecules starts with macroscopic observations that show that forces exist and act at the molecular level. Virial coefficients, vapor pressure, viscosity, superficial tension, and absorption data show how non-ideal gasses behave from a thermodynamic point of view.

Alexis Clairaut’s book Théorie de la figure de la Terre, which came out in Paris in 1743, is the first book to talk about the nature of forces on a small scale. Laplace, Gauss, Maxwell, and Boltzmann are some other scientists who have helped figure out how microscopic forces work.

Attractive Forces Between Molecules Can Be Put Into the Following Groups

• The hydrogen bond
• Dipole forces caused by ions
• ions and dipoles
• The Keesom force, the Debye force, and the London dispersion force are all van der Waals forces.

Macroscopic measurements of properties like viscosity, pressure, volume, and temperature (PVT) data can tell us about the forces between molecules. Virial coefficients and Lennard-Jones potentials show how things work on a small scale.

Hydrogen Bonding

Hydrogen bonding is an interaction between a hydrogen atom and two other atoms that have a strong attraction for electrons. This type of bond is weaker than an ionic or covalent bond but stronger than a van der Waals force. Atoms in different molecules or parts of the same molecule can connect with hydrogen bonds. One of the atoms in the pair, called the “donor,” is usually a fluorine, nitrogen, or oxygen atom. It forms a covalent bond with a hydrogen atom (FH, NH, or OH), whose electrons it shares unequally. The hydrogen gets a slight positive charge because of the high electron affinity of the “donor” atom. The other atom in the pair, which is usually F, N, or O, has an electron pair that it doesn’t share with the other atom. This gives it a slight negative charge. The bond is made when the donor atom gives its hydrogen to the acceptor atom, mostly because of electrostatic attraction. Because it has so many hydrogen bonds, water (H2O) is liquid at a much wider range of temperatures than you would think for a molecule its size. Because it easily forms hydrogen bonds with the solute, water is also a good solvent for ionic compounds and many other types of compounds. The way a linear protein molecule folds up into its functional shape is set by the hydrogen bonds between its amino acids. The double-helix structure of DNA is formed by hydrogen bonds between nitrogenous bases in nucleotides on the two strands of DNA (guanine pairs with cytosine, and adenine pairs with thymine). This structure is important for passing on genetic information.

Conclusion

From the following article we can conclude that An intermolecular force (or secondary force) is a force that mediates interactions between molecules, such as electromagnetic forces of attraction or repulsion between atoms or ions. Intermolecular forces are weak compared to intramolecular forces. For example, the covalent link between atoms is substantially stronger than the forces between molecules. Both sets of forces are essential in molecular mechanics force fields.