Abnormal Value of Molar Mass

Introduction

Molar masses that are calculated either lower or higher than expected values (generally using colligative properties) are referred to as abnormal molar masses. The abnormal molar mass is determined by the total number of moles of particles after dissociation or association of solute molecules in solvent or solution.

NaOH molar mass

Sodium Hydroxide is a solid ionic compound. Caustic soda, Iye, sodium hydrate, and soda lye are other names for it.

It is a byproduct of the chlorine production process. It is a crystalline solid that is colorless in nature in its pure form. This compound is made up of sodium cations and hydroxide anions and is highly water-soluble. NaOH is capable of absorbing moisture from the air. It is highly corrosive and can cause severe skin burns as well as eye and other body irritation.

It produces a lot of heat, so it’s always made by mixing the compound into the water, not the other way around. This inorganic compound is used in cosmetics as a buffering agent. It can also regulate the pH levels. pH of Sodium hydroxide is 13.

Properties of Sodium Hydroxide – NaOH

Sodium Hydroxide is a crystalline solid that is white and translucent. Because of its corrosive action on many substances, it is commonly referred to as caustic soda. It decomposes proteins at room temperature and may cause chemical burns to human bodies. Although it does not occur naturally, sodium hydroxide has been mass-produced for many years from readily available raw materials and is used in a variety of industrial processes.

• NaOH

Sodium Hydroxide

• Molecular Weight/ Molar Mass

39.997 g/mol

• Density

2.13 g/cm³

• Boiling Point

1,388 °C

• Melting Point

318 °C

Sodium Hydroxide – NaOH Preparation

On a business scale, hydrated oxide (sodium hydroxide) is ready by a solution of salt (Na2CO3) is treated with hot milk of lime i.e Ca(OH)2 in an exceedingly large tank created of iron.

 Na2CO3 +  Ca(OH)2  →  CaCO3 + 2NaOH

Filtration removes the precipitate of calcium carbonate (CaCO3), and the solution is used to make paper, soap, and detergents.

Uses of Sodium Hydroxide- NaOH

• It’s used in the production of detergents and soaps.
• It is used to create bleach-like chlorine.
• It’s found in drain cleaners.
• It is used in municipal water treatment facilities to remove heavy metals from water.
• It is also used in food preservatives to prevent bacteria and mold growth.
• It is used in the canning process. It is also used in the papermaking and recycling processes.

Health Hazards of Sodium Hydroxide

• If you come in direct contact with highly concentrated sodium hydroxide, it may result in severe burns to the eyes, skin, digestive tract, or lungs and sometimes can result in permanent damage or death.

• Mucous membranes in the nose, throat, lungs and bronchial system may be compromised. Even small doses can also cause serious harm.

• It burns the skin and harms the eyes. The respiratory tract has become inflamed. Irritation of the nasal mucous membranes.
• Avoid contacting your eyes, skin, or clothing. Inhaling gas, fumes, dust, mist, vapor, and aerosols is not recommended. Wear protective eyewear, gloves, and clothing. Acids should never be combined. When working with chemical substances, do not eat, drink, smoke, or use personal care products.

The molecular mass of sodium

23 g/mol is the molecular mass of sodium. Atomic mass is the total count of neutrons and protons in an atom. Dalton is the atomic mass unit, the unit that defines the mass of an atom. It is denoted as Da and is the standard unit for expressing the mass of an atom. The atomic mass of elements varies due to the number of protons and neutrons in each element.

The atomic mass of sodium

Sodium is an alkali metal that ranks first in the third period of the periodic table. It is the table’s eleventh element.

• Sodium’s atomic number is 11
• The number of neutrons present in the nucleus of sodium is equal to 12.
• Sodium (Na) has an atomic mass number of 11 + 12 = 23.

∴Sodium’s atomic mass is 23 g/mol.

Atomic mass in grams

The mass of one mole of an element is equal to its gram atomic mass. It is calculated by taking an element’s atomic weight from the periodic table and converting it to grams. As an example, sodium (Na) has an atomic weight of 22.99 u, which translates to a gram atomic mass of 22.99 grams.

Atomic mass

Every particle of matter, no matter how small or large, has some amount of mass associated with it. Atoms make up everything. This is commonly expressed in terms of a unified atomic mass unit, as agreed upon by the international community (amu).

It is best defined as one-twelfth of the mass of a carbon-12 atom in its ground state. The sum of the masses of protons and neutrons, which is nearly equal to the atomic mass, can account for the mass of an atom. The binding energy mass loss is responsible for this minor change.

1 amu = 1.66 ×10−24 g

• When divided by unified atomic weight or Daltons, an atom’s atomic weight becomes a dimensionless number.

• This is referred to as the relative isotopic mass.

• Elements’ atomic masses range from 1.008 amu for hydrogen to 250 amu for elements with a very high atomic number.

• Molecule mass can be calculated by adding the average atomic mass of each atom in the molecule.

Atomic Mass of Elements

The atomic masses of some elements are listed below.

Atomic Mass of Iron

55.845 u

Atomic Mass of Chlorine

35.453 u

Atomic Mass of Sulfur

32.065 u

Atomic Mass of Copper

63.546 u

Atomic Mass of Potassium

39.0983 u

Atomic Mass of Nitrogen

14.0067 u

Atomic Mass of Calcium

40.078 u

Atomic Mass of Phosphorus

30.973762 u

Atomic Mass of Sodium

22.989769 u

Conclusion 

When we calculate the colligative properties of solutions, the values of molar mass obtained theoretically values of molecular mass are sometimes found to differ from experimentally obtained values. These are commonly referred to as abnormal molar masses. When solutes are dissolved in a solvent, they dissociate into ions, according to Van’t Hoff. Because colligative properties are solely determined by the number of solute particles, the dissociation of solute molecules into ions increases the number of particles and thus affects the colligative properties.

If 1 mole of NaCl is dissolved in 1 kg of water and all the molecules of NaCl dissociate in water, the resulting solution will contain 1 mole of Cl– ions and 1 mole of Na+ ions (a total of 2 moles of ions in the solution). However, when calculating the molar mass using the colligative properties, we assume that the solution contains only 1 mol of NaCl.

Some substances tend to associate in the aqueous state, and the number of ions/molecules present in the solution for such molecules is less than the actual number of molecules. As a result, for those substances that dissociate in solution, the observed molar mass is always less than the real mass, and for those that associate in solution, the real mass is always less than the observed molar mass.

The molecular mass anomaly can be explained as follows:

• When solute molecules dissociate into multiple ions, the number of particles increases. This, in turn, improves the solution’s colligative properties.

• Because molar mass is inversely proportional to colligative properties, its value is typically lower than expected.

• When solute particles associate with one another, the total number of particles in the solution decreases, causing the colligative properties to decrease.

• The molar mass values obtained in this case are higher than expected.