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Everything that surrounds us is made up of millions of small particles called atoms. These are invisible to the naked eye, but they are the basic components of this universe. The study of these substances and how their composition plays an important role in our daily lives is a very important part of applied science.
The concept of moles is useful when talking about atoms and their properties.
What is a mole?
To introduce the concept of moles, we first discuss Avogadro’s number / constant equal to 6.02214076 × 10²³. When talking about the number of moles of a substrate, divide the total number of particles of molecule / compound / atom by Avogadro’s constant.
Therefore, the 6.02214076 x 10²³ molecule of oxygen molecule (O²) constitutes 1 mole of oxygen, and similarly the 6.02214076 x 10²³ carbon atom constitutes 1 mole of carbon. In other words, when we say that there is 1 mol of substance in the sample, it means that 6.02214076 × 10²³ of that particular element is present in the sample. Therefore, a mole is a unit such as kilogram or centimeter and refers to a specific measure of the number of atoms or molecules contained in a substance. One mole of element contains the same amount of atoms as one mole of other elements. However, the mass of 1 mol varies from element to element.
What does molar mass mean?
The molar mass of an element means the total mass of 1 mol of the element. Relative molar mass is the smallest unit mass of a compound when compared to one-twelfth of the mass of a carbon-12 atom. This means that the number of atoms present in 12 grams of carbon-12 is the same as the number of moles present in 1 mole of carbon. Using a mass spectrometer, we found that the mass of a carbon-12 atom is 1.992648 × 10⁻²³g. The total number of subatomic particles such as atoms and molecules that exist in each element is collectively called mole.
Strictly speaking, atomic mass refers to the mass of a single atom of an element and is expressed in atomic mass units (u). 1 atomic mass unit = 1.67377×10−24 g
The molar mass of an element is the mass of 1 mol of the atom of that element. Therefore, numerically, the molar mass = (6.02214076 × 10²³ * atomic weight of this element).
What does molecular weight mean?
The term is used to refer to the mass of a single molecule of a particular compound or element. The molecular weight of an element or compound is calculated by first calculating the number of atoms bonded within the molecule and then adding them to each atomic mass unit.
The molecular weight is expressed in Dalton (Da), where 1Da corresponds to 1u.
What is the mole fraction?
Mole fraction is also a way of expressing the concentration of a substance in a mixture. In a mixed solution containing different amounts of different elements, the concentration (X) of a particular element is expressed by dividing the number of moles of an existing element by the number of moles of other components and the total number of moles. .. (X) is included.
Mole fraction of solute = number of moles of solute / number of moles of (solute + solvent)
The mole fraction is dimensionless because it is just a ratio.
Percent composition
Percent composition, another indicator of concentration, also indicates the percentage of the mass that the mass contributes to the total mass of the mixture. The percentage composition formula is obtained from the following results.
Percent composition = (mass of individual component / mass of mixture) * 100.
Using methane as an example, the percentage composition of methane is 74% carbon and 25% hydrogen, but there are more hydrogen atoms.
What does the molecular weight indicate?
To understand this, it is important to first know what the relative atomic mass refers to. This simply means having a single uniform atomic weight for an element that can have many different isotopes, such as: B. Carbon. The relative atomic mass of an element can be found by averaging the isotope masses weighted according to their abundance. We discussed
Therefore, molecular weight is the sum of the relative atomic masses of all the elements present in a compound.
Meaning of molar concentration
Molarity is a very common indicator of the concentration that determines the number of moles of a chemical species (solute) dissolved in a liter of solvent. To determine the molar concentration, first find the number of moles present in the solution. To do this, divide the amount of substance dissolved in 1 L of solvent by the molar mass of the substance to determine the molar concentration.
Conclution
Mole is all very well to calculate the atomic molecular and formula masses of atoms, molecules, and other compounds, but since we cannot weigh an individual particle, these masses have a limited usefulness. To make measurements of mass useful we must express chemical quantities at the macroscopic level. The bridge between the particulate and the macroscopic levels is molar mass, the mass in grams of one mole of a substance. We discussed about meaning molar mass, percentage of Composition, molar concentration,etc.
