As mentioned in the text "What is a chemical solution?”, the solutions are homogeneous mixtures in which most of the time the solute (dissolving substance) is in smaller amounts and the solvent (substance that dissolves the solute) is in greater quantity.
In everyday life, depending on the amount of solute and solvent present in the solution, we usually say that it is weak or strong, indicating its saturation. For example, when we prepare a juice by dissolving the powder in water, if we add a little powder and drink it, we can say that the juice is weak (diluted). But if we manage to dissolve a very large amount of powder in water, we will say that the juice is strong (concentrated).
However, there are certain occasions when the amount of solute and solvent present in the solution must be exact, as in the case of intravenous injections (such as saline) and solutions used in laboratories and industries chemical.
The greatness that links this is concentration. So, we can give the following definition:
“Concentration of chemical solutions refers to the amount of solute that exists in a standard amount of solution or in a standard amount of solvent.”
The concentrations of solutions can be measured using different units or numerical relationships, which depend on the quantities being related. The main concentrations used are shown below. When looking at their mathematical formulas, note that indices are used to differentiate when it comes to the solute (index 1), the solvent (index 2), and the solution (no index):
* common concentration or mass concentration(Ç):Lists the amount of mass of solute present in a given volume of solution. Your SI unit is grams per liter (g/L):
C = m1
V
* Concentration in amount of matter or concentration in mol/L (M):It is also known as molar concentration and molarity. Lists the amount of matter (mol) of the solute present in a given volume of solution. Its SI unit is mol per liter (mol/L):
M = no1or M =__m1__
V M1. V
* Density (d):Lists the amount of solution mass (solvent mass + solute mass) and the volume of that solution. Its SI unit is grams per liter (g/mL):
d = m or d = m1 + m2
V V
* Ttitle or mass percentage(τ):Lists the mass of the solute and the mass of the solution. It has no unit or is spoken in terms of percentage:
τ = m1or τ = ___m1___
m m1 + m2
When we want to indicate the percentage in mass, just multiply the result obtained by 100%.
An example is the saline shown below, which is a solution of distilled water with NaCl. So when we see on their labels the percentage by mass equal to 0.9%, this means that 100g of the solution contains 0.9 gram of NaCl. Thus, we can conclude that your title is equal to 0.009.
There is also the ttitle in volume which relates the volume of the solute and the volume of the solution:
τv=V1
V
* Parts per million (ppm): Indicates how many parts of solute (by mass or by volume) there are in a million (1,000,000 or 106) of parts of the solution (also in mass or volume).
1 ppm = __1 part of the solute__
106 solution parts
* Molality (W):lists the amount of matter in a solute (mols) by the mass in kilograms of the solvent:
W = no1
m2
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/quimica/o-que-e-concentracao-solucoes-quimicas.htm