Molarity, Molality, or Normality? (A Quick Review) | pdl-inc.info
Definitions of solution, solute, and solvent. How molarity is used to quantify the concentration of solute, and comcalculations related to molarity. Normality is similar in concept to molarity (refer to the previous article “Molarity”). Here is a simple example to show the relationships of Normal acid and base and this depends on the scope and application of a particular test method. The first three: molality, molarity and normality are dependant upon the Normality: There is a relationship between normality and molarity.
A mole of a substance equals the gram-formula mass or the gram-molar mass. This equals the sum of all of the masses of all the elements in the formula of the substance.
Basically, if one were to count all of the carbon atoms in one one mole of carbon, there would be 6. Using the information above, it is possible to calculate concentrations of solutions and make up solutions of desired concentration.Class 11 Chap 01 : Some Basic Concept Of Chemistry 03 : MOLARITY and MOLALITY -- MOLARITY-- MOLALITY
It is also possible to use this information to determine how much of a given base would be needed in order to neutralize a specific acid and reach a pH of 7. There are five units of concentration that are particularly useful to chemists. Percentages can also be determined for solids within solids.
Molarity, Molality, or Normality? (A Quick Review)
The molal unit is not used nearly as frequently as the molar unit. A molality is the number of moles of solute dissolved in one kilogram of solvent. Be careful not to confuse molality and molarity.
Molality is represented by a small "m," whereas molarity is represented by an upper case "M. One liter of water has a specific gravity of 1. Most other solvents have a specific gravity greater than or less than one.
Derive relation between molarity and normality | Homework Help | myCBSEguide
Therefore, one liter of anything other than water is not likely to occupy a liter of space. To make a one molal aqueous water solution of sodium chloride NaClmeasure out one kilogram of water and add one mole of the solute, NaCl to it. The atomic weight of sodium is 23 and the atomic weight of chlorine is Therefore the formula weight for NaCl is 58, and 58 grams of NaCl dissolved in 1kg water would result in a 1 molal solution of NaCl.
The molar unit is probably the most commonly used chemical unit of measurement. Molarity is the number of moles of a solute dissolved in a liter of solution. A molar solution of sodium chloride is made by placing 1 mole of a solute into a 1-liter volumetric flask.
Taking data from the example above we will use 58 grams of sodium chloride. Water is then added to the volumetric flask up to the one liter line. The result is a one molar solution of sodium chloride. There is a relationship between normality and molarity. Normality can only be calculated when we deal with reactions, because normality is a function of equivalents. The formula to calculate this is: For example, how many grams of sodium hydroxide would you need to dilute to a liter to make a 1N NaOH solution?
The equivalent mass is 40 as determined above. Similarly, to make 0. The number of hydrogen ions it can produce is 1 The acid hydrogens are usually on the left side of a chemical formula. Both of the chemicals in the examples above, sodium hydroxide and potassium hydrogen phthalate, are considered dry chemicals, which makes it relatively straightforward to calculate their Normalities. For liquid chemicals where the main compound is only a fraction of the total volume, such as the concentrated forms of hydrochloric HClsulfuric H2SO4and phosphoric H3PO4 acids, a few additional calculations must be performed to make a solution of a particular Normality.
The next article will describe and give examples of these additional calculations. These are not only useful for making acid and base solutions, but are useful in calculating concentrations of any type of concentrated dissolved compounds such as alum aluminum sulfatebleach sodium hypochloriteferric chloride, and the many other solutions used in wastewater treatment.
Please note that this article specifically covers what is typically found in a wastewater treatment laboratory.