Helmenstine holds a Ph. She has taught science courses at the high school, college, and graduate levels. Facebook Facebook Twitter Twitter. Updated September 25, Key Takeaways Normality is a unit of concentration of a chemical solution expressed as gram equivalent weight of solute per liter of solution.
A defined equivalence factor must be used to express concentration. Normality is the only unit of chemical concentration that depends on the chemical reaction being studied. Normality is not the most common unit of concentration, nor is its use appropriate for all chemical solutions. Typical situations when you might use normality include acid-base chemistry, redox reactions, or precipitation reactions. For most other situations, molarity or molality are better options for units.
Featured Video. Cite this Article Format. Helmenstine, Anne Marie, Ph. How to Calculate Normality Chemistry. Calculating Concentrations with Units and Dilutions. Calculating the Concentration of a Chemical Solution. List of the Strong Acids and Key Facts.
Freezing Point Depression Example Problem. What is the Difference Between Molarity and Molality? How to Make a Phosphate Buffer Solution.
Normal Concentration Definition in Chemistry. 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 HCl , sulfuric H2SO4 , and 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 sulfate , bleach sodium hypochlorite , ferric 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.
There are exceptions to how the concentrations of acids and bases are measured, and this depends on the scope and application of a particular test method. All past articles are posted on our website. Go to www. Acidity and Alkalinity. Ammonia Nitrogen. Making Normal Solutions. BOD Test Requirements. Phosphorus 1. If you want any of our calculators as widgets on your website, or if you observed that we missed any calculator on our website, please let us know at calculatorhut gmail.
We would love to hear from you! Happy calculating! What is normality? What is the gram equivalent of a substance? How is normality calculated? What is the significance of normality? Normality plays an important role in chemical laboratories, in preparation of various solutions, drugs, and medicines, water treatment plants, etc. In reduction-oxidation or redox reactions, the number of electrons that are involved for exchange either by a reducing agent or an oxidizing agent is considered as normality.
In precipitation reactions, the number of ions comprises the normality of the solution.
0コメント