![]() The steps in a general procedure of QSPR model construction using molecular descriptors are outlined below. They are studied to predict the activity, toxicity, and other properties resulting from the chemical structures of compounds. Quantitative structure–property relationship (QSPR) models frequently use molecular descriptors. Many types of molecular descriptors have been developed, such as the number of carbon atoms molecular weight predictive values of LogP (XLogP, ALogP, etc.) properties calculated from two-dimensional (2D) structures (e.g., Eccentric Connectivity Index ) and three-dimensional (3D) structures (e.g., charged partial surface area (CPSA) ) and properties based on quantum mechanics (orbital energies of highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), etc.). Owing to its good performance, convenience, number of descriptors, and a lax licensing constraint, Mordred is a promising choice of molecular descriptor calculation software that can be utilized for cheminformatics studies, such as those on quantitative structure–property relationships.Ī molecular descriptor is defined as the “final result of a logical and mathematical procedure, which transforms chemical information encoded within a symbolic representation of a molecule into a useful number or the result of some standardized experiment”. Performance benchmark results show that Mordred is at least twice as fast as the well-known PaDEL-Descriptor and it can calculate descriptors for large molecules, which cannot be accomplished by other software. Mordred can be easily installed and used in the command line interface, as a web application, or as a high-flexibility Python package on all major platforms (Windows, Linux, and macOS). To address these issues, we propose Mordred, a developed descriptor-calculation software application that can calculate more than 1800 two- and three-dimensional descriptors. ![]() However, users of those programs must contend with several issues, including software bugs, insufficient update frequencies, and software licensing constraints. Various molecular-descriptor-calculation software programs have been developed. Why does the calculator use 56.6% weight percentage instead of 28% for ammonium hydroxide?Ģ8% ammonia (NH 3) is equal to approximately 56.6% ammonium hydroxide.įor technical support or to provide feedback about this calculator, please email Technical Service.Molecular descriptors are widely employed to present molecular characteristics in cheminformatics. The normality of a solution is the molarity multiplied by the number of equivalents per mole. Thus, a 1 M solution of H 2SO 4 will be 2 N. This is because a single molecule of H 2SO 4 contains two acidic protons (H+ Ions). A 1 M solution of H 2SO 4 will contain one mole of H 2SO 4 in 1 liter of solution, but if the solution is titrated with a base, it will be shown to contain two moles of acid. Normality refers to compounds that have multiple chemical functionalities, such as sulfuric acid, H 2SO 4. Normality can only be calculated when we deal with reactions, because Normality is a function of equivalents. There is a relationship between normality and molarity. ![]() x 10 = 15.7 M How do I calculate the Normality of an acid or base from its Molarity? The above equation can then be used to calculate the Molarity of the 70 wt % Nitric Acid: Where: % = Weight % d = Density (or specific gravity) MW = Molecular Weight (or Formula Weight). The following equation is used for calculating Molarity where the concentration is given in wt %: The Molarity Calculator Equation (Molarity Conversion) Dividing the grams of HNO 3 by the molecular weight of HNO 3 (63.01 g/mole) gives the number of moles of HNO 3 / L or Molarity, which is 15.7 M. Knowing that the solution is 70 wt % would then allow the number of grams of HNO 3 to be calculated: (0.700)(1413g) = 989.1 grams HNO 3 per liter. Knowing the density of the acid to be 1.413 g/mL, we can calculate the weight of 1 L of 70% HNO 3 to be 1413 grams. % Nitric Acid the number of moles of HNO 3 present in 1 liter of acid needs to be calculated. Some chemists and analysts prefer to work in acid concentration units of Molarity (moles/liter). The concentration is expressed at 70% wt./wt. Using 70% concentrated Nitric Acid as an example: 70% Nitric Acid means that 100 grams of this acid contains 70 grams of HNO 3. How is the Molarity of a percentage solution calculated?
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