Molecular Mass and Formula Mass class 9th chapter fundamental of chemistry

[@smart__by4308]

Taxonomic hierarchy sir please isko detail mai ek he video mai explain kare. Sir sirf ek lecture mere lye. Boht mushkil topic ha.

[@BioChemWala]

Ok g

[@ManzoorHussain-ix9ic]

When we arranged the classification units( taxa) in ladder form such type of arrangement of units or taxa is known as hierarchy of taxonomy

[@ManzoorHussain-ix9ic]

What is the difference between molecular mass and formula mass

[@BioChemWala]

Molecular mass is the mass of molecule ( covalent compound) while formula mass is the mass of formula unit ( ionic compound)

[@ManzoorHussain-ix9ic]

@@BioChemWala thanx sir for my reply. But water has a formula H2O and if we want to calculate its mass then it will be 18 a.m.u. Then it is a formula mass or molecular mass. Please don't be upset on my questionairs I want to learn from you sir. If you reply me sir I will be thankful to you.

[@BioChemWala]

You can asked about any doubts openly. Listen carefully, H2o has a mass of 18 if you put a unit of 18amu then it is a mass of one H2o molecule only and is called molecular mass and if we put a unit of gram e.g 18g then it is a mass of one mole of H2o molecules and is called molar mass. On the other hand when you calculate the mass of ionic compound e.g NaCl 58.5 amu then it is a mass of one NaCl molecule (also called formula unit) but if you put a unit of gram 58.5g then it is called formula mass or also called Gram formula mass. So simply molecular mass is used for the expression of mass of covalent compounds and formula mass is used for the expression of mass of ionic compound. H2o is a covalent compound so 18amu is a molecular mass not a formula mass. Understood?

[@SalaarKhan-x1r]

Both are almost same.