Tag Archives: number

What is gold number ?

It is the amount of lyophilic sol required in milligrams to prevent the the coagulation of 10ml gold sol by the addition of 1 ml, 10% NaCl solution .

Why is carbon important for forming complicated molecules? Or why carbon makes a large number of molecules ?

The answer to this question is very simple . There are two major reasons behind it. 1. Catenation :- It is the property by which the carbon can make long chains, branched chains and ring or cylic structural by joining with its own atoms. Due to this it can make a variety of molecules. 2.Continue reading “Why is carbon important for forming complicated molecules? Or why carbon makes a large number of molecules ?”

What is Wurtz reaction?

It is the reaction between alkyl halides and sodium in the dry ether to give alkanes with higher number of carbon. 2R-X + 2 Na —> R-R +2NaX

Some important terms

1. Co-ordination number Number of spheres touching one Sphere in a close packed structure is called co-ordination number of a lattice 2. Unit cell The smallest repeating pattern in a crystal lattice is called a unit cell. Characteristics of unit cell Are unit cell has a characteristic dimensions along the three edges a,b,c and interfacialContinue reading “Some important terms”

How many atoms are there in 1 gram of carbon?

For  calculation of number of atoms we have to calculate the number of moles present in 1gram carbon. Multiply the number of moles with Avogadro number. Step I  Number of moles in 1 gram of carbon = given mass / molar mass Molar mass (molecular or atomic mass expressed in grams) = 12g So theContinue reading “How many atoms are there in 1 gram of carbon?”

How many oxygen atoms are there in 90g of H2O molecule?

1 molecule of H2O has 1 atom of oxygen. Firstly we will calculate the number of atoms in 90g of H2O. we will explain it in two steps:- Step I:- No.of moles of H2O = given mass / molar mass No. of moles = 90/18 = 5 moles No. Of molecules = No. of molesContinue reading “How many oxygen atoms are there in 90g of H2O molecule?”

What is the number of moles of O-atom in 126 AMU of HNO3?

Here we have 126 AMU of HNO3, Molar mass of HNO3 is 1+14+16×3 = 63amu Number of molecules of HNO3 are = 126/63 = 2 Here we have 2 molecules Each molecule have 3 atoms of oxygen. So no. of oxygen atoms= 3×2 =6 atoms No. Of moles = given particles/ avogadro number No. ofContinue reading “What is the number of moles of O-atom in 126 AMU of HNO3?”