## Chemistry formulas for Atoms, Molecules and Chemical Arithmetic Part II

### Gram Atomic Weight (GAW) related Chemical Formulas

·         No. of Gram Atoms or Mole Atoms = Weight of an Element/GAW
·         Weight of an Element in gram = No. of Gram Atoms x GAW
·         No. of atoms in 1 GAW = 6.02x1023
·         No. of atoms in given substance = 6.02x1023 x Weight/GAW
·         No. of atoms in 1 gram of an element = 6.02x1023/Atomic Weight

### Gram Molecular Weight (GMW) related Chemical Formulas

·         No. of Gram molecules or Mole Molecules = Weight of Substance/GMW
·         Weight of Substance in gram = No. of Gram Molecules x GMW
·         Avogadro’s No. = 6.02x1023 per mol

### Mole Concept related Chemical Formulas

·         1 mole contains 6.02x1023 particles
·         1 mole of an atom = 1 GAW of it
·         1 mole of a compound = 1 GMW of it
·         Examples, 1 mole of Na = 23 g
·         1 mole of H2O = 18 g
·         1 mole of OH- ions = 17 g
·         1 mole = 1 gram molecules
·         1 mole = 1 gram molecular weight
·         1 mole = 22.4 litres at NTP
·         1 mole = 6.02x1023 molecules
·         1 mole = 1 gram atomic weight
·         1 mole = 6.02x1023 atoms
·         No. of Moles = Weight of Substance in Gram/Gram Molecular Weight
·         No. of Moles = No. of Unitary Particles/Avogadro’s No.
·         No. of Moles = Volume in Litres at NTP/22.4 Litres

### Gram Molecular Volume related Chemical Formulas

·         1 Gram Molar Volume = 22.4 Litres
·         Example, Volume of 16 gram (1 mole) of CH4 at STP= 22.4 Litres
·         Volume of 2 gram (1 mole) of H2 at STP = 22.4 Litres
·         Weight of 11.2 litres of any Gas at STP = VD (Vapour Density) of that Gas in Gram
·         Density of Gas at NTP = Molar Weight in Gram/22400 mL