easechemistry

Conversion Factors|Definition| "Conversion factor is a ratio - this ratio is always equal to 1 - used to covert one unit into other unit. Units are inter-converted simply by multiplying or dividing the suitable conversion factor". For conversion, we should have appropriate prior information.For instance,  if we want to inter-convert " inches " & " feet " we should have prior information  like,  1 foot = 12 inches  If we want to inter-convert " hours"&  " minutes"  then we should know, 1 hour= 60 minutes Few useful Conversion Factors Examples Dr. Ali measured mass of a sample , as 0.98lb later on his lab attendant needs to be take this mass in kilograms. What attendant will do to convert pounds into kilograms? Attendant knows   1 kilogram = 2.2 lb Form above prior information , attendant gets two conversion Factors.we can see those two conversion factors from above table, 1kg/ 2.2 lb   and     2.2lb/1kg Select...

Mole is one of the seven basic physical quantities.  It is used to measure quantity of a chemical substance in term of numbers of elementary particles -  elementary particles  of a chemical substance can be atoms , molecules,   ions, formula units  etc - just like one dozen of any thing has  12 items of that thing.  1 mole of any substance= 6.022x10^23 elementary particles/mol. Like  1 dozen of any thing= 12 items/dozen. DEFINITION  A mole of any substance has exactly 6.022140766x10^23 elementary particles of given substance.This number is usually written in round off as 6.022x10^23.This number is known as Avogadro's  number. Symbol used for Avogadro's number is NA . SYMBOL & UNIT Symbol designated for mole is "n" and its unit is "mol". EXAMPLES 1 mole of sodium(Na) = 6.022x 10^23 atoms/mol. 1 mole of water(H2O) = 6.022x 10^23 molecules/mol. 1 mole of sodium ions(Na+) = 6.022x10^23 ions/mol. 1 mole of sodium chloride(NaCl) = 6.022x1...