quantitive chemistry

• what is "the mole" ?

  the name given to the amount of a substance

  the amount of a certain substance that contains an avogadro number of particles (6.02 x 10 ^ 23) particles
• what is the formula for number of moles ?

  Number of moles = Mass in g of an element or compound/ relative formula mass of the element or compound (mr)
• calculate the number of moles in 90g of water (H20).

  Ar (O) = 16 Ar (H) = 1

  90 / (16+(1X2)) = 5 moles
• what is the equation for concentration using moles ?

  concentration (mol/dm^3) = number of moles in solute (mol)/ volume of solvent(dm^3)