Lab Skills

Mass porcent

Solution = Solute + Solvent

mass % = mass solute/ mass of solution x 100%

volume % = volume of solute/ volume of solvent x 100%

Mole fraction

Xa = Nb/ Na+ Nb

Xa = Nc/ Na + Nb + Nc

Xa = Na/ Nt

Molarity

M= mol solute/ L of solvent

m(milliliters)= mol solute/ Kg of solvent

Density

D = m/v

D= g/mL or g/cm3

Dilution problems

(acid) M1 x V1 = M2 x V2 (base)

M = molarity of the concentration V= volume (must be in mL or L)

example

M1 x (24.5mL) = (0.25 M) x (35.8 ML) ->
M1= 0.362 M

24.7 mL of a HCI solution is completely neutralized by 35.8mL of a 0.25M NaOH solution. What is the concentration of the original HCI solution?

Titration

Quantitatiely determine concentration of unknown solution called titrand/analyte

titrand/analyte + titrand

what we need