In: Chemistry
What is the percent water by weight of lithium perchlorate trihydrate?
Solution
Lithium perchlorate trihydrate = LiClO4*3H2O
% water = ?
Lets first calculate the molar mass of the LiClO4*3H2O
Molar mass is the sum of atomic masses of the elements in the formula
Molar mass of LiClO4*3H2O = Li + Cl+ (O*7)+(6*H)
= 6.941 + 35.453 +(15.999 *7)+(6*1.0079)
= 160.4344 g per mol
Now lets calculate the percent of water
Mass of 3 mol H2= = 3* 18.0148 g = 54.0444 g
% H2O = (mass of H2O / total mass) * 100 %
% H2O = (54.0444 g / 160.4344 g) *100%
% H2O = 33.69 %