Page 250 - Chemistry eBook

Percent Composition of Hydrates
d = density HYDRATE: Compound that contains water within a crystalline structure
Density d = mV ANHYDRATE: Hydrate with water removed
Example of Hydrate: MgSO4  10H2O MoleInCtahilscuexlamtpiolen, sMgSO4 is dnisusmolbvedrinofwmateorl.es =
m = mass
V = volume
Table T
Important Formulas and Equations
To find the percent composition of water in a hydrate:
1. Find the mass of the entire water molecule = 10H O. (Mass of part)
Percent Error % error = 2 × 100 2. Find the mass of the entire hydrate. (Mass of awchceoplete)d value
3. Plug the values into the percent composition equation and solve.
parts per million = mass of solute × 1 000 000
given mass gram-formula mass
measured value – accepted value
Percent Composition
% composition by mass =
mass of part
× 100
mass of whole
Concentration
mass of solution
molarity = moles of solute liter of solution
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