Question

CHM 010 On-Line Lab, Formula of a Hydrate PURPOSE: To determine the formula of Cuso..x H20. In other words, to determine the value of "X". PROCEDURE: When copper(II) sulfate x hydrate, a blue crystalline solid containing embedded water molecules (called a hydrate), is heated in air, it loses the water molecules and the blue solid is transformed to a white anhydrous (no water) crystal known as anhydrous copper(II) sulfate. The "x" represents a whole number of water molecules attached to one molecule of CuSO4. In this experiment we want to determine the value of "x". Use the computer simulation to determine the formula of Cuso.. xH0. In other words, what is the value of x? Is the formula CuSO 1H,0 or is it CusO.. 2 H20, or is it Cuso. 3 H,0, or is it Cuso. 4 H20, or is it Cuso.. 5 H,O, etc. In this experiment we will find out. The computer simulation can be found by clicking on the URL below: http://introchem.chem.okstate.edu/DCICLA/Empirical.html For the simulation to work, you need to use either internet explorer, or allow google chrome to use adobe flash player when you click on this URL. From the simulation: • Record the initial mass of the Cuso. . x H20. • When you are ready, click to start heating. . Once the hydrate sample turns white, you have reached the final mass. • Record the final mass in the data table. • Now do the necessary calculations to determine the formula of the hydrate. When you complete the data page below, e-mail it to me.

Answer 1

Formula of hydrate :

a. Initial mass of hydrated CuSO4 . xH2O = 0.1797 g

b. Final mass of anhydrous CuSO4                 =   0.1149 g

c. Mass of anhydrous CuSO4                         =   0.1149g

d. Mass of H2O                                               = 0.1797 – 0.1149 = 0.0648 g

e.   Molar mass of CuSO4 = 160 g / mol

f. Molar mass of H2O = 18 g / mol

g. Moles of CuSO4                     =       0.1149/160    =   7.18125 x 10-4 moles

h. Moles of H2O                       =          0.0648/ 18         = 3.6 X 10-3 moles

i. Value of x                             =         moles of H2O / moles of CuSO4                                                   

=          3.6 X 10-3 / 7.18125 x 10-4 =          5.013

Rounding off to nearest integer value of x = 5            

Hence the hydrated copper sulfate is CuSO4 . 5H2O