Indirect Gravimetric Determination Partner Data Unknowe ID Code Mass of crucible
ID: 697822 • Letter: I
Question
Indirect Gravimetric Determination Partner Data Unknowe ID Code Mass of crucible Mass of crucible and mixture 1 25 3.3962 22.4 s22 Mass of mixture Mass of crucible after Ist heating 22 4505g Mass of crucible after 2nd heating Mass of crucible after 3rd hcating NA (If necded) In the items below, be sure to show calculations What mass of water was lost by the sample? Mass Cruci Lle and Mixfve 26silo Mass of Crmbe2 Mixtwe 8.02 What is the molar mass of water? How many moles of water were lost by the sample? , I 9 89 m6les SO2 How many moles of CuCl2·2H2O were present in the original sample?Explanation / Answer
The experimental details aren’t provided; however, I am guessing you want to find out the percent composition of a mixture of NaCl and CuCl2.2H2O based on gravimetry. Only CuCl2.2H2O will lose moisture on heating as
CuCl2.2H2O (s) ---------> CuCl2 (s) + 2 H2O (g)
As per the stoichiometric equation,
1 mole CuCl2.2H2O = 2 moles H2O.
Therefore, mole(s) of CuCl2.2H2O in the mixture = (0.01104 mole H2O)*(1 mole CuCl2.2H2O/2 mole H2O) = 0.00552 mole (ans).
Grams of CuCl2.2H2O in the original sample = (moles of CuCl2.2H2O in the sample)*(molar mass of CuCl2.2H2O) = (0.00552 mole)*(170.478 g/mol) = 0.9410 g (ans).
Percent composition of CuCl2.2H2O in the original sample = (mass of CuCl2.2H2O in the sample)/(mass of sample)*100 = (0.9410 g)/(3.3962 g)*100 = 27.7074% 27.71% (ans).
Grams of NaCl in the original sample = (3.3962 – 0.9410) g = 2.4552 g (ans).
Percent composition of NaCl in the original sample = (mass of NaCl in the sample)/(mass of sample)*100 = (2.4552 g)/(3.3962 g)*100 = 72.29256% 72.29% (ans).