Question

Post lab Questions: 1. While performing the formula of hydrate laboratory experiment, the lid accidently slips over the crucible to completely seal the crucible. a. What effect this change will cause on your calculated experimental results? Explain. b. Would your calculated percent water of hydration be high, low or unaffected? Explain your answer. 2. A student was asked to identify a sample of unknown hydrate. Student was provided with the following experimental data. 3.51 g sample of the hydrate when heated loses water completely and the mass of the residue was found to be 2.22 g. Student was provided with two reference compounds from which student needs to identify the unknown: Cu(NO3)2. 3H20 and Cu(NO3)2.6H20. Answer the followings. a. Calculate percent water of hydration in the sample. (show your calculations) b. Identify the formula of the hydrate.

Answer 1

- X100%. Answers - Page No - o Given, Formula of Hydride laboratory experiment Setu minction ; The lid accidently slips over the coucible to completely seal the crucible. (a) Now, - we know that the % of hydrogen for water is given as, 1 mass of the watu .. % Hylation - .. mass of the sample Now, this mais of watu (Mg) is equal to the mais of water getting evaporated through salt by Heating - Mass of the sample prior to - heating - mass of the sample after - Heating Now, the lid has sealed the coucible completely when it falls Accidently there will be no complete loss of the watu molecules. Therefore Number of water Molecules in Hydrogen Hydration will be less.

Page No - (b) from the above % Hydration touation can infer that % watu of Hydration will be less since the value will be less than the Actual value lie, sample value) (2) (a) Inition maus of the sample (m;)= 3-519 Mas of sample ofte heating (mp) = 2.229 Mass of water in the sample (mww) = (initial mais of the sample) - mass of sample aftu heating = (3.518)-(2.229) - 1.29 g % watu of hydration in the sample - mass of water in the sample (mw) un - XOO initial mass of the sample (m:) = 1.29 xlop 1 X to = 36.75 7. (6) Molar Mans of CuCNO3)2 = 187 g Mass of Cu(NO3), in the sample = Mass of sample aftu heating (mp) = 2.229 Maus of H₂O in Number of moles of tho in the sample : - the sample Holar mass of H₂O

- Page No - 1.29 18 - 0.0117 moles Ratio between number of moles of H₂O and number of Moles of Cu(NO3), in the sample o of moles of H₂0 O no of moles of CulNG), < 0.0717 0.0119 = 6:025 - This Patio is closer to the ratio blo no of moles H₂O and no of moles. Of Cuckol Of Cu(NG), 6420 - which is 6 is the compound Must be Cuckly ),- 64, .