Science

Water of Hydration
Simon A. and Elissa R.
10/26

Purpose: to make a comparison between theoretical percentage vs. the experimental percentage of water in a hydrate

Procedure: as per labmanual page 1

Data:
|object |mass (g) |
|crucible 1st heating |22.517 |
|hydrate |5.005 ||crucible + hydrate 2nd |26.484 |
|crucible + hydrate 3rd |26.490 |

Weight of crucible + hydrate after first heating 27.522g
Data Analysis:1) 26.490g - 22.517g = 3.973g CaSO4
2) 40.01g Ca + 32.07g S + 63.96g O = 136.04g CaSO4
3) 3.973g CaSO4 / 136.04g CaSO4 = 0.0292 mol CaSO4
4) 27.522 – 26.490 = 1.032 g H2O
5) 2.02g H + 15.99g O =18.01g H2O
6) 1.032g H2O / 18.01g H2O = 0.0573 mol H2O
7) 3.973g CaSO4 / 136.04g CaSO4 = 0.0292 mol CaSO4 / .0292 = 1
1.032g H2O / 18.01g H2O = 0.0573 mol H2O / .0292 = 2
8) CaSO4 · 2 H2O
9)1.032g H2O / 5.005 CaSO4 · 2 H2O = 20.62%
10) 136.04 CaSO4 + 36.02 H2O = 172.06 CaSO4 · 2 H2O,
36.02 H2O/ 172.06 CaSO4 · 2 H2O = 20.93%

Error Analysis:
20.93% - 20.62% / 20.93% = 1.4% errorConclusion:
The purpose of this lab was to make a comparison between the theoretical percentage vs. the experimental percentage of water in a hydrate. We did this by taking a crucible and the lidand first heating it for 10 minutes or until it turned red to make sure that we got all the moisture out of it so it wouldn’t affect the weighing process later. After letting it cool in a desiccatorwe found the mass of the crucible. We then gathered as close as we could to 5 grams of the hydrate which for us was 5.005g and placed it inside the crucible and put it over the burner and placed thelid on it, carefully leaving a small gap for any gases to escape. After about 10 minutes of increasing the flame we took the crucible off and placed it in a desiccator and allowed it to cool. Then...