Post Lab Chemistry
Post Lab Questions
1) How would your calculation of the average number of water molecules present in Epsom salt be affected
if you heated your sample too strongly and and too long and decomposition started to take place? (Too
High, Too Low, Unchanged) Explain
2) How would the calculated number of water molecules present in Epsom salt be affected if procedure was
changed so the analysis was preformed using 8.500g of hydrated salt instead of 1.500g? (Too High, Too
Low, Unchanged) Explain
3) Calculate the mass percent of water contained in a sample of MgSO4.7H2O?
4) A sample of raw mining ore contains a hydrated salt called copper sulfate pentahydrate, CuSO4.5H2O. If
a 10.000g of the ore loses 0.499g of water when heated strongly, what is the mass percentage of
CuSO4.5H2O in the raw ore sample?
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Experiment 3 Report Sheet
Hydration of Epsom Salt
Data Collection
Item
Trial 1
Trial 2
Trial 3
Trial 4
1. Mass of Crucible
2. Mass of Crucible and Salt before heating
[3] Initial Mass of Epsom Salt
4. Mass of Crucible and Salt after heating
[5] Mass lost during heating (water) (g)
[6] Mass of Residue Remaining (MgSO4) (g)
[7] Moles of water lost (mol)
[8] Moles of Magnesium Sulfate remaining (mol)
[9] Ratio of moles of H2O to MgSO4
[10] Ratio of moles of H2O to MgSO4 rounded to the nearest integer
[11] Average of mole ratio H2O for all 4 of your trials [9] then rounded to integer
In the following tables, items with [bracketed] numbers (i.e. [1]) are to be computed from your experimental data. The others are collected as part of your experiment. Remember to record the values on the balance to three decimal places.
Post Lab Questions
1) How would your calculation of the average number of water molecules present in Epsom salt be affected if you heated your sample too strongly and and too long and decomposition started to take place? (Too High, Too Low, Unchanged) Explain
2) How would the calculated number of water molecules present in Epsom salt be affected if procedure was changed so the analysis was preformed using 8.500g of hydrated salt instead of 1.500g? (Too High, Too Low, Unchanged) Explain
3) Calculate the mass percent of water contained in a sample of MgSO4.7H2O?
4) A sample of raw mining ore contains a hydrated salt called copper sulfate pentahydrate, CuSO4.5H2O. If a 10.000g of the ore loses 0.499g of water when heated strongly, what is the mass percentage of CuSO4.5H2O in the raw ore sample?
8.0.1291.1.339988.308172
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