ahmed.m
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Last week my class partook in a chemistry practical as part of our coursework. The practical was to make a salt (magnesium sulfate crystals). I am rather apprehensive over a few of the following questions, and so I am addressing all chemists on TSR for help.

1. "Suggest a reason why the procedure in step 2 and 3 is only possible with a carbonate that is insoluble in water such as magnesium carbonate."
>Step 2 was adding magnesium carbonate to sulfuric acid and stirring until the solution went clear, and repeating this step until the solution would no longer clear.
>Step 3 was to heat the beaker containing the solution until it became clear again, and then to add more magnesium carbonate so that some solid was in excess.
Was this something pertaining neutralisation reactions or?

2. "Suggest how your sample of magnesium sulfate would be different if in step 6, all of the water had been evaporated off."
>Step 6 being to boil the solution of magnesium sulfate on a tripod gauze until about 2/3 water evaporates.
Presumably wanting you to discuss the state of the crystals after total evaporation(?)

3. "Suggest one reason why a student carrying out the preparation apparently obtains a yield over 100%."

(this isnt my post if anyone was wondering but i have the exact same questions i need to answer. originally posted by llennon_04)
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TheonlyMrsHolmes
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(Original post by ahmed.m)

3. "Suggest one reason why a student carrying out the preparation apparently obtains a yield over 100%."
How it possible to obtain a yield over 100%? Please also let me know if you find the answer.
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charco
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(Original post by TheonlyMrsHolmes)
How it possible to obtain a yield over 100%? Please also let me know if you find the answer.
Impurity, maybe the weighed product is wet.
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