To ensure that all of the solid dissolved in Step 10 of the Procedure, a student

Question

To ensure that all of the solid dissolved in Step 10 of the Procedure, a student added 10mL (instead of 1-2mL) of hot distilled water to the mixture, and then followed the Procedure as written. a) Would her percent yield of alum likely have been increased or decreased as a result of this procedural change? Briefly explain b) If your answer to (a) is 'increased' would she have obtained an even greater percent yield by adding 20mL of hot distilled water? Briefly explain. If your answer to (a) is 'decreased' briefly explain what she could have done after dissolving the solid to improve her percent yield.

Step 10: Heat the contents of the synthesis beaker [KAl(OH)4 and H2SO4] on a hot plate, with constant stirring, until all of the solid dissolves. If necessary, add 1-2 mL of distilled water to the hot solution to facilitate complete dissolution.

Explanation / Answer

Adding too much hot water would reduce the final yield of alum from the given experiment. The crystals formed would remain in solution state. The solution is very dilute.

To fix this, the student must concentrate and reduce the final volume of solution to get the crystals of alum out of solution.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.