home > q&a board > chemistry > topic: pre laboratory question

Q BgQuestion:

Scholar
Karma Points: 213
Respect (97%):
posted by  Element on 3/24/2008 6:42:39 PM  |  status: Closed  

Pre laboratory question

Course Textbook Chapter Problem
General Chemistry N/A N/A N/A
Question Details:
Describe clearly and concisely how you would accomplish each of the following on a semi-micro scale.
 
A. Adjust the pH of a 2M Hcl solution to pH 2.
 
B. Decant a supernatant liquid.
 
C. Wash a precipitate.
 
Bonus Point Alert! Earn +4 additional karma points for helping this annual member.

AAnswers:

Answer Question
Apprentice
Karma Points: 109
posted by koh on 3/24/2008 7:04:19 PM  |  status: Live
Asker's Rating: Lifesaver   
Element's comment:
"Thanks!"
Response Details:
a) Adjust the pH of a 2M HCl solution to pH2
--add more HCl to make the solution more concentrated, if it gets past pH 2, add a bit of base - dropwise until it becomes pH 2.

b) Decant a supernant:

with a stirring rod, pour the clear supernatant liquid down it held against the inside wall of the container.

c) wash a precipitate:
add distilled water (DI) to the solid, water is used b/c it does not interfere w/ the analysis. stir thoroughly which disperses the solid and removes the remaining foreign ions on the solid.

hope that helped! the flowchart for this lab is ridiculously long...
Answer Question
Ask New Question

Join Cramster's Community

Cramster.com brings together students, educators and subject enthusiasts in an online study community. With around-the-clock expert help and a community of over 100,000 knowledgeable members, you can find the help you need, whenever you need it. Join for free today » How Cramster is different from tutoring »

Need Help In

Useful Links