[XenonX]

I sat for a quiz yesterday and i would like to have answer for a few questions...

1.Acid attacks limestone to form calcium salts.A piece of limestone weighing 46g reacts completely with 200cm3 of 2.0mol/dm ethanoic acid.What is the percentage purity of the piece of limestone?

PLs show working...

2.What will happen to two blouses each with one drop of oil stain immersed in two beaker filled with well water and distilled water respectively?Pls explain....

[AWK]

1 Read this link:
http://instructors.butlercc.edu/chemistry/carlson/Chem1labs/lab60.htm

2. nothing

[enahs]

Those are either some very small blouses or some really big beakers!

[XenonX]

well..i dun really understand..why there's nothing happen in the two beakers?

[AWK]

Water does not dissolve an oil

[XenonX]

not even a distilled water with soap?

[AWK]

2.What will happen to two blouses each with one drop of oil stain immersed in two beaker filled with well water and distilled water respectively?Pls explain....

I haven't seen soap here

[P]

You did not mention soap!         The hard water lathers less with soap than the soft water - therefore more soap is needed to clean the shirts in the harder water..     I believe this is because the ions in the harder water attract the ions on the surfactant the same way dirt would - thus you need more.

Have a nice weekend!   

[Yggdrasil]

The calcium in hard water forms insoluble salts with the fatty acyl ions in soap, forming a precipitate more commonly known as "soap scum."

[XenonX]

i am really sorry for missing out the "soap"...anyway...i get confused again as i don't know what is hard water?  And soft water???

[Yggdrasil]

http://en.wikipedia.org/wiki/Hard_water